testcontainers/testcontainers-java

Docker Compose support doesn't see local Docker images

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#239 opened on Oct 27, 2016

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Description

I have a project where I've attempted to do the following:

  1. Build an image of the project's application, locally (without pushing into a registry);
  2. Set up an integration test suite that runs after the image has been built;
  3. Have a test case in that suite that uses TestContainer's Compose support to launch a composition that uses the image from step 1.

This however doesn't work, because TestContainers runs Compose inside a container, and it evidently doesn't see the image that's locally built on step 1.

Another symptom of this same problem is that the Compose container, every time it runs, pulls public images afresh from Docker Hub even though they are locally cached on the Docker host.

Contributor guide

Tech stack
javadocker
Domain
testingbackenddevops
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
JavaDockerTestcontainers basics
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Investigate how Testcontainers launches Docker Compose (likely via a container). The issue suggests that the Compose container does not share the local Docker image cache. Look into the ComposeContainer.java class and how it mounts the Docker socket. Consider whether we need to mount additional volumes or use a specific Docker client configuration to share local images. Also check if there is a way to reference locally built images by specifying the image tag in the compose file. The maintainers may need to decide on the best approach (e.g., pre pulling images or using a shared volume).