pull base images for releasing

Author: tonglil

Makefile

@@ -14,3 +14,11 @@ push:
 	bin/push
 
 docker: build push
+
+pull:
+	docker pull tonglil/auth-gcloud:latest
+	docker pull tonglil/auth-gcloud:slim
+	docker pull tonglil/auth-gcloud:alpine
+
+version:
+	docker run -it --rm --entrypoint=bash tonglil/auth-gcloud:alpine gcloud version

README.md

@@ -33,6 +33,15 @@ pipeline:
     secret: [google_credentials]
 ```
 
+## Releasing
+
+Use the base image's `gcloud` version number as the tag:
+
+```
+make pull
+make version
+```
+
 ## Changelog
 
 See release notes: https://github.com/tonglil/auth-gke/releases

bin/build

@@ -4,4 +4,4 @@ cd "$(cd "$(dirname "$0")"; cd ..; pwd)"
 
 source bin/vars
 
-docker build -t "$OWNER/$NAME:$TAG" -f "$DOCKERFILE" .
+docker build --pull -t "$OWNER/$NAME:$TAG" -f "$DOCKERFILE" .