wait-for-it | Wait for service to be | TCP library

Solution is to utilise HEALTHCHECK [OPTIONS] CMD command

The command after the CMD keyword can be either a shell command (e.g. HEALTHCHECK CMD /bin/check-running) or an exec array (as with other Dockerfile commands; see e.g. ENTRYPOINT for details).

The command’s exit status indicates the health status of the container. The possible values are:

0: success - the container is healthy and ready for use

1: unhealthy - the container is not working correctly

2: reserved - do not use this exit code

Probably you can create some shell script

Answering my own question as I have FINALLY found the cause of all my troubles ...

I had created an __init__.py file at the root of my project to define a project version as a constant..

After reading here and there about Django modules and namespaces, I removed the __init__.py from my root directory and that solved the problem.

**edited my question above to show the file in question

I fixed it!

This is really silly, but OS X doesn't like the "$container" so if you explicitly just write the name of container for the database, it works like a charm!

I have got one solution .. that at the first line of the docker file, I will first decleare the 'FROM alpine:3.7', and then inside the docker file I will keep adding the required runtimes and the dependent libraries accordingly. This way we can add mutiple runtimes.

Below the working docker compose where I have commented out both the lines for openjdk and python runtime and added FROM alpine:3.7: Also some trick to add asyncpg library to the python runtime. This way I can now add any dependencies. I can now work on asyncpg.

-------- Docker file ----------------

The compose file you have isn't an image itself; its a means to manage a collection of images. This mean you wouldn't upload the docker-compose file itself to dockerhub, but rather the images for each service. 'Deploying' a docker-compose file is (generally) a matter of copying the docker-compose file to your server and running docker-compose up -d (or making a service that automates this, perhaps with systemd). Any image in the compose file will be pulled automatically.

For your specific compose file, you are defining the images locally for the nginx service and the app service, in which case you have two options:

1. Copy ./nginx and/or ./app to your server and run the compose file as-is. This will build the image locally when you call docker-compose and skip uploading it to dockerhub
2. run docker build ./app -t yourtag (and same for ./nginx if desired) and push to dockerhub with docker push yourimage:yourtag. In that case you would need to edit the compose file to pull the images and tags you defined when building them.

To wait-for-it.sh is pooling the resources exposed from for the container and waits for the resource to became available (ip address, exposed port, or both).

Following is a canonical approach with python and docker-py (docker's own python library) which will help you to orchestrate your containers even better.

First we import the packages that we need and crate a client to the docker engine

The problem is likely to be in ECONNREFUSED 0.0.0.0:9324. Judging by the port number it is an attempt to reach the sqs service, but the IP-address is bad. It should connect to sqs:9324 or an IP-address of that container. 0.0.0.0 means 'any IP-address' and it is usually used to bind a port. Check your serverless configuration.

Also, you can easily check if you are in a 'race condition' or not. For that simply start your services one by one using several terminals:

There's a bridge (by default in Docker Compose) between your services, and you can access to another service by :, so you can access hub service by hub:4444.

From the official Docker Compose documentation, as you can read here:

You can control the order of service startup and shutdown with the depends_on option. Compose always starts and stops containers in dependency order, where dependencies are determined by depends_on, links, volumes_from, and network_mode: "service:...".

As you did with depends_on, but

However, for startup Compose does not wait until a container is “ready” (whatever that means for your particular application) - only until it’s running. There’s a good reason for this.

Use a tool such as wait-for-it, dockerize, sh-compatible wait-for, or RelayAndContainers template. These are small wrapper scripts which you can include in your application’s image to poll a given host and port until it’s accepting TCP connections.

They suggest you to act like this:

Look at this minimal example: