varnish | varnish | Caching library
kandi X-RAY | varnish Summary
kandi X-RAY | varnish Summary
varnish.js is a library to help with the management of varnish servers. Note: This library only targets Varnish 3.x and above. For clarity on the feature please refer to the documentation.
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QUESTION
I built a Varnish VMOD that defines an object, which is instantiated in vcl_init and is always kept in memory, and used in individual requests.
My configuration is split up in several VCL files, that get loaded from a "master" VCL depending on some request parameters.
The master VCL also instantiates the object in question, which I want to use in another VCL. The reason why I don't instantiate the object in the same VCL I use it in, is that I have another VCL that defines some ACL-restricted routes to update the object from a data source.
E.g. master.vcl:
ANSWER
Answered 2021-Jun-10 at 14:38You can't do this with objects directly as they are scoped by the VCL and can't "escape" it. As you've experienced, you need to load the labeled vcl first, so you also need to create the object in it.
But nothing prevents you from creating objects that reference a global variable so all objects have access to the same data.
Alternatively, you can use the Event function to use a PRIV_VCL (https://stackoverflow.com/a/60753085) also referencing a global pointer and avoid using objects completely. This is what is done here for example: https://github.com/varnish/varnish-modules/blob/master/src/vmod_vsthrottle.c#L345
QUESTION
I need to do cache key generation/store based on the response header received from the backend not based on the URL requested from the client-side.
The main reason for doing so is: I have a backend logic to reply to the client with some different data if requested things are not available.
Ex:
Request: example.com/foo/102030?names=test1
now, my backend checks for is test1 is present for 102030, if not it checks whether 102030 has a special tag = Y : basically tells that have to look for some other matching object.
so, in that case, backed reply's to clients with data again, which can be accessible with example.com/foo/000000?names=test1.
So, now the problem is if some other request comes with example.com/foo/000000?names=test1, varnish considers this as a different request based on URL but in actuality, I need to serve the same data which is already present in Cache with example.com/foo/000000?names=test1.
Currently, I do Ban using some regex syntax from the backend, so in that case, I can easily invalidate the object which stored with /foo/000000?names=test1 not the other one.
So, is there a way through which I can store the cache key based on the response header info?
...ANSWER
Answered 2021-Jun-10 at 12:48There's no way you can do this unfortunately. Only request information can be used to create the cache key.
That is by design, because incoming requests only have their own request properties they can present to Varnish to identify the resource they wish to retrieve.
QUESTION
Consider my requested url is www.example.com/foo/emplooyee?names = test1;test2. and varnish stores this entire URL along with query parameters to uniquely identify the cache.
now, in my backend, I'm running one service and which I'm supposed to configure as whenever there are changes in names (i.e. test1 or test2) is should fire an HTTP ban with an older name (single name at a time in ban expression) to invalidate all the cached URL which entered with similar names.
Questions: My client request url could be like this,
- www.example.com/foo/emplooyee?names = test1;test2
- www.example.com/foo/emplooyee?names = test1;
- www.example.com/foo/emplooyee?names = test2;test1;test3;test4
- www.example.com/foo/emplooyee?names = test1;test4.
How to write a VCL code and in Ban expression to invalidate all object which has query parameter as test1?
...ANSWER
Answered 2021-Jun-08 at 06:52This is the VCL code you need for banning:
QUESTION
I have a scenario where my URL will be either contains a comma delimiter with value or without. i.e. /api/parameters/XXXXXXXXXX?tables=x0 or tables=x0;x1;x2.
now based on this URL I want to check in the varnish that, if URL contains multiple values as tables then separate that out and pass each table name in seperate URL (/api/parameters/XXXXXXXXXX?tables=x0, /api/parameters/XXXXXXXXXX?tables=x1, /api/parameters/XXXXXXXXXX?tables=x2) either to cache if miss then backend server.
then based on the response of this need to combine the result and return it to the client. my question here is:
- How to segregate the value from the URL and pass a modified URL to varnish cache or backend.
- after returning the result I want to return it as a combined JSON object in a sequence of which it was originally requested with a comma delimiter(i.e. x0 result;x1 result;x2 result).
ANSWER
Answered 2021-May-31 at 15:39It is possible to turn a single request into multiple subrequests in Varnish. Unfortunately this cannot be done with the open source version, only with the Enterprise version.
vmod_httphttps://docs.varnish-software.com/varnish-cache-plus/vmods/http/ describes how you can perform HTTP calls from within Varnish using vmod_http.
By sending HTTP requests to other URLs through Varnish, you can get multiple objects out of the cache and aggregate them into a single response
No loopingThe fact that Varnish doesn't have loops makes matters a bit more complicated. You'll have so set an upper limit to the amount of values the tables querystring parameter has and you'll have to check the values using individual if-statements.
Once you have fetched the results from the various URLs, you can create a JSON string and return it via return(synth(200,req.http.json)). Where req.http.json contains the JSON string.
This will create a synthetic response.
In Varnish Enterprise it is also possible to cache synthetic output. See https://docs.varnish-software.com/varnish-cache-plus/vmods/synthbackend/ to learn more about vmod_synthbackend.
The solution I suggested in my answer uses Varnish Enterprise, the commercial version of Varnish. It extends Varnish capabilities with additional VMODs and features, which you can read about here. One easy way to try it out without upfront licensing payments, if you’re interested, is to spin up an instance on cloud infrastructure:
QUESTION
I need to decode JSON encoded data of php in JavaScript. I am giving php code below:
...ANSWER
Answered 2021-May-18 at 08:33I think what you're looking for is JSON.parse()
QUESTION
I am trying to setup a varnish cache where the varnish instance is hosted on one server and the backend is on a different server. They are both on aws lightsail instances. The issue I am having is when I try and go to the site, I get the Error 503 Backend fetch failed
error. Here is the varnish default.vcl:
ANSWER
Answered 2021-May-07 at 08:19I discovered the key information in the logs:
QUESTION
I'm using Varnish to cache Laravel pages.
In order to display different CSRF Tokens for everyone, I use ESI to exclude CSRF from cache :
app.blade.php
...ANSWER
Answered 2021-Apr-05 at 15:58I'm afraid your VCL file has some issues. Not just in regards to the CSRF token, but also in regards to conventional caching behavior. Some of the basic rules of the [built-in VCL][1] are disregarded in your configuration.
The Laravel documentation states that the CSRF token should match the value in the session data. However, your vcl_backend_response logic removes the Set-Cookie header almost unconditionally.
I believe we're going to need both the Set-Cookie response header and the Cookie request header to make sure the Laravel session remains active.
Before we can write the proper VCL code, we need to make sure we understand the business logic behind CSRF tokens.
According to https://github.com/laravel/framework/blob/0d601f598a2434b8b126c06af75a0f089b10a102/src/Illuminate/Session/Store.php#L614-L617 the token is random string of 40 characters.
At first sight, the token seems to be unique per session and not per request. This means we can cache them as long as we have a cache variation per session.
Passing the CSRF token during a POST callhttps://laravel.com/docs/8.x/csrf states that CSRF tokens can be passed in 2 ways:
- Through a
_tokenpost field - Through a
X-CSRF-TOKENrequest header
If you're planning to use a post field, this is what you're going to add:
QUESTION
On the command line, I can do a request like: curl -I -H "Fastly-Debug: 1"
and it will return a lot of helpful information from the CDN serving that URL, in this case, Fastly:
...ANSWER
Answered 2021-Apr-30 at 22:51The -H (header) flag allows you to specify a custom header in cURL. Your code already does this - great! All that's left is emulating the -I (head) flag.
From cURL manpage for the -I option:
Fetch the headers only! HTTP-servers feature the command HEAD which this uses to get nothing but the header of a document.
To use the HEAD method, you need to specify it instead of GET:
QUESTION
I have an HaProxy that accept-proxy connection
...ANSWER
Answered 2021-Apr-22 at 10:12The way you configured your HAProxy allows incoming connections to use the PROXY protocol.
What you need to do is configure HAProxy to connect to the backend over the PROXY protocol.
It's just a matter of adding send-proxy-v2 to your server definition as illustrated below:
QUESTION
This question is regarding getting Xdebug to work with a CLI PHP script hosted inside a web-server Docker instance.
I have docker containers : web-server, varnish-cache, nginx-proxy.
I am able to successfully debug a Magento 2 web-page via browser with this VS Code Launch config:
This is with the new XDebug v3 which removed alot of v2 configuration settings
Client (Windows 10) IP (my laptop) : 192.168.1.150, Host (Ubuntu 20.04) IP: 192.168.1.105, hosting with Docker containers IP: 172.100.0.2-5
VS Code launch:
...ANSWER
Answered 2021-Mar-26 at 12:49You need to set Xdebug's xdebug.client_host to the IP address of your IDE, which you indicated is 192.168.1.150.
You also need to turn off xdebug.discover_client_host, as that would try to use the internal Docker network IP (172.100.0.2), which is not where your IDE is listening on.
Remember: Xdebug makes a connection to the IDE, not the other way around.
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