GitLab CI: how to connect to the docker container started in .gitlab-ci.yml script?

问题

Initial task

In my GitLab CI build, I want to:

Start a docker container with local AmazonDB. Standard port layout: port 8000 in docker, port 8000 exposed. Of course, everything works locally, I can connect (curl, awc-cli, Java code for Amazon DB, whatever you wish).
Use it for tests, i.e. connect to it as --endpoint-url http://localhost:8000 (or any other mapped IP instead of localhost).

Problem

.gitlab-ci.yml looks like this:

image: docker:stable

build/test:
  tags:
    - gradle
    - eu

  stage: test

# doesn't work with or without it
#  services:
#    - docker:dind

  script:
    # display local running containers
    - echo Displaying all running docker containers with "amazon/dynamodb-local" image...
    - docker ps --filter ancestor=amazon/dynamodb-local

    # stop all running docker containers with "amazon/dynamodb-local" image
    - echo Stopping all Docker containers with "amazon/dynamodb-local" image...
    - CONTAINERS=$(docker ps -q --filter ancestor=amazon/dynamodb-local)
    - >
      if [ "${CONTAINERS}" == "" ]; then
        echo No docker containers with "amazon/dynamodb-local" image running. Nothing to stop.
      else
        docker stop $(docker ps -q --filter ancestor=amazon/dynamodb-local)
        echo All Docker containers with "amazon/dynamodb-local" image stopped.
      fi

    # start DynamoDB local as a docker container with shared database
#    - java -Djava.library.path=./dynamodb_local_latest/DynamoDBLocal_lib -jar ./dynamodb_local_latest/DynamoDBLocal.jar -sharedDb
    # relative path to causes "Error: Unable to access jarfile" for both windows and linux
    # run Docker in detached mode to not hang on the opened console
    - cd ./dynamodb_local_latest
    - docker run --detach -p 8000:8000 amazon/dynamodb-local -jar DynamoDBLocal.jar -sharedDb
    - cd ./..

    # display local running containers
    - echo Displaying all running docker containers with "amazon/dynamodb-local" image...
    - docker ps --filter ancestor=amazon/dynamodb-local

    # see https://stackoverflow.com/questions/45389116/unable-to-access-docker-compose-containers-created-inside-docker
    # $DOCKER_HOST is unix:///var/run/docker.sock
    # http://localhost:8080 fails
    # http://docker:8000 fails
    # http://unix:///var/run/docker.sock:8000 fails
    - echo docker host is ${DOCKER_HOST}
    - cat /etc/hosts
#    - curl docker:80 | true
#    - curl docker:8000 | true
#    - curl http://docker:8000 | true
#    - curl http://docker:8000 | true
#    - curl ${DOCKER_HOST} | true
#    - curl ${DOCKER_HOST}:8000 | true
    - curl localhost:8000 | true
    - curl http://localhost:8000 | true

    # stop all running docker containers with "amazon/dynamodb-local" image
    - echo Stopping all Docker containers with "amazon/dynamodb-local" image...
    - CONTAINERS=$(docker ps -q --filter ancestor=amazon/dynamodb-local)
    - >
      if [ "${CONTAINERS}" == "" ]; then
        echo No docker containers with "amazon/dynamodb-local" image running. Nothing to stop.
      else
        docker stop $(docker ps -q --filter ancestor=amazon/dynamodb-local)
        echo All Docker containers with "amazon/dynamodb-local" image stopped.
      fi

    # display local running containers
    - echo Displaying all running docker containers with "amazon/dynamodb-local" image...
    - docker ps --filter ancestor=amazon/dynamodb-local

Critical execution points (Gitlab-CI log) look like this:

Docker container runs:

$ docker run --detach -p 8000:8000 amazon/dynamodb-local -jar DynamoDBLocal.jar -sharedDb
c823489c22fffa603c1ae1b91d898cb7de4964774d54a08c9fdf0b891c2243b4
$ echo Displaying all running docker containers with "amazon/dynamodb-local" image...
Displaying all running docker containers with amazon/dynamodb-local image...
$ docker ps --filter ancestor=amazon/dynamodb-local
CONTAINER ID        IMAGE                   COMMAND                  CREATED             STATUS                  PORTS                    NAMES
c823489c22ff        amazon/dynamodb-local   "java -jar DynamoDBL…"   1 second ago        Up Less than a second   0.0.0.0:8000->8000/tcp   peaceful_beaver

curl fails (tried all possible variations, this is just an example):

$ curl localhost:8000 | true
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed

  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
curl: (7) Failed to connect to localhost port 8000: Connection refused
Authenticating with credentials from $DOCKER_AUTH_CONFIG
ERROR: Job failed: exit code 7

I tried with and without

  services:
    - docker:dind

Tried with host names localhost or docker or tcp://localhost, with http:// prefix or without it, with ports 80, 8000 or 2375. Nothing works.

Value of ${DOCKER_HOST} is unix:///var/run/docker.sock:

$ echo docker host is ${DOCKER_HOST}
docker host is unix:///var/run/docker.sock

/etc/hosts does not contain an alias for docker

$ cat /etc/hosts
127.0.0.1   localhost
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
172.17.0.3  runner-H3HL9s9t-project-913-concurrent-0

Questions

How to solve this typical task?
Is it solvable with docker run, or complex docker-compose usage required.
Is there a link to a working example?
Is it a problem, that there is no docker alias in /etc/hosts?
Is unix:///var/run/docker.sock a valid value of ${DOCKER_HOST}? Shouldn't the value for this variable be set in variables of .gitlab-ci.yml (particularly to tcp://localhost:2375)?

Links

There are multiple links that I've googled. Solutions from there haven't helped me for now.

https://gitlab.com/gitlab-com/support-forum/issues/748
https://gitlab.com/gitlab-org/charts/gitlab/issues/478
https://blog.lwolf.org/post/how-to-build-and-test-docker-images-in-gitlab-ci/
https://gitlab.com/gitlab-org/gitlab-foss/issues/26566 — similar issue, for docker-compose
https://gitlab.com/gitlab-org/gitlab-foss/issues/40774 — exactly the same issue
Gitlab CI runner not able to expose ports of nested Docker containers
Unable to access docker-compose containers created inside docker

回答1:

There is actually no need in writing such a complex solution with manual docker run / docker stop inside the -script section. The slim and simple way is to use the local DynamoDB as service.

With this script, local DynamoDB will be accessible via url from alias, i.e. dynamodb-local for this example:

  services:
    - name: amazon/dynamodb-local
      alias: dynamodb-local

Executing aws dynamodb with http://dynamodb-local:8000 endpoint url works:

  script:
    - DYNAMODB_LOCAL_URL=http://dynamodb-local:8000
    - apk add --no-cache curl jq python py-pip
    - pip install awscli
    - aws dynamodb list-tables --endpoint-url ${DYNAMODB_LOCAL_URL} --region eu-central-1

This option was found in this great answer. Many thanks to @madhead for providing it!

来源：https://stackoverflow.com/questions/60326823/gitlab-ci-how-to-connect-to-the-docker-container-started-in-gitlab-ci-yml-scri

标签

Docker

docker-compose

gitlab-ci

docker-dind