Documentation
Extensibility
Container

Container

Extension can run actions in a Docker container when container is specified on an extension block:

extension @terraform {
    container = "hashicorp/terraform:1.8.4"
    platform = "linux/arm64"
    variables = [ "ARM_*"
                  "MYSECRET" ]
}

Argument Reference

The following arguments are supported:

  • container - (Optional) The Docker image to use. Default is nothing.
  • platform - (Optional) The platform for the Docker image. Default is nothing (i.e.: current host architecture).
  • variables - (Optional) List of variables to pass to Docker instance. Supports wildcards. Default is [].

All actions for this extension will run in the configured container - hence providing both isolation and avoiding toolchains discrepancies.

⚠️
On macOS, it’s recommended to use OrbStack as it’s much faster than Docker implementation.

Technical implementation

All actions are run using following docker configuration:

  • Entrypoint and arguments are overriden by action (--entrypoint)
  • Command runs as PID 1 (--init)
  • Container is configured for 1Gb of shared memory (--shm-size=1gb)
  • Container is removed after execution (--rm)
  • Container uses provided platform - use default if none
  • Docker host socket is exposed to container to allow Docker in Docker (-v /var/run/docker.sock)
  • Container USER account is identified and used to map host homedir to USER homedir (-v)
  • Container /tmp is redirected and shared across instances (v)
  • Container workdir is the current project rootdir (-w)
  • Network is set to host (--net=host)
  • IPC is set to host (--ipc=host)
  • PID is set to host (--pid=host)
  • Environment variables can be passed from host to container (-e) - see variables property of extensions.
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