ci: add steps to create releases on vA.B.C tag events

the steps create a tar.gz with all files found in dist/ dir.
additionally, an ad-hoc build.txt file is created with build info.
the bot then creates a release and uploads the tar.gz as an artifact.

the idea is that all nostr web app instances are notified about the new
release, download the tar.gz and update their local copy. this is not
yet implemented.

.woodpecker.yml

@@ -4,3 +4,23 @@ pipeline:
     commands:
       - npm ci
       - npm run build
+  prepare_release:
+    when:
+      event: tag
+      branch: master
+      tag: v*
+    image: node:18-slim
+    commands:
+      - tools/ci-make-release-targz.sh
+  create_release:
+    when:
+      event: tag
+      branch: master
+      tag: v*
+    image: plugins/gitea-release
+    settings:
+      api_key:
+        from_secret: releaser_auth_token
+      base_url: https://git.qcode.ch
+      files: nostrweb.tar.gz
+      note: "automated release by ${CI_SYSTEM_HOST} \nbuild id: ${CI_BUILD_NUMBER}"

README.md

@@ -27,3 +27,18 @@ execute
 
 the build is done using [esbuild](https://esbuild.github.io/), with a config in
 [esbuildconf.js](esbuildconf.js). the result is placed in `dist` directory.
+
+## release
+
+1. make sure `version` field in [package.json](package.json) as seen by remote
+git on **master** branch matches the tag created in the next step.
+2. tag a commit on **master** branch with a `git tag v<vesion>`.
+3. push the tag to the remote: `git push --tags`.
+
+the CI then receives a git tag event, executes `npm run build`, creates
+a tar.gz with all the files found in `dist` directory and uploads it as a new
+release artifact. the release is named after the tag name.
+
+the idea is that nostr web instances are then notified about a new release,
+download the tar.gz archive and update their local copies.
+this is not yet implemented.

tools/ci-make-release-targz.sh

@@ -0,0 +1,16 @@
+#!/bin/sh
+set -e
+
+# assuming the script is run from the repo root dir
+cd dist
+
+# create build metadata
+truncate -s0 build.txt
+echo "remote: $CI_REPO_REMOTE" >> build.txt
+echo "commit: $CI_COMMIT_SHA" >> build.txt
+echo "tag: $CI_COMMIT_TAG" >> build.txt
+echo "build id: $CI_BUILD_NUMBER" >> build.txt
+cat build.txt
+
+# make the release archive in the repo root dir
+tar -czvf ../nostrweb.tar.gz *