CODEWITHSUNDEEP
dockersocketscurldocker-composedocker-api
user12934448
user12934448

Reputation: 11

Docker API not accessible from within a container

I can make cUrl calls to Docker API but if I run the same script from a container (docker-compose), I can't reach any API endpoint.

My requests looks like :

$ curl --unix-socket /var/run/docker.sock -X POST http:/localhost/containers/json

The reason could be the use of localhost but I can't find the solution for now. Any suggestions?

EDIT : Here's a brief summary of the stack i'm using (Api-Platform https://api-platform.com/). Every container is attached to an "api_default" bridge network :

I do have a shell script in my "php" container which is meant to reach the Docker API. To summarize, I request the "mssql" container to sync with an external service and then I ask to "psql" container to copy those datas (export/import done with csv files through shared volumes).

The problem is :

Below is a part of my script :

curl -XPOST -H 'Content-Type: application/json' \
      --unix-socket /var/run/docker.sock http:/localhost/containers/mssql/exec \
      -d '{
        "AttachStdout":true,
        "Tty":true,
        "Cmd":["/opt/mssql-tools/bin/sqlcmd", ...]
      }'

And here is the way I call my Symfony command in the api endpoint Controller :

 /**
  * @Route("/api/sync", name="sync", methods={"GET"})
  */
  public function sync(KernelInterface $kernel)
  {
    $application = new Application($kernel);
    $application->setAutoExit(false);

    $input = new ArrayInput(array(
        'command' => 'app:sync'
    ));

    $output = new BufferedOutput();
    $application->run($input, $output);
    $content = $output->fetch();

    return new Response($content);
  }

Maybe should I replace "localhost" with "api_default" to reach the good network, but that doesn't work ... ?

Upvotes: 1

Views: 3032

Answers (2)

Eric McLachlan
Eric McLachlan

Reputation: 3530

Yep. If you want to communicate between one docker container and another docker container, at the very least, you need to use the service name instead of localhost because, as @BMW said, localhost is relative to the machine you are on, and from the container's point of view, localhost is the container itself.

I had a similar situation recently where it wasn't enough to use the service name. I also had to create a network and add each service to that network. Like this:

my_service:
    ...
    ...
    ...
    networks:
      - backend

networks:
  backend:
    driver: bridge

Upvotes: 1

BMW
BMW

Reputation: 45243

the localhost you try to connnect is the localhost in the container you run curl

you should find and replace with its host ip

Upvotes: 1

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