Runtime configuration

Three environment variables let you adjust container behaviour without modifying aliases.

Table of contents

  1. DOCKER_DEVTOOLS_TTY
  2. DOCKER_DEVTOOLS_MAP_HOST_USER
  3. DOCKER_DEVTOOLS_EXTRA_ARGS
  4. --entrypoint <name> (alias definitions)

DOCKER_DEVTOOLS_TTY

Controls whether -it (interactive + TTY) is passed to docker run.

Value Behaviour
always (default) Always pass -it
auto Pass -it only when stdin and stdout are connected to a terminal
never Never pass -it (safe for scripts and CI) 
# Disable TTY for use in a CI pipeline or script
DOCKER_DEVTOOLS_TTY=never phpcs-generic src/

DOCKER_DEVTOOLS_MAP_HOST_USER

When set to a truthy value (true, 1, yes, on), adds --user $(id -u):$(id -g) so files written by the container are owned by the current host user instead of root.

DOCKER_DEVTOOLS_MAP_HOST_USER=true composer-docker install

Accepts: true, 1, yes, on (enable) or false, 0, no, off, empty (disable — default).

DOCKER_DEVTOOLS_EXTRA_ARGS

A space-separated list of extra flags appended to docker run before the image name. Useful for network, registry, or pull-policy overrides.

# Force a fresh pull and use the host network
DOCKER_DEVTOOLS_EXTRA_ARGS="--pull always --network host" stylelint-docker .

You can export these variables in your shell profile to apply them globally:

export DOCKER_DEVTOOLS_TTY=auto
export DOCKER_DEVTOOLS_MAP_HOST_USER=true

--entrypoint <name> (alias definitions)

Some multi-tool images (e.g. ImageMagick, libvips, WebP) bake in a default entrypoint that doesn’t match every binary the image ships. Alias authors can override it by passing --entrypoint <name> immediately after the image in a docker_alias call:

alias mogrify-docker="docker_alias /imgs dpokidov/imagemagick:latest --entrypoint mogrify"