github-action: create git release/tag (#144)

.github/workflows/create-tag.yml

@@ -0,0 +1,30 @@
+---
+# Creates a new GitHub release if the version in go.mod changed in the main branch and
+# if the tag does not exist yet.
+name: create-tag
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - go.mod
+
+permissions:
+  contents: read
+
+jobs:
+  tag:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        fetch-depth: 0 # also fetch tags
+
+    - uses: actions/setup-go@v5
+      with:
+        go-version-file: go.mod
+
+    - run: make create-release
+      env:
+        GH_TOKEN: ${{ secrets.CREATE_TAG_TOKEN }}

Makefile

@@ -2,6 +2,7 @@ PORT ?= 8000
 IMAGE ?= opbeans/opbeans-go
 VERSION ?= latest
 LTS_ALPINE ?= 12-alpine
+AGENT_VERSION=$(shell go list -f '{{.Version}}' -m go.elastic.co/apm/v2)
 
 .PHONY: help
 .DEFAULT_GOAL := help
@@ -35,3 +36,11 @@ publish: build ## Publish docker image
 clean: ## Clean autogenerated files/folders
 	@rm -rf bats
 	@rm -rf target
+
+create-release: ## Create github release given the APM Agent version if no tag release
+	@if [ -z "$(shell git tag -l $(AGENT_VERSION))" ]; then \
+		echo "creating tag $(AGENT_VERSION)"; \
+		gh release create "$(AGENT_VERSION)" --title="$(AGENT_VERSION)" --generate-notes; \
+	else \
+		echo "git tag $(AGENT_VERSION) already exists"; \
+	fi