feat(release.yml): Add a (3 jobs)-based GHA using release-please

* Use var OPAM_RELEASE (GitHub PAC)

* Use "expect" to workaround the lack of this feature:
  ocaml-opam/opam-publish#132

Co-Authored-By: Yann Régis-Gianas <[email protected]>
Co-Authored-By: Erik Martin-Dorel <[email protected]>

.github/workflows/release.yml

@@ -0,0 +1,119 @@
+name: Release
+# Credits: workflow inspired from
+# https://github.com/grain-lang/binaryen.ml/blob/master/.github/workflows/release.yml
+# then slightly adapted, using:
+# - https://github.com/googleapis/release-please#readme
+# - https://github.com/google-github-actions/release-please-action/blob/main/action.yml
+# - https://docs.github.com/en/actions/learn-github-actions/events-that-trigger-workflows#workflow_run
+# - https://docs.github.com/en/actions/advanced-guides/storing-workflow-data-as-artifacts
+# - https://github.com/dawidd6/action-download-artifact#readme
+# - https://hub.github.com/hub-release.1.html
+on:
+  workflow_run:
+    workflows: ["Generate static binaries"]
+    branches: ["master"]
+    types: ["completed"]
+  # TODO: dispatch?
+
+jobs:
+  release-please:
+    name: Create Release
+    runs-on: ubuntu-latest
+    if: ${{ github.event.workflow_run.conclusion == 'success' }}
+    outputs:
+      release_created: ${{ steps.release.outputs.release_created }}
+      upload_url: ${{ steps.release.outputs.upload_url }}
+      tag_name: ${{ steps.release.outputs.tag_name }}
+      body: ${{ steps.release.outputs.body }}
+    steps:
+      - uses: GoogleCloudPlatform/release-please-action@v2
+        id: release
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          release-type: ocaml
+          package-name: learn-ocaml
+          bump-minor-pre-major: true
+
+  add-binaries:
+    needs: [release-please]
+    if: ${{ needs.release-please.outputs.release_created }}
+    name: Add archive and binaries to release
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out the repo
+        # Mandatory step (otherwise, hub raises "fatal: Not a git repository")
+        uses: actions/checkout@v2
+      - name: Download workflow artifacts
+        # cf. https://github.com/actions/download-artifact/issues/3
+        uses: dawidd6/action-download-artifact@v2
+        with:
+          workflow: static-builds.yml
+          workflow_conclusion: success
+          commit: ${{ github.sha }}
+          path: artifacts
+      - name: Unpack workflow artifacts
+        run: |
+          cd artifacts
+          mkdir -v target
+          dist=(linux darwin)
+          artifact() { printf "learn-ocaml-%s-x86_64.tar.gz" "$d"; }
+          for d in "${dist[@]}"; do
+            mkdir -v -- "$d"
+            ( cd "$d" && tar xvzf "../$(artifact "$d")/$(artifact "$d")" )
+            bin=(./learn-ocaml-client ./learn-ocaml-server ./learn-ocaml)
+            for b in "${bin[@]}"; do
+              mv -v -- "$d/$b" "target/$b-$d-x86_64"
+            done
+          done
+      - name: Add binaries to release
+        run:
+          hub release edit $(find artifacts/target -type f -printf "-a %p ") -m "" "${{ needs.release-please.outputs.tag_name }}"
+
+  opam-release:
+    needs: [release-please]
+    if: ${{ needs.release-please.outputs.release_created }}
+    name: Publish to opam registry
+    env:
+      # Can be changed for debugging
+      source_repo: "ocaml-sf/learn-ocaml"
+      opam_repo: "ocaml/opam-repository"
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out the repo
+        uses: actions/checkout@v2
+      - name: Setup bot user
+        run: |
+          git config --global user.email "[email protected]"
+          git config --global user.name "Learn-OCaml Bot"
+      # Some hacks to make sure opam doesn't pull the repo in a way we can't deal with
+      - name: Setup opam repository
+        run: |
+          mkdir -v -p ~/.opam/plugins/opam-publish/repos/
+          git clone git://github.com/$opam_repo ~/.opam/plugins/opam-publish/repos/${opam_repo/\//%}
+          cd ~/.opam/plugins/opam-publish/repos/${opam_repo/\//%}
+          git remote add user https://${{ secrets.OPAM_RELEASE }}@github.com/proofbot/opam-repository
+      # Set up our token because opam doesn't support env var tokens
+      - name: Setup token
+        run: |
+          mkdir -p  ~/.opam/plugins/opam-publish/
+          echo -n ${{ secrets.OPAM_RELEASE }} > ~/.opam/plugins/opam-publish/proofbot.token
+      - name: Generate CHANGES file
+        env:
+          CHANGES: ${{ needs.release-please.outputs.body }}
+        run: |
+          printf "%s" "$CHANGES" > CHANGES.md
+      # TODO: Docker-based caching
+      - name: Setup OCaml
+        uses: avsm/setup-ocaml@v1
+        with:
+          ocaml-version: 4.12.0
+      - name: Install opam-publish
+        run: |
+          opam install -y -j 2 opam-publish
+      - name: Install expect
+        run: |
+          sudo apt-get update -y -q
+          sudo DEBIAN_FRONTEND=noninteractive apt-get install -y -q --no-install-recommends expect
+      - name: Publish to opam
+        run: |
+          ./scripts/opam-publish.exp "${{ needs.release-please.outputs.tag_name }}" "$opam_repo" "$source_repo"

scripts/opam-publish.exp

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+#!/usr/bin/expect -f
+
+set tag_name [lindex $argv 0]
+set opam_repo [lindex $argv 1]
+set source_repo [lindex $argv 2]
+
+# This Expect script was generated by autoexpect on Tue Oct  5 17:03:15 2021
+# then modified by Erik Martin-Dorel
+# Expect and autoexpect were both written by Don Libes, NIST.
+#
+# Note that autoexpect does not guarantee a working script.  It
+# necessarily has to guess about certain things.  Two reasons a script
+# might fail are:
+#
+# 1) timing - A surprising number of programs (rn, ksh, zsh, telnet,
+# etc.) and devices discard or ignore keystrokes that arrive "too
+# quickly" after prompts.  If you find your new script hanging up at
+# one spot, try adding a short sleep just before the previous send.
+# Setting "force_conservative" to 1 (see below) makes Expect do this
+# automatically - pausing briefly before sending each character.  This
+# pacifies every program I know of.  The -c flag makes the script do
+# this in the first place.  The -C flag allows you to define a
+# character to toggle this mode off and on.
+
+set force_conservative 0  ;# set to 1 to force conservative mode even if
+			  ;# script wasn't run conservatively originally
+if {$force_conservative} {
+	set send_slow {1 .1}
+	proc send {ignore arg} {
+		sleep .1
+		exp_send -s -- $arg
+	}
+}
+
+#
+# 2) differing output - Some programs produce different output each time
+# they run.  The "date" command is an obvious example.  Another is
+# ftp, if it produces throughput statistics at the end of a file
+# transfer.  If this causes a problem, delete these patterns or replace
+# them with wildcards.  An alternative is to use the -p flag (for
+# "prompt") which makes Expect only look for the last line of output
+# (i.e., the prompt).  The -P flag allows you to define a character to
+# toggle this mode off and on.
+#
+# Read the man page for more info.
+#
+# -Don
+
+
+set timeout -1
+spawn bash -c {export GIT_PAGER=cat && opam publish --no-browser --msg-file=CHANGES.md --tag "$1" --repo="$2" "$3"} bash "$tag_name" "$opam_repo" "$source_repo"
+match_max 100000
+expect -exact "Please confirm the above data. Continue ?  \[Y/n\] "
+send -- "y"
+expect -exact "File a pull-request for this patch ? \[Y/n\] "
+send -- "y"
+expect eof