kandi background

eureka | AWS Service registry for resilient mid | Configuration Management library

by Netflix Java Version: v2.0.0 License: Apache-2.0

by Netflix Java Version: v2.0.0 License: Apache-2.0

kandi X-RAY | eureka Summary

eureka is a Java library typically used in Telecommunications, Media, Media, Entertainment, Devops, Configuration Management, Docker applications. eureka has no bugs, it has no vulnerabilities, it has build file available, it has a Permissive License and it has medium support. You can download it from GitHub, Maven.

Eureka is a REST (Representational State Transfer) based service that is primarily used in the AWS cloud for locating services for the purpose of load balancing and failover of middle-tier servers. At Netflix, Eureka is used for the following purposes apart from playing a critical part in mid-tier load balancing.

Support

Support

Quality

Quality

Security

Security

License

License

Reuse

Reuse

kandi-support Support

eureka has a medium active ecosystem.
It has 11661 star(s) with 3655 fork(s). There are 969 watchers for this library.
There were 4 major release(s) in the last 6 months.
There are 51 open issues and 559 have been closed. On average issues are closed in 79 days. There are 11 open pull requests and 0 closed requests.
It has a neutral sentiment in the developer community.
The latest version of eureka is v2.0.0

eureka Support

Best in #Configuration Management

Average in #Configuration Management

eureka Support

Best in #Configuration Management

Average in #Configuration Management

quality kandi Quality

eureka has 0 bugs and 0 code smells.

eureka Quality

Best in #Configuration Management

Average in #Configuration Management

eureka Quality

Best in #Configuration Management

Average in #Configuration Management

security Security

eureka has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.
eureka code analysis shows 0 unresolved vulnerabilities.
There are 0 security hotspots that need review.

eureka Security

Best in #Configuration Management

Average in #Configuration Management

eureka Security

Best in #Configuration Management

Average in #Configuration Management

license License

eureka is licensed under the Apache-2.0 License. This license is Permissive.
Permissive licenses have the least restrictions, and you can use them in most projects.

eureka License

Best in #Configuration Management

Average in #Configuration Management

eureka License

Best in #Configuration Management

Average in #Configuration Management

build Reuse

eureka releases are available to install and integrate.
Deployable package is available in Maven.
Build file is available. You can build the component from source.
Installation instructions are not available. Examples and code snippets are available.
eureka saves you 18519 person hours of effort in developing the same functionality from scratch.
It has 36652 lines of code, 3307 functions and 419 files.
It has medium code complexity. Code complexity directly impacts maintainability of the code.

eureka Reuse

Best in #Configuration Management

Average in #Configuration Management

eureka Reuse

Best in #Configuration Management

Average in #Configuration Management

Top functions reviewed by kandi - BETA

kandi has reviewed eureka and discovered the below as its top functions. This is intended to give you an instant insight into eureka implemented functionality, and help decide if they suit your requirements.

Generates a list of service urls from a DNS client configuration .

Checks if two instances are equal .

Initialize the eureka client context .

Binds the EIP to the EIP .

Get application durations from multiple regions .

Creates a composite resolver that can be used to resolver on the same instance .

Creates or returns the jersey client .

Generate Payload .

Gets all the Eureka containers .

Sends a request to the eureka client using the eureka client .

Get all kandi verified functions for this library.

Get all kandi verified functions for this library.

eureka Key Features

For aiding Netflix Asgard - an open source service which makes cloud deployments easier, in + Fast rollback of versions in case of problems avoiding the re-launch of 100’s of instances which could take a long time. + In rolling pushes, for avoiding propagation of a new version to all instances in case of problems.

For our cassandra deployments to take instances out of traffic for maintenance.

For our memcached caching services to identify the list of nodes in the ring.

For carrying other additional application specific metadata about services for various other reasons.

eureka Examples and Code Snippets

See all related Code Snippets

Community Discussions

Trending Discussions on eureka

Building Docker image from spring maven project for arm64 platform
Spring Cloud Gateway; Spring MVC found on classpath, which is incompatible with Spring Cloud Gateway Issue
Use main Gradle project to define all dependencies versions
parsing error in yml file for microservices
Configure Spring Gateway with Spring Authorization Server
AWS API Gateway and Spring boot custom authorization
Spring RestTemplate and getForObject for Microservices issues
How to install nc in mysql container
How to make a proper reactive extension on Eureka SelectableSection
Issue selecting multiple inputs using selectInput

Trending Discussions on eureka

QUESTION

Building Docker image from spring maven project for arm64 platform

Asked 2022-Mar-24 at 00:10

I'm in a Spring course, and I have a maven application (downloaded from the course resources) built from spring initializr. I can build a local Docker image with mvn spring-boot:build-image (no Dockerfile in the project). By default a Docker image is built as linux/amd64, but I am working with a M1 Apple Silicon chip (arm64). I've been looking many workarounds but with no success. Lastly, I found that maybe adding a Dockerfile and specifying the platform it would build the image accordingly.

My goal is to build a docker image for arm64 architecture.

So, I created a Dockerfile:

FROM --platform=linux/arm64 maven:3.8.4-jdk-11 AS build
COPY src /home/path_to_app/src
COPY pom.xml /home/path_to_app
RUN mvn -f /home/path_to_app/pom.xml spring-boot:build-image -DskipTests

My project structure is:

standard maven structure

In terminal, at same pom.xml directory I run: docker buildx build --platform linux/arm64 --tag <mytag> .

Logs successful until =>Building image 'docker.io/myusername/myimage:mytag', then an exception occurs and build fails.

#8 125.7 [INFO] 
#8 125.7 [INFO] <<< spring-boot-maven-plugin:2.5.0:build-image (default-cli) < package @ currency-exchange-service <<<
#8 125.7 [INFO] 
#8 125.7 [INFO] 
#8 125.7 [INFO] --- spring-boot-maven-plugin:2.5.0:build-image (default-cli) @ currency-exchange-service ---
#8 125.8 [INFO] Building image 'docker.io/myname/myimage:0.0.1-SNAPSHOT'
#8 125.8 [INFO]
#8 125.8 [INFO] I/O exception (java.io.IOException) caught when processing request to {}->docker://localhost:2376: com.sun.jna.LastErrorException: [2] No such file or directory
#8 125.8 [INFO] Retrying request to {}->docker://localhost:2376
#8 125.8 [INFO] I/O exception (java.io.IOException) caught when processing request to {}->docker://localhost:2376: com.sun.jna.LastErrorException: [2] No such file or directory
#8 125.8 [INFO] Retrying request to {}->docker://localhost:2376
#8 125.8 [INFO] I/O exception (java.io.IOException) caught when processing request to {}->docker://localhost:2376: com.sun.jna.LastErrorException: [2] No such file or directory
#8 125.8 [INFO] Retrying request to {}->docker://localhost:2376
#8 125.9 [INFO] ------------------------------------------------------------------------
#8 125.9 [INFO] BUILD FAILURE
#8 125.9 [INFO] ------------------------------------------------------------------------
#8 125.9 [INFO] Total time:  02:04 min
#8 125.9 [INFO] Finished at: 2022-03-22T21:08:20Z
#8 125.9 [INFO] ------------------------------------------------------------------------
#8 125.9 [ERROR] Failed to execute goal org.springframework.boot:spring-boot-maven-plugin:2.5.0:build-image 
(default-cli) on project currency-exchange-service: Execution default-cli 
of goal org.springframework.boot:spring-boot-maven-plugin:2.5.0:build-image 
failed: Connection to the Docker daemon at 'localhost' failed with error "[2] 
No such file or directory"; ensure the Docker daemon is running and accessible:
com.sun.jna.LastErrorException: [2] No such file or directory -> [Help 1]

My pom.xml:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.5.0</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.somename.microservices</groupId>
    <artifactId>mymicroservice-service</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>mymicroservice-service-docker</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>11</java.version>
        <spring-cloud.version>2020.0.2</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-sleuth</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-sleuth-zipkin</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.amqp</groupId>
            <artifactId>spring-rabbit</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>
        <dependency>
            <groupId>io.github.resilience4j</groupId>
            <artifactId>resilience4j-spring-boot2</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <image>
                        <name>myusername/myprefix${project.artifactId}:${project.version}</name>
                    </image>
                    <pullPolicy>IF_NOT_PRESENT</pullPolicy>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
        </repository>
    </repositories>

</project>

My docker daemon is running. Can't figure out why it tries to reach localhost:2376 (There is no such port in my project). My DOCKER_HOST is set to unix:///var/run/docker.sock and works fine. Tried to add to daemon.json:

{
"hosts": ["tcp://127.0.0.1:2376", "unix:///var/run/docker.sock"]
}

but docker daemon can't initialize (binding error, port already in use)

I don't know where does com.sun.jna.LastErrorException come from.

I suspect that maybe Docker in docker (dind) is needed, but I don't know how to set it up in my Dockerfile. Or maybe a port binding configuration.

Thank in advance for any help!!!

Note: I just want to build the image locally. I don't wish pushing to docker registry. I don't want any other stages in the build process.

ANSWER

Answered 2022-Mar-24 at 00:10

Building an ARM-based image is not currently possible with mvn spring-boot:build-image, because the Cloud Native Buildpacks builders that Spring Boot integrates with do not support this. This is one of the possible items of focus on the Paketo buildpacks 2022 roadmap, which you can cast votes for.

CNB documents a work-around for this, but it's not simple to set up and run.

RUN mvn -f /home/path_to_app/pom.xml spring-boot:build-image -DskipTests

You would need Docker-in-Docker to make something like this work, since the CNB builder processes that would run inside the Docker container need to talk to the Docker daemon. Regardless, this would not allow you to build an ARM image for the reasons stated above.

Source https://stackoverflow.com/questions/71581008

QUESTION

Spring Cloud Gateway; Spring MVC found on classpath, which is incompatible with Spring Cloud Gateway Issue

Asked 2022-Mar-16 at 07:16

I got this below error when run the API-GATEWAY, I tried so many ways but I couldn't solve this issue.

Description:

Spring MVC found on classpath, which is incompatible with Spring Cloud Gateway.

Action:

Please set spring.main.web-application-type=reactive or remove spring-boot-starter-web dependency.

Main Class

package com.sample.apigateway;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;

@SpringBootApplication
@EnableEurekaClient
public class ApiGatewayApplication {

    public static void main(String[] args) {
        SpringApplication.run(ApiGatewayApplication.class, args);
    }

}

application.yml

spring:
  application:
    name: GATEWAY-SERVICE

  cloud:
    gateway:
      routes:
        - id: USER-SERVICE
          uri: lb://USER-SERVICE
          predicates:
            - Path=/users/**
        - id: DEPARTMENT-SERVICE
          uri: lb://DEPARTMENT-SERVICE
          predicates:
            - Path=/departments/**

eureka:
  client:
    register-with-eureka: true
    fetch-registry: true
    service-url:
      defaultZone: http://localhost:8761/eureka/

  instance:
    hostname: localhost

server:
  port: 9191

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.5.3</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.sample.apigateway</groupId>
    <artifactId>apigateway</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>apigateway</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>11</java.version>
        <spring-cloud.version>2020.0.3</spring-cloud.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-webflux</artifactId>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-boot-starter</artifactId>
            <version>3.0.0</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

Full Error Message

2021-07-30 23:12:02.420  WARN 19032 --- [           main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.cloud.gateway.config.GatewayClassPathWarningAutoConfiguration$SpringMvcFoundOnClasspathConfiguration': Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.cloud.gateway.config.GatewayClassPathWarningAutoConfiguration$SpringMvcFoundOnClasspathConfiguration]: Constructor threw exception; nested exception is org.springframework.cloud.gateway.support.MvcFoundOnClasspathException
2021-07-30 23:12:02.423  INFO 19032 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2021-07-30 23:12:02.441  INFO 19032 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2021-07-30 23:12:02.454 ERROR 19032 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************
APPLICATION FAILED TO START
***************************

Description:

Spring MVC found on classpath, which is incompatible with Spring Cloud Gateway.

Action:

Please set spring.main.web-application-type=reactive or remove spring-boot-starter-web dependency.


Process finished with exit code 1

ANSWER

Answered 2021-Aug-01 at 06:17

Please note that Spring Cloud Gateway is not compatible with Spring MVC (spring-boot-starter-web). This is outlined in section "How to include Spring Cloud Gateway in the official reference documentation":

Spring Cloud Gateway is built on Spring Boot 2.x, Spring WebFlux, and Project Reactor. As a consequence, many of the familiar synchronous libraries (Spring Data and Spring Security, for example) and patterns you know may not apply when you use Spring Cloud Gateway.

Additionally, it is stated that:

Spring Cloud Gateway requires the Netty runtime provided by Spring Boot and Spring Webflux. It does not work in a traditional Servlet Container or when built as a WAR.

As already suggested by the error message, you would need to remove the dependency on spring-boot-starter-web. You can list all your direct and transitive dependencies with the following command:

mvn dependency:tree

This will reveal that spring-cloud-starter-netflix-eureka-server depends on spring-boot-starter-web. Once you remove the following lines from your pom.xml, your application should start up:

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency>

Source https://stackoverflow.com/questions/68587832

QUESTION

Use main Gradle project to define all dependencies versions

Asked 2022-Mar-06 at 15:38

I want to create one main Gradle project which hosts all project dependencies:

Main Gradle project:

plugins {
    id 'org.springframework.boot' version '2.6.4'
    id 'io.spring.dependency-management' version '1.0.11.RELEASE'
    id 'java'
    id 'maven-publish'
}

group = 'com.parent.dependencies'
version = '0.0.1'
sourceCompatibility = '11'

ext {
    set('springCloudVersion', "2021.0.1")
    artifactory_contextUrl = "http://192.168.1.112/repository"
}

repositories {
    mavenCentral()
    maven {
        url "${artifactory_contextUrl}/plugins-release"
        allowInsecureProtocol = true
    }
}

dependencies {
    implementation 'org.springframework.cloud:spring-cloud-starter-netflix-eureka-client'
    implementation 'org.springframework.boot:spring-boot-starter-validation'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
    implementation 'org.threeten:threetenbp:1.5.1'
    implementation 'org.springframework.boot:spring-boot-starter-actuator'
    // Lombok
    compileOnly 'org.projectlombok:lombok:1.18.22'
    annotationProcessor 'org.projectlombok:lombok:1.18.22'
    testCompileOnly 'org.projectlombok:lombok:1.18.22'
    testAnnotationProcessor 'org.projectlombok:lombok:1.18.22'
    // Swagger
    implementation group: 'io.springfox', name: 'springfox-boot-starter', version: '3.0.0'
    implementation 'org.springframework.boot:spring-boot-starter-hateoas:2.6.3'
    implementation group: 'com.netflix.hystrix', name: 'hystrix-core', version: '1.5.18'
    implementation group: 'org.springframework.security', name: 'spring-security-core', version: '5.6.1'
    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.8.2'
    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.8.2'
}

dependencyManagement {
    imports {
        mavenBom "org.springframework.cloud:spring-cloud-dependencies:${springCloudVersion}"
    }
    resolutionStrategy {
        cacheDynamicVersionsFor 0, "seconds"
        cacheChangingModulesFor 0, "seconds"
    }
}

bootJar {
    enabled = false
}

publishing {
    publications {
        mavenJava(MavenPublication) {
            from components.java
        }
    }
    repositories {
        mavenLocal()
    }
}

test {
    useJUnitPlatform()
}

Sub project which will read all dependencies versions from parent Gradle project:

plugins {
    id 'org.springframework.boot' version '2.6.4'
    id 'io.spring.dependency-management' version '1.0.11.RELEASE'
    id 'java'
    id 'maven-publish'
}

group = 'com.child'
version = '0.0.1'
sourceCompatibility = '11'

ext {
    artifactory_contextUrl = "http://192.168.1.112/repository"
}

repositories {
    mavenCentral()
    maven {
        url "${artifactory_contextUrl}/plugins-release"
        allowInsecureProtocol = true
    }
}

dependencies {
    implementation 'org.springframework.cloud:spring-cloud-starter-netflix-eureka-client'
    implementation 'org.springframework.boot:spring-boot-starter-validation'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
    implementation 'org.threeten:threetenbp'
    implementation 'org.springframework.boot:spring-boot-starter-actuator'
    // Lombok
    compileOnly 'org.projectlombok:lombok'
    annotationProcessor 'org.projectlombok:lombok'
    testCompileOnly 'org.projectlombok:lombok'
    testAnnotationProcessor 'org.projectlombok:lombok'
    // Swagger
    implementation 'io.springfox:springfox-boot-starter'
    implementation 'org.springframework.boot:spring-boot-starter-hateoas'
    implementation 'com.netflix.hystrix:hystrix-core'
    implementation 'org.springframework.security:spring-security-core'
    testImplementation 'org.junit.jupiter:junit-jupiter-api'
    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine'
}

dependencyManagement {
    imports {
        mavenBom "com.parent:com-parent-dependencies:0.0.1"
    }
}

bootJar {
    enabled = false
}

publishing {
    publications {
        mavenJava(MavenPublication) {
            from components.java
        }
    }
    repositories {
        mavenLocal()
    }
}

test {
    useJUnitPlatform()
}

When I try to compile the child project I get error:

Execution failed for task ':compileJava'.
> Could not resolve all files for configuration ':compileClasspath'.
   > Could not find org.threeten:threetenbp:.
     Required by:
         project :
   > Could not find io.springfox:springfox-boot-starter:.
     Required by:
         project :
   > Could not find com.netflix.hystrix:hystrix-core:.
     Required by:
         project :

Do you know how I can define properly the parent Gradle project with all dependencies versions and use the child project without defining dependencies versions?

ANSWER

Answered 2022-Mar-06 at 15:36

There’s a relatively new Gradle feature called “version catalogs”. With those you can centrally declare dependencies that you’d like to share between multiple projects of your build (or even between different builds).

In your concrete example, you’d add something like the following to your settings.gradle file:

dependencyResolutionManagement {
    versionCatalogs {
        libs {
            library('spring-cloud-bom', 'org.springframework.cloud:spring-cloud-dependencies:2021.0.1')
            library('spring-cloud-starter', 'org.springframework.cloud', 'spring-cloud-starter-netflix-eureka-client').withoutVersion()
            library('spring-boot-starter-validation', 'org.springframework.boot', 'spring-boot-starter-validation').withoutVersion()
            library('spring-boot-starter-test', 'org.springframework.boot', 'spring-boot-starter-test').withoutVersion()
            library('threetenbp', 'org.threeten:threetenbp:1.5.1')
            library('spring-boot-starter-actuator', 'org.springframework.boot', 'spring-boot-starter-actuator').withoutVersion()
            library('lombok', 'org.projectlombok:lombok:1.18.22')
            library('springfox-boot-starter', 'io.springfox:springfox-boot-starter:3.0.0')
            library('spring-boot-starter-hateoas', 'org.springframework.boot:spring-boot-starter-hateoas:2.6.3')
            library('hysterix-core', 'com.netflix.hystrix:hystrix-core:1.5.18')
            library('spring-security-core', 'org.springframework.security:spring-security-core:5.6.1')
            library('junit-jupiter-api', 'org.junit.jupiter:junit-jupiter-api:5.8.2')
            library('junit-jupiter-engine', 'org.junit.jupiter:junit-jupiter-engine:5.8.2')
        }
    }
}

Then, in both build.gradle files, you’d replace your dependencies blocks with the following:

dependencies {
    implementation libs.spring.cloud.starter
    implementation libs.spring.boot.starter.validation
    testImplementation libs.spring.boot.starter.test
    implementation libs.threetenbp
    implementation libs.spring.boot.starter.actuator
    // Lombok
    compileOnly libs.lombok
    annotationProcessor libs.lombok
    testCompileOnly libs.lombok
    testAnnotationProcessor libs.lombok
    // Swagger
    implementation libs.springfox.boot.starter
    implementation libs.spring.boot.starter.hateoas
    implementation libs.hysterix.core
    implementation libs.spring.security.core
    testImplementation libs.junit.jupiter.api
    testRuntimeOnly libs.junit.jupiter.engine
}

As you’re using a Maven BOM for Spring, you’ll also have to use the following updated dependencyManagement block in all projects:

dependencyManagement {
    imports {
        mavenBom libs.spring.cloud.bom.get().toString()
    }
    resolutionStrategy {
        cacheDynamicVersionsFor 0, "seconds"
        cacheChangingModulesFor 0, "seconds"
    }
}

That should be it. I could successfully test your sample build configurations with my updates at least on Gradle 7.4.

Source https://stackoverflow.com/questions/71281120

QUESTION

Configure Spring Gateway with Spring Authorization Server

Asked 2022-Jan-20 at 11:40

I have Spring Gateway application with the following Gradle dependencies:

implementation group: 'org.springframework.cloud', name: 'spring-cloud-starter-gateway'
implementation 'com.netflix.eureka:eureka-core'
implementation 'org.springframework.cloud:spring-cloud-starter-netflix-eureka-client'
implementation 'org.springframework.boot:spring-boot-starter-actuator'

Route configuration:

@Bean
public RouteLocator routes(RouteLocatorBuilder builder, LoggingGatewayFilterFactory loggingFactory) {

    return builder.routes()
            .route("service_route_clients_summary", r -> r.path("/management/home/clients/summary")
                    .filters(f -> f.rewritePath("/api/management/home/clients/summary", "/management/home/clients/summary")
                            .filter(loggingFactory.apply(new LoggingGatewayFilterFactory.Config("My Custom Message", true, true))))
                    .uri("lb://merchant-hub-admin-service:8000/management/home/clients/summary"))
            .build();
}

I want to forward /api/management/home/clients/summary to internal link /management/home/clients/summary after successful authorization with Spring Authorization Server. Is it possible to use Spring Authorization server without exposing it to outside? What is the proper way to implement this?

Code example: https://github.com/rcbandit111/Spring_Cloud_Gateway_POC

ANSWER

Answered 2022-Jan-20 at 11:40

Is it possible to use Spring Authorization server without exposing it to outside?

The Spring Authorization Server is implementing the OAuth2 protocol. If we look at the specs, we can see that it's naturally a client, which wants to authenticate itself: https://datatracker.ietf.org/doc/html/rfc6749#section-1.2. In your setup, it seems like that client is not the gateway itself, but lets say an app. So if that app should use the Spring Authorization Server, it would authenticate with it (most of the time, that means acquiring a token), before the first interaction with the gateway happens. So to answer that question, if you want to use OAuth2 as it was meant to be used, you would need a direct connection between the app and the Spring Authorization Server, which means, it needs to be exposed to the outside. This makes perfect sense, since OAuth2 is meant to be used not with a single service, but with lots of different services, e.g. to allow single-sign-on.

What is the proper way to implement this?

You could setup your own Spring Authorization Server, implement your custom Authorization Code Grant logic, so that a client can authenticate itself and acquire a token. This could for example be a JSON Web Token (JWT). This can (should) be independent from your gateway and other services.

To authorize requests at the gateway, there are different ways. You could implement a logic yourself, which reads a JWT from the request and authorize it with the Spring Authorization Server or another identity provider, which you might have. You can also use Spring Cloud Security with the Spring Authorization Server, which is described here: https://spring.io/blog/2019/08/16/securing-services-with-spring-cloud-gateway. This is definitely a proper way to implement it.

One more thing: as you can see, OAuth2 comes with a price, being that it is not trivial to understand and configure. You must understand it in detail, before you deploy such a setup. On the other hand, its a solid standard and you can have feature like single-sign-on out of the box. So if you only need authorization for single or multiple apps to a single service, there are probably easier ways to gain a token and secure an app and OAuth2 is maybe overkill. But OAuth2 really pays off, if you have lots of services and lots of apps which should be authenticated with a central (sometimes company-wide) solution.

Source https://stackoverflow.com/questions/69030184

QUESTION

Spring RestTemplate and getForObject for Microservices issues

Asked 2021-Dec-21 at 20:45

I am working on exercises from a training program regarding Microservices and Spring Boot.

I successfully configured: (1) a Eureka server, and (2) a toll rate service which is a client of the Eureka server. This toll rate service has port number 8085

Now I am trying to configure:
(3) a third service, which will be a dashboard that consume the API data from the toll rate service (and this dashboard also registers with Eureka server). This has port number 8087

The issue is that, I am not able to display the dashboard using below code for the DashboardController.java in (3):

package com.example.demo;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.client.RestTemplate;

@Controller
public class DashboardController {
    
    @RequestMapping("/dashboard")
    public String GetTollRate(@RequestParam int stationId, Model m) {
        
        RestTemplate restTemplate = new RestTemplate();
        
        TollRate tr = restTemplate.getForObject("http://localhost:8085/tollrate/" + stationId, TollRate.class);
        
        m.addAttribute("rate", tr.getCurrentRate());
        
        return "dashboard";
    }
}

This is the TollRateController.java in (2):

package com.example.demo;

import java.math.BigDecimal;
import java.time.Instant;

import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class TollRateController {
    
    @RequestMapping("/tollrate/{stationId}")
    public TollRate GetTollRate(@PathVariable int stationId) {
        
        TollRate tr;
        
        // some code to populate in-memory data
        
        return tr;
    }
}

Based on my understanding, I think the code in DashboardController.java should suffice to read data, but it just did not!

Here are some dependencies in the pom.xml in (3):

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

Below are the error messages when I tried to refresh the dashboard page: http://localhost:8087/dashboard?stationId=1

2021-12-20 19:53:16.911[0;39m [31mERROR[0;39m [35m4608[0;39m [2m---[0;39m [2m[nio-8087-exec-1][0;39m [36mo.a.c.c.C.[.[.[/].[dispatcherServlet]   [0;39m [2m:[0;39m Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.thymeleaf.exceptions.TemplateInputException: Error resolving template [dashboard], template might not exist or might not be accessible by any of the configured Template Resolvers] with root cause

org.thymeleaf.exceptions.TemplateInputException: Error resolving template [dashboard], template might not exist or might not be accessible by any of the configured Template Resolvers
    at org.thymeleaf.engine.TemplateManager.resolveTemplate(TemplateManager.java:869) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
    at org.thymeleaf.engine.TemplateManager.parseAndProcess(TemplateManager.java:607) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
    at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1098) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
    at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1072) ~[thymeleaf-3.0.12.RELEASE.jar:3.0.12.RELEASE]
    at org.thymeleaf.spring5.view.ThymeleafView.renderFragment(ThymeleafView.java:366) ~[thymeleaf-spring5-3.0.12.RELEASE.jar:3.0.12.RELEASE]
    at org.thymeleaf.spring5.view.ThymeleafView.render(ThymeleafView.java:190) ~[thymeleaf-spring5-3.0.12.RELEASE.jar:3.0.12.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1400) ~[spring-webmvc-5.3.13.jar:5.3.13]
    at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1145) ~[spring-webmvc-5.3.13.jar:5.3.13]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1084) ~[spring-webmvc-5.3.13.jar:5.3.13]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963) ~[spring-webmvc-5.3.13.jar:5.3.13]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.13.jar:5.3.13]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.3.13.jar:5.3.13]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:655) ~[tomcat-embed-core-9.0.55.jar:4.0.FR]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.13.jar:5.3.13]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) ~[tomcat-embed-core-9.0.55.jar:4.0.FR]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.55.jar:9.0.55]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.13.jar:5.3.13]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.13.jar:5.3.13]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.13.jar:5.3.13]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.13.jar:5.3.13]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:96) ~[spring-boot-actuator-2.6.1.jar:2.6.1]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.13.jar:5.3.13]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.13.jar:5.3.13]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.13.jar:5.3.13]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:540) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:382) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:895) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1722) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.55.jar:9.0.55]
    at java.base/java.lang.Thread.run(Thread.java:833) ~[na:na]

Please let me know if you have any thoughts, thank you.

ANSWER

Answered 2021-Dec-21 at 20:45

According to the described setup, particularly:

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>

...and the exception detail:

org.thymeleaf.exceptions.TemplateInputException: 
  Error resolving template [<viewname>], template might not
  exist or might not be accessible by any of the configured Template Resolvers

It looks like we "just forgot" to place (with default setup) a <viewname>.html in our src/main/resources/templates folder.

References

Source https://stackoverflow.com/questions/70429963

QUESTION

How to install nc in mysql container

Asked 2021-Dec-18 at 18:01

I am getting this message nc command is missing and by doing some R&D, I got to know that in order to resolve this, (I think) I need to run below command in MySQL container in docker-compose

RUN apt-get -q update && apt-get -qy install netcat

But the issue is I don't have it's docker file else I could have written this command in docker file and might have called docker file from docker-compose

Does anyone have any idea how can I run this command from docker-compose?

Edit 1: I have made separate the DockerFile for mysql which consists of

FROM mysql:8
RUN apt-get -q update && apt-get -qy install netcat
COPY wait-for.sh .

and then called this docker file from docker-compose which goes like this...

version: "3"
services:
    mysql-standalone:
        image: mysql:8.0.25
        environment:
            - MYSQL_ROOT_PASSWORD=********
            - MYSQL_DATABASE=usermanagementappdp
        ports:
            - 3306:3306
        depends_on: ['eureka-server']
        build:
            context: "./mysqlDockerFile2"
            dockerfile: "Dockerfile"
        volumes:
            - ./wait-for:/docker-entrypoint-initdb.d
        entrypoint: ["/docker-entrypoint-initdb.d/wait-for.sh", "eureka-server:8761", "--", "docker-entrypoint.sh"]

    phpmyadmin:
        image: phpmyadmin/phpmyadmin:latest
        restart: always
        environment:
            PMA_HOST: mysql-standalone
            PMA_USER: root
            PMA_PASSWORD: root123M.
        ports:
            - 8085:80

    eureka-server:
        image: eureka-server
        ports:
            - 8761:8761
        build:
            context: "../Eureka-Server-For-User-Management-App"
            dockerfile: "Dockerfile"


    usermanagementapp-docker:
        image: usermanagementapp-docker:latest
        ports:
            - 8089:8089
        links:
            - eureka-server
        environment:
            EUREKA_CLIENT_SERVICEURL_DEFAULTZONE: http://eureka-server:8761/eureka
            SPRING_DATASOURCE_URL: jdbc:mysql://mysql-standalone:3306/usermanagementappdp?allowPublicKeyRetrieval=true&autoReconnect=true&useSSL=false
        build:
            context: "./"
            dockerfile: "Dockerfile"
        restart: on-failure
        entrypoint: ["/wait-for.sh", "mysql-standalone:3306", "--", "['java','-jar','/app.jar']"]
        depends_on: ['mysql-standalone','eureka-server']

Docker file for User management app is:

FROM openjdk:8
Add target/User-Management-App-0.0.1-SNAPSHOT.jar app.jar
VOLUME /tmp
EXPOSE 8089
RUN apt-get -q update && apt-get -qy install netcat
COPY wait-for.sh .
COPY target/User-Management-App-0.0.1-SNAPSHOT.jar app.jar
ENTRYPOINT ["java","-jar","/app.jar"]

Docker file for Eureka- server

FROM openjdk:8
EXPOSE 8761
ADD /target/Eureka-Server-For-User-Management-App-0.0.1-SNAPSHOT.jar netflix-eureka-server-1.0.jar
COPY wait-for.sh .
netflix-eureka-server-1.0.jar
ENTRYPOINT ["java","-jar","netflix-eureka-server-1.0.jar"]

Edit 2 I just edited mysql docker file to check if it is even getting executed or not

RUN echo "'Entered in docker file of mysql'"
FROM mysql:8
RUN apt-get -q update && apt-get -qy install netcat
COPY wait-for.sh .

RUN echo "'Exiting docker file of mysql'"

and found that on doing docker-compose up it is not echoing the text

ANSWER

Answered 2021-Dec-17 at 06:33

You could build and publish your own container image if you wanted with a dockerfile like this

FROM mysql:8
RUN apt-get -q update && apt-get -qy install netcat

and build it like docker build . -t user123/mysql:8

and push it like docker push user123/mysql:8

then switch your docker compose to use your custom container.

if you just need to pop in temporarily to install netcat, you can do that by doing

docker exec -it --user=root ContainerHashOrName /bin/bash where ContainerHashOrName can be retrieved from docker ps then just run your commands like you would on any other distro. Just be aware that you are only making changes to the specific instance of a container and that any rescheduling will bring up a different instance of the container.

Source https://stackoverflow.com/questions/70389175

QUESTION

How to make a proper reactive extension on Eureka SelectableSection

Asked 2021-Dec-01 at 03:28

This is my first question to the StackOverflow community so excuse me if I'm doing something wrong.

1. What I'm trying to achieve
Basically, I want to make a custom reactive wrapper around Eureka's SelectableSection class in order to observe the value of the selected row when it is changed. I'm thinking to get this data from the onSelectSelectableRow closure which is called every time a row is selected.

2. What I've tried to do for that
Actually, I've got this working but it's not a generic use of the custom wrapper, here is the example that works but only when I specify the row and its value type, for example ListCheckRow<Int>.

extension SelectableSection: ReactiveCompatible {}
extension Reactive where Base : SelectableSection<ListCheckRow<Int>> {
  var selectedValue: Observable<Base.SelectableRow.Cell.Value?> {
    return Observable.create { observer in
      self.base.onSelectSelectableRow = {cell, row in
        observer.onNext(row.value)
      }
      return Disposables.create {
        observer.onCompleted()
      }
    }
  }
}

This works fine and as I expected but when it comes to something more generic like the next code example, I get an error saying that: "Cannot assign to property: 'base' is a 'let' constant"

extension SelectableSection: ReactiveCompatible {}
extension Reactive where Base : SelectableSectionType {
  var selectedValue: Observable<Base.SelectableRow.Cell.Value?> {
    return Observable.create { observer in
      self.base.onSelectSelectableRow = {cell, row in // Error: Cannot assign to property: 'base' is a 'let' constant
        observer.onNext(row.value)
      }
      return Disposables.create {
        observer.onCompleted()
      }
    }
  }
}

Any help will be much appreciated, thanks. 🙏

ANSWER

Answered 2021-Dec-01 at 03:28

The fundamental problem here is that SelectableSectionType is a protocol that isn't restricted to class types and Reactive assumes that Base is a class (or otherwise is not going to be modified by the observable creation.)

I think the most generic you can make this is something like:

extension Reactive {
    func selectedValue<Row, T>() -> Observable<T?> where Base: SelectableSection<Row>, Row: SelectableRowType, T == Row.Cell.Value  {
        Observable.create { [base] observer in
            base.onSelectSelectableRow = { cell, row in
                observer.onNext(row.value) // this is problematic. See below.
            }
            return Disposables.create {
                observer.onCompleted() // this is wrong. See below.
            }
        }
    }
}

The biggest problem with the above though is that if you subscribe to the resulting Observable more than once or create more than one Observable using this computed property, all but the last subscription will silently fail. The simple way to fix this is to always remember to share any result but that's rather error prone.

The way to fix this would be to associate a Subject with each SelectableSection, but you can't modify the class, so what are we to do?

Here's a solution:

extension Reactive {
    func selectedValue<Row, T>() -> Observable<T?> where Base: SelectableSection<Row>, Row: SelectableRowType, T == Row.Cell.Value  {
        Observable.create { [base] observer in
            if let block = selectableSections.first(where: { $0.section === base }) {
                let subject = block.subject as! PublishSubject<T?>
                return Disposables.create(
                    block.disposable.retain(),
                    subject.subscribe(observer)
                )
            }
            else {
                let subject = PublishSubject<T?>()
                let block = SelectableSectionBlock(
                    section: base,
                    subject: subject,
                    disposable: RefCountDisposable(disposable: Disposables.create {
                        selectableSections.removeAll(where: { $0.section === base })
                    })
                )
                base.onSelectSelectableRow = { cell, row in
                    subject.onNext(row.value)
                }
                selectableSections.append(block)
                return Disposables.create(
                    block.disposable,
                    subject.subscribe(observer)
                )
            }
        }
    }
}

private struct SelectableSectionBlock {
    let section: Section
    let subject: Any
    let disposable: RefCountDisposable
}

private var selectableSections = [SelectableSectionBlock]()

The selectableSections array stores a Subject and RefCountDisposable for each SelectableSection.

Whenever an Observable is created, or subscribed to...

if it's the first time working with this section, it will create a Subject and RefCountDisposable assign the onSelectSelectableRow to send a next event to the subject and store the subject in the array.
otherwise it will find the subject and disposable associated with this Section and retain the disposable.

Once it has the subject and disposable from above, it will subscribe the new observer to the subject and return a new Disposable that will remove that subscription and decrement the ref-count when the time comes.

Yes this is quite a bit more complex than the simple assignment case, but it's the right thing to do.

As for calling onCompleted() inside the disposable closure. By the time the closure is called, the observer has already emitted an onCompleted/onError event, or the observer has stopped listening to the observable. So this event will never be seen.

Source https://stackoverflow.com/questions/70176783

QUESTION

Issue selecting multiple inputs using selectInput

Asked 2021-Nov-19 at 22:14

So I put together the foundation of this scrip thanks to the help of an older question I posted on here.

But when I try to add multiple inputs by specifying selectInput(multiple = TRUE...) and then changing all the = on the server side to %in% to account for the multiple choices, I am met with the following error:

Warning: Error in if: argument is of length zero [No stack trace available]

library(shiny)
library(DT)

State <- c("NV", "NV","NV", "MD", "MD", "MD", "MD", "NY", "NY", "NY", "OH", "OH", "OH")
County <- c("CLARK", "WASHOE", "EUREKA", "MONTGOMERY", "HOWARD", "BALTIMORE", "FREDERICK", "BRONX", "QUEENS", "WESTCHESTER", "FRANKLIN", "SUMMIT", "STARK" )
City <- c("Las Vegas", "Reno", "Eureka", "Rockville", "Columbia", "Baltimore", "Thurmont", "Bronx", "Queens", "Yonkers", "Columbus", "Akron", "Canton")
Rating<- c(1,2,3,4,5,6,7,8,9,10,11,12,13)
df <- data.frame(State, County, City, Rating, stringsAsFactors = F)

ui <- fluidPage(
  titlePanel("Test Dashboard "),
  sidebarLayout(
    sidebarPanel(
      selectInput("data1", "Select State", choices = c("All", unique(df$State))),
      selectInput("data2", "Select County", choices = NULL, multiple = TRUE),
      selectInput("data3", "select City", choices = NULL, multiple = TRUE)
    ),
    mainPanel(
      DTOutput("table")
    )
  ))

server <- function(input, output, session){
  
  observeEvent(input$data1, {
    if (input$data1 != "All") {
      updateSelectInput(session, "data2", "Select County", choices = c("All", unique(df$County[df$State %in% input$data1])))
    } else {
      updateSelectInput(session, "data2", "Select County", choices = c("All", unique(df$County)))
    }
  }, priority = 2)
  
  observeEvent(c(input$data1, input$data2), {
    if (input$data2 != "All") {
      updateSelectInput(session, "data3", "Select City", choices = c("All", unique(df$City[df$County %in% input$data2])))
    } else {
      if (input$data1 != "All") {
        updateSelectInput(session, "data3", "Select City", choices = c("All", unique(df$City[df$State %in% input$data1])))
      } else {
        updateSelectInput(session, "data3", "Select City", choices = c("All", unique(df$City)))
      }
    }
  }, priority = 1)
  
  filtered_data <- reactive({
    temp_data <- df
    if (input$data1 != "All") {
      temp_data <- temp_data[temp_data$State %in% input$data1, ]
    }
    if (input$data2 != "All") {
      temp_data <- temp_data[temp_data$County %in% input$data2, ]
    }
    if (input$data3 != "All") {
      temp_data <- temp_data[temp_data$City %in% input$data3, ]
    }
    temp_data
  })
  
  output$table <- renderDT(
    filtered_data()
  )
  
}

shinyApp(ui, server)

ANSWER

Answered 2021-Nov-19 at 22:14

You just need req(), in a couple of places. Try this

server <- function(input, output, session){
  
  observeEvent(input$data1, {
    if (input$data1 != "All") {
      updateSelectInput(session, "data2", "Select County", choices = c("All", unique(df$County[df$State %in% input$data1])))
    } else {
      updateSelectInput(session, "data2", "Select County", choices = c("All", unique(df$County)))
    }
  }, priority = 2)
  
  observeEvent(c(input$data1, input$data2), {
    req(input$data2)
    if (input$data2 != "All") {
      updateSelectInput(session, "data3", "Select City", choices = c("All", unique(df$City[df$County %in% input$data2])))
    } else {
      if (input$data1 != "All") {
        updateSelectInput(session, "data3", "Select City", choices = c("All", unique(df$City[df$State %in% input$data1])))
      } else {
        updateSelectInput(session, "data3", "Select City", choices = c("All", unique(df$City)))
      }
    }
  }, priority = 1)
  
  filtered_data <- reactive({
    temp_data <- df
    req(input$data2,input$data3)
    if (input$data1 != "All") {
      temp_data <- temp_data[temp_data$State %in% input$data1, ]
    }
    if (input$data2 != "All") {
      temp_data <- temp_data[temp_data$County %in% input$data2, ]
    }
    if (input$data3 != "All") {
      temp_data <- temp_data[temp_data$City %in% input$data3, ]
    }
    temp_data
  })
  
  output$table <- renderDT(
    filtered_data()
  )
  
}

Source https://stackoverflow.com/questions/70041008

Community Discussions, Code Snippets contain sources that include Stack Exchange Network

Vulnerabilities

No vulnerabilities reported

Install eureka

You can download it from GitHub, Maven.
You can use eureka like any standard Java library. Please include the the jar files in your classpath. You can also use any IDE and you can run and debug the eureka component as you would do with any other Java program. Best practice is to use a build tool that supports dependency management such as Maven or Gradle. For Maven installation, please refer maven.apache.org. For Gradle installation, please refer gradle.org .

Support

Please see [wiki](https://github.com/Netflix/eureka/wiki) for detailed documentation.

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