Improve container image startup

.docker/copybara

@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+
+# Handle environment variables for backwards compatibility
+if [ -n "$COPYBARA_SUBCOMMAND" ] || [ -n "$COPYBARA_CONFIG" ] || [ -n "$COPYBARA_WORKFLOW" ] || [ -n "$COPYBARA_SOURCEREF" ]; then
+  echo "Detected \$COPYBARA_* environment variables, overwriting shell args"
+  ARGS=()
+  if [ -n "$COPYBARA_SUBCOMMAND" ]; then
+    ARGS+=("$COPYBARA_SUBCOMMAND")
+  else
+    ARGS+=("migrate")
+  fi
+  if [ -n "$COPYBARA_CONFIG" ]; then
+    ARGS+=("$COPYBARA_CONFIG")
+  else
+    ARGS+=("copy.bara.sky")
+  fi
+  if [ -n "$COPYBARA_WORKFLOW" ]; then
+    ARGS+=("$COPYBARA_WORKFLOW")
+  else
+    ARGS+=("default")
+  fi
+  if [ -n "$COPYBARA_SOURCEREF" ]; then
+    ARGS+=("$COPYBARA_SOURCEREF")
+  fi
+  echo "Setting arguments to: \"${ARGS[@]}\""
+  set -- "${ARGS[@]}"
+fi
+
+exec java -jar /opt/copybara/copybara_deploy.jar "$@"

Dockerfile

@@ -26,11 +26,8 @@ RUN apt-get update && apt-get install -y \
     && rm -rf /var/lib/apt/lists/*
 COPY --from=build /home/ubuntu/bazel-bin/java/com/google/copybara/copybara_deploy.jar /opt/copybara/
 COPY --from=buildtools /go/bin/buildozer /go/bin/buildifier /usr/bin/
-ENV COPYBARA_SUBCOMMAND="migrate" \
-    COPYBARA_CONFIG="copy.bara.sky" \
-    COPYBARA_WORKFLOW="default" \
-    COPYBARA_SOURCEREF="" \
-    COPYBARA_OPTIONS=""
-COPY .docker/entrypoint.sh /usr/local/bin/copybara
-RUN chmod +x /usr/local/bin/copybara
+# NOTE NullPointerException when using directly ENTRYPOINT["java","-jar","/opt/copybara/copybara_deploy.jar"]
+COPY .docker/copybara /usr/local/bin/copybara
+ENTRYPOINT ["/usr/local/bin/copybara"]
+CMD ["migrate", "copy.bara.sky"]
 WORKDIR /usr/src/app

README.md

@@ -167,27 +167,15 @@ Once this has finished building, you can run the image like so from the root of
 the code you are trying to use Copybara on:
 
 ```sh
-docker run -it -v "$(pwd)":/usr/src/app copybara copybara
+docker run -it -v "$(pwd)":/usr/src/app copybara
 ```
 
-A few environment variables exist to allow you to change how you run copybara:
-* `COPYBARA_CONFIG=copy.bara.sky`
-  * allows you to specify a path to a config file, defaults to root `copy.bara.sky`
-* `COPYBARA_SUBCOMMAND=migrate`
-  * allows you to change the command run, defaults to `migrate`
-* `COPYBARA_OPTIONS=''`
-  * allows you to specify options for copybara, defaults to none
-* `COPYBARA_WORKFLOW=default`
-  * allows you to specify the workflow to run, defaults to `default`
-* `COPYBARA_SOURCEREF=''`
-  * allows you to specify the sourceref, defaults to none
-
 ```sh
 docker run \
     -e COPYBARA_CONFIG='other.config.sky' \
     -e COPYBARA_SUBCOMMAND='validate' \
     -v "$(pwd)":/usr/src/app \
-    -it copybara copybara
+    -it copybara
 ```
 
 #### Git Config and Credentials
@@ -200,7 +188,7 @@ docker run \
     -v ~/.ssh:/root/.ssh \
     -v ~/.gitconfig:/root/.gitconfig \
     -v "$(pwd)":/usr/src/app \
-    -it copybara copybara
+    -it copybara
 ```
 
 ## Documentation