Adds script to help craft release notes

Signed-off-by: Paul Czarkowski <username.taken@gmail.com>

Makefile

@@ -181,6 +181,21 @@ checksum:
 clean:
 	@rm -rf $(BINDIR) ./_dist
 
+.PHONY: release-notes
+release-notes:
+		@if [ ! -d "./_dist" ]; then \
+			echo "please run 'make fetch-release' first" && \
+			exit 1; \
+		fi
+		@if [ -z "${PREVIOUS_RELEASE}" ]; then \
+			echo "please set PREVIOUS_RELEASE environment variable" \
+			&& exit 1; \
+		fi
+
+		@./scripts/release-notes.sh ${PREVIOUS_RELEASE} ${VERSION}
+
+
+
 .PHONY: info
 info:
 	 @echo "Version:           ${VERSION}"

scripts/release-notes.sh

@@ -0,0 +1,89 @@
+#!/bin/bash
+
+RELEASE=${RELEASE:-$2}
+PREVIOUS_RELEASE=${PREVIOUS_RELEASE:-$1}
+
+## Ensure Correct Usage
+if [[ -z "${PREVIOUS_RELEASE}" || -z "${RELEASE}" ]]; then
+  echo Usage:
+  echo ./scripts/release-notes.sh v3.0.0 v3.1.0
+  echo or
+  echo PREVIOUS_RELEASE=v3.0.0
+  echo RELEASE=v3.1.0
+  echo ./scripts/release-notes.sh
+  exit 1
+fi
+
+## validate git tags
+for tag in $RELEASE $PREVIOUS_RELEASE; do
+  OK=$(git tag -l ${tag} | wc -l)
+  if [[ "$OK" == "0" ]]; then
+    echo ${tag} is not a valid release version
+    exit 1
+  fi
+done
+
+## Check for hints that checksum files were downloaded
+## from `make fetch-dist`
+if [[ ! -e "./_dist/helm-${RELEASE}-darwin-amd64.tar.gz.sha256" ]]; then
+  echo "checksum file ./_dist/helm-${RELEASE}-darwin-amd64.tar.gz.sha256 not found in ./_dist/"
+  echo "Did you forget to run \`make fetch-dist\` first ?"
+  exit 1
+fi
+
+## Generate CHANGELOG from git log
+CHANGELOG=$(git log --no-merges --pretty=format:'- %s %H (%aN)' ${PREVIOUS_RELEASE}..${RELEASE})
+if [[ ! $? -eq 0 ]]; then
+  echo "Error creating changelog"
+  echo "try running \`git log --no-merges --pretty=format:'- %s %H (%aN)' ${PREVIOUS_RELEASE}..${RELEASE}\`"
+  exit 1
+fi
+
+## guess at MAJOR / MINOR / PATCH versions
+MAJOR=$(echo ${RELEASE} | sed 's/^v//' | cut -f1 -d.)
+MINOR=$(echo ${RELEASE} | sed 's/^v//' | cut -f2 -d.)
+PATCH=$(echo ${RELEASE} | sed 's/^v//' | cut -f3 -d.)
+
+## Print release notes to stdout
+cat <<EOF
+## ${RELEASE}
+
+Helm ${RELEASE} is a feature release. This release, we focused on <insert focal point>. Users are encouraged to upgrade for the best experience.
+
+The community keeps growing, and we'd love to see you there!
+
+- Join the discussion in [Kubernetes Slack](https://kubernetes.slack.com):
+  - `#helm-users` for questions and just to hang out
+  - `#helm-dev` for discussing PRs, code, and bugs
+- Hang out at the Public Developer Call: Thursday, 9:30 Pacific via [Zoom](https://zoom.us/j/696660622)
+- Test, debug, and contribute charts: [GitHub/helm/charts](https://github.com/helm/charts)
+
+## Notable Changes
+
+- Add list of
+- notable changes here
+
+## Installation and Upgrading
+
+Download Helm ${RELEASE}. The common platform binaries are here:
+
+- [MacOS amd64](https://get.helm.sh/helm-${RELEASE}-darwin-amd64.tar.gz) ([checksum](https://get.helm.sh/helm-${RELEASE}-darwin-amd64.tar.gz.sha256) / $(cat _dist/helm-${RELEASE}-darwin-amd64.tar.gz.sha256))
+- [Linux amd64](https://get.helm.sh/helm-${RELEASE}-linux-amd64.tar.gz) ([checksum](https://get.helm.sh/helm-${RELEASE}-linux-amd64.tar.gz.sha256) / $(cat _dist/helm-${RELEASE}-linux-amd64.tar.gz.sha256))
+- [Linux arm](https://get.helm.sh/helm-${RELEASE}-linux-arm.tar.gz) ([checksum](https://get.helm.sh/helm-${RELEASE}-linux-arm.tar.gz.sha256) / $(cat _dist/helm-${RELEASE}-linux-arm.tar.gz.sha256))
+- [Linux arm64](https://get.helm.sh/helm-${RELEASE}-linux-arm64.tar.gz) ([checksum](https://get.helm.sh/helm-${RELEASE}-linux-arm64.tar.gz.sha256) / $(cat _dist/helm-${RELEASE}-linux-arm64.tar.gz.sha256))
+- [Linux i386](https://get.helm.sh/helm-${RELEASE}-linux-386.tar.gz) ([checksum](https://get.helm.sh/helm-${RELEASE}-linux-386.tar.gz.sha256) / $(cat _dist/helm-${RELEASE}-linux-386.tar.gz.sha256))
+- [Linux ppc64le](https://get.helm.sh/helm-${RELEASE}-linux-ppc64le.tar.gz) ([checksum](https://get.helm.sh/helm-${RELEASE}-linux-ppc64le.tar.gz.sha256) / $(cat _dist/helm-${RELEASE}-linux-ppc64le.tar.gz.sha256))
+- [Linux s390x](https://get.helm.sh/helm-${RELEASE}-linux-s390x.tar.gz) ([checksum](https://get.helm.sh/helm-${RELEASE}-linux-s390x.tar.gz.sha256) / $(cat _dist/helm-${RELEASE}-darwin-amd64.tar.gz.sha256))
+- [Windows amd64](https://get.helm.sh/helm-${RELEASE}-windows-amd64.zip) ([checksum](https://get.helm.sh/helm-${RELEASE}-windows-amd64.zip.sha256) / $(cat _dist/helm-${RELEASE}-windows-amd64.zip.sha256))
+
+The [Quickstart Guide](https://docs.helm.sh/using_helm/#quickstart-guide) will get you going from there. For **upgrade instructions** or detailed installation notes, check the [install guide](https://docs.helm.sh/using_helm/#installing-helm). You can also use a [script to install](https://raw.githubusercontent.com/helm/helm/master/scripts/get-helm-3) on any system with \`bash\`.
+
+## What's Next
+
+- ${MAJOR}.${MINOR}.$(expr ${PATCH} + 1) will contain only bug fixes.
+- ${MAJOR}.$(expr ${MINOR} + 1).${PATCH} is the next feature release. This release will focus on ...
+
+## Changelog
+
+${CHANGELOG}
+EOF