Hook Context Env

Expose additional TG_CTX_* environment variables to hook scripts.

hook-context-env - What it does

When enabled, Terragrunt sets three additional environment variables on the process running every before_hook, after_hook, and error_hook:

• TG_CTX_HOOK_TYPE — before_hook, after_hook, or error_hook, depending on which lifecycle phase is executing the hook.
• TG_CTX_SOURCE — the resolved terraform source URL for the current unit, matching the precedence Terragrunt uses for the actual download: the --source CLI override if set, otherwise the evaluated terraform.source (with --source-map applied), otherwise ..
• TG_CTX_TERRAGRUNT_DIR — the directory containing the current Terragrunt config (equivalent to get_terragrunt_dir()).

These variables make it easier for hook scripts to branch on lifecycle phase, to know whether the unit pulls remote source, and to locate the config directory without having to thread that information through hook arguments.

terragrunt run --all --experiment hook-context-env -- apply

Example hook script:

#!/usr/bin/env bash

case "$TG_CTX_HOOK_TYPE" in
  before_hook) echo "preparing $TG_CTX_TERRAGRUNT_DIR" ;;
  after_hook)  echo "cleaning up $TG_CTX_TERRAGRUNT_DIR" ;;
  error_hook)  echo "failure in $TG_CTX_TERRAGRUNT_DIR" ;;
esac

if [ "$TG_CTX_SOURCE" != "." ]; then
  echo "unit uses source: $TG_CTX_SOURCE"
fi

hook-context-env - How to provide feedback

Provide your feedback in the hook-context-env GitHub Discussion.

hook-context-env - Criteria for stabilization

To transition the hook-context-env feature to a stable release, the following must be addressed:

• Confirm the three new variables cover the most common hook scripting needs.
• Confirm the chosen variable names and values (before_hook/after_hook/error_hook) match user expectations.
• Positive feedback from users relying on the variables in production hook scripts.