From 9769ea1ba4aaa194f5df23138394558e4d501d85 Mon Sep 17 00:00:00 2001
From: Stephan Schnabel <stephan@schnabel.org>
Date: Tue, 24 Jun 2025 21:12:16 +0200
Subject: [PATCH] Add option to source env from file

---
 README.md     | 1 +
 entrypoint.sh | 9 +++++++++
 2 files changed, 10 insertions(+)

diff --git a/README.md b/README.md
index 56eea68..f042d9e 100644
--- a/README.md
+++ b/README.md
@@ -86,6 +86,7 @@ docker run --rm --user=$(id -u) --volume=$HOME:$HOME:ro --workdir=$PWD --env=PLU
 | `annotation`        | PLUGIN_ANNOTATION        | `none`           | Annotations (also known as labels) to add to image                                              |
 | `push`              | PLUGIN_PUSH              | `true`           | Push images if output names are set.                                                            |
 | `auth`              | PLUGIN_AUTH              | `none`           | Auth for private registries                                                                     |
+| `env-file`          | PLUGIN_ENV_FILE          | `none`           | Source environment values from given file                                                       |
 
 ## Alternatives
 
diff --git a/entrypoint.sh b/entrypoint.sh
index 21b3ea9..c13fbc3 100755
--- a/entrypoint.sh
+++ b/entrypoint.sh
@@ -5,6 +5,15 @@ set -eu;
 ## check input
 ##
 
+if [[ -n "${PLUGIN_ENV_FILE:-}" ]]; then
+	if [[ ! -f "PLUGIN_ENV_FILE" ]]; then
+		echo "Env file $PLUGIN_ENV_FILE not found."
+		exit 1
+	fi
+	# shellcheck source=/dev/null
+	source "$PLUGIN_ENV_FILE"
+fi
+
 BUILDCTL_CONTEXT=${PLUGIN_CONTEXT:-$(pwd)}
 BUILDCTL_DOCKERFILE=$(dirname "${PLUGIN_DOCKERFILE:-$BUILDCTL_CONTEXT/Dockerfile}")
 if [[ ! -f $BUILDCTL_DOCKERFILE/Dockerfile ]]; then