build: Add changelog generation plumbing

.github/workflows/main.yaml

@@ -40,7 +40,10 @@ jobs:
           scripts/alpine-setup.sh
           GOOS=darwin GOARCH=amd64 make all
           GOOS=linux GOARCH=amd64 make all
+          make changelog
         shell: sh
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       - name: Archive release artifacts
         uses: actions/upload-artifact@v1
         with:
@@ -69,6 +72,7 @@ jobs:
           release_name: Release ${{ steps.get_tag.outputs.git_tag }}
           draft: true
           prerelease: false
+          body_path: ./release-artifacts/changelog.md
       - name: Upload Release Asset - Mac
         id: upload-release-asset-mac
         uses: actions/upload-release-asset@v1

Makefile

@@ -34,6 +34,7 @@ RELEASE_DIR ?= release-artifacts
 PACKED_DIR ?= $(BIN_DIR)/packed
 CMDS ?= $(shell ls $(CMD_DIR))
 BINS ?= $(addsuffix -$(GOOS)-$(GOARCH),$(addprefix $(BIN_DIR)/,$(CMDS)))
+CHANGELOG ?= changelog.md
 
 BIN_ARCH ?= $(GOOS)-$(GOARCH)
 RELEASE_SUFFIX ?= $(GIT_REF)-$(BIN_ARCH).tar.gz
@@ -118,3 +119,8 @@ clean:
 	rm -rf $(GENERATE_DIR)
 	rm -rf $(BIN_DIR)
 .PHONY: clean
+
+## Generate Changelog based on PRs
+changelog:
+	OUTPUT_FILE=$(RELEASE_DIR)/$(CHANGELOG) ./scripts/github-changelog.sh
+.PHONY: changelog

README.md

@@ -178,6 +178,31 @@ Use imperative, present tense (Add, not ~Added~), capitalize first letter of
 summary, no dot at the and. The body and footer are optional. Relevant GitHub
 issues should be referenced in the footer in the form `Fixes #123, fixes #456`.
 
+### Changelog
+
+Changelog is generated automatically based on merged PRs using
+[changelog-gen][chlg-gen]. Template can be found in `scripts/changelog.tmpl`.
+
+PRs are categorized based on their labels, into following sections:
+- Announcements - `announcement` label
+- Breaking Changes - `breaking-change` label
+- Features - `feature` label
+- Changes - `change` label
+- Fixes - `fix` label
+- Internal/Other - everything else
+
+PR can be excluded from changelog with `no-release-note` label. PR title is
+used by default, however, the copy can be customized by including following
+block in the PR body:
+
+~~~
+```release-note
+This is an example release note!
+```
+~~~
+
+[chlg-gen]: https://github.com/paultyng/changelog-gen
+
 ## Issues and Contributions
 
 Please open any issues and/or PRs against github.com/doitintl/kube-no-trouble repository.

scripts/alpine-setup.sh

@@ -8,7 +8,9 @@ UPX_VERSION="3.96"
 OPA_VERSION="0.22.0"
 
 apk add --update --no-cache \
+	curl \
 	git \
+	jq \
 	make \
 	tar
 
@@ -20,3 +22,4 @@ wget -q -O "/usr/local/bin/opa" "https://github.com/open-policy-agent/opa/releas
 chmod +x "/usr/local/bin/opa"
 
 go get github.com/rakyll/statik
+go get github.com/paultyng/changelog-gen

scripts/changelog.tmpl

@@ -0,0 +1,68 @@
+{{- $announcements := newStringList -}}
+{{- $breaking := newStringList -}}
+{{- $features := newStringList -}}
+{{- $changes := newStringList -}}
+{{- $fixes := newStringList -}}
+{{- $other := newStringList -}}
+
+{{- range . -}}
+  {{if has "announcement" .Labels -}}
+	{{$features = append $announcements (renderReleaseNote .) -}}
+  {{else if .BreakingChange -}}
+	{{$breaking = append $breaking (renderReleaseNote .) -}}
+  {{else if has "feature" .Labels -}}
+	{{$features = append $features (renderReleaseNote .) -}}
+  {{else if has "change" .Labels -}}
+	{{$fixes = append $changes (renderReleaseNote .) -}}
+  {{else if has "fix" .Labels -}}
+	{{$fixes = append $fixes (renderReleaseNote .) -}}
+  {{else -}}
+	{{$other = append $other (renderReleaseNote .) -}}
+  {{end -}}
+{{- end -}}
+
+{{- if gt (len $announcements) 0 -}}
+{{range $announcements | sortAlpha -}}
+{{. }}
+{{end -}}
+{{- end -}}
+
+{{- if gt (len $breaking) 0 -}}
+**Breaking Changes**:
+
+{{range $breaking | sortAlpha -}}
+* {{. }}
+{{end -}}
+{{- end -}}
+
+{{- if gt (len $features) 0}}
+**Features**:
+
+{{range $features | sortAlpha -}}
+* {{. }}
+{{end -}}
+{{- end -}}
+
+{{- if gt (len $changes) 0}}
+**Changes**:
+
+{{range $changes | sortAlpha -}}
+* {{. }}
+{{end -}}
+{{- end -}}
+
+{{- if gt (len $fixes) 0}}
+**Fixes**:
+
+{{range $fixes | sortAlpha -}}
+* {{. }}
+{{end -}}
+{{- end -}}
+
+{{- if gt (len $other) 0}}
+**Internal/Other**:
+
+{{range $other | sortAlpha -}}
+* {{. }}
+{{end -}}
+{{- end -}}

scripts/github-changelog.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env sh
+# Set strict error checking
+set -emou pipefail
+
+GH_ORG="doitintl"
+GH_REPO="kube-no-trouble"
+CHANGELOG_TEMPLATE="./scripts/changelog.tmpl"
+OUTPUT_FILE="${OUTPUT_FILE:="./changelog.md"}"
+
+RELEASE_SHA="$(curl --silent "https://api.github.com/repos/${GH_ORG}/${GH_REPO}/releases/latest" \
+	| jq -r '.target_commitish')"
+MASTER_SHA="$(git rev-parse origin/master)"
+
+echo "- Generating changelog (${OUTPUT_FILE})"
+
+changelog-gen -changelog "${CHANGELOG_TEMPLATE}" \
+	-owner "${GH_ORG}" -repo "${GH_REPO}" \
+	"${RELEASE_SHA}" "${MASTER_SHA}" | tee "${OUTPUT_FILE}"