ci: Remove "publish" step (#2936)

This commit removes the publish step in GitHub actions, insteading
folding all functionality into the release build steps. This avoids
having a separately scheduled job after all the release build jobs which
ends up getting delayed for quite a long time given the current
scheduling algorithm.

This involves refactoring the tarball assembly scripts and refactoring the
github asset upload script too. Tarball assembly now manages everything
internally and does platform-specific bits where necessary. The upload
script is restructured to be run in parallel (in theory) and hopefully
catches various errors and tries to not stomp over everyone else's work.
The main trickiness here is handling `dev`, which is less critical for
correctness than than tags themselves.

As a small tweak build-wise the QEMU build for cross-compiled builders
is now cached unlike before where it was unconditionally built, shaving
a minute or two off build time.

.github/actions/github-release/Dockerfile

@@ -1,8 +0,0 @@
-FROM node:slim
-
-COPY . /action
-WORKDIR /action
-
-RUN npm install --production
-
-ENTRYPOINT ["node", "/action/main.js"]

.github/actions/github-release/action.yml

@@ -4,12 +4,9 @@ inputs:
   token:
     description: ''
     required: true
-  name:
-    description: ''
-    required: true
   files:
     description: ''
     required: true
 runs:
-  using: 'docker'
-  image: 'Dockerfile'
+  using: 'node12'
+  main: 'main.js'

.github/actions/github-release/main.js

@@ -11,12 +11,15 @@ function sleep(milliseconds) {
 async function runOnce() {
   // Load all our inputs and env vars. Note that `getInput` reads from `INPUT_*`
   const files = core.getInput('files');
-  const name = core.getInput('name');
   const token = core.getInput('token');
   const slug = process.env.GITHUB_REPOSITORY;
   const owner = slug.split('/')[0];
   const repo = slug.split('/')[1];
   const sha = process.env.GITHUB_SHA;
+  let name = 'dev';
+  if (process.env.GITHUB_REF.startsWith('refs/tags/v')) {
+    name = process.env.GITHUB_REF.substring(10);
+  }
 
   core.info(`files: ${files}`);
   core.info(`name: ${name}`);
@@ -24,53 +27,88 @@ async function runOnce() {
 
   const octokit = new github.GitHub(token);
 
-  // Delete the previous release since we can't overwrite one. This may happen
-  // due to retrying an upload or it may happen because we're doing the dev
-  // release.
-  const releases = await octokit.paginate("GET /repos/:owner/:repo/releases", { owner, repo });
-  for (const release of releases) {
-    if (release.tag_name !== name) {
-      continue;
+  // For the `dev` release we may need to update the tag to point to the new
+  // commit on this branch. All other names should already have tags associated
+  // with them.
+  if (name == 'dev') {
+    let tag = null;
+    try {
+      tag = await octokit.request("GET /repos/:owner/:repo/git/refs/tags/:name", { owner, repo, name });
+      core.info(`found existing tag`);
+      console.log("tag: ", JSON.stringify(tag.data, null, 2));
+    } catch (e) {
+      // ignore if this tag doesn't exist
+      core.info(`no existing tag found`);
+    }
+
+    if (tag === null || tag.data.object.sha !== sha) {
+      core.info(`updating existing tag or creating new one`);
+      // Delete the previous release for this tag, if any
+      try {
+        core.info(`fetching release for ${name}`);
+        const release = await octokit.repos.getReleaseByTag({ owner, repo, tag: name });
+        core.info(`deleting release ${release.data.id}`);
+        await octokit.repos.deleteRelease({ owner, repo, release_id: release.data.id });
+      } catch (e) {
+        // ignore, there may not have been a release
+        console.log("ERROR: ", JSON.stringify(e, null, 2));
+      }
+
+      try {
+        core.info(`updating dev tag`);
+        await octokit.git.updateRef({
+            owner,
+            repo,
+            ref: 'tags/dev',
+            sha,
+            force: true,
+        });
+      } catch (e) {
+        console.log("ERROR: ", JSON.stringify(e, null, 2));
+        core.info(`creating dev tag`);
+        try {
+          await octokit.git.createTag({
+            owner,
+            repo,
+            tag: 'dev',
+            message: 'dev release',
+            object: sha,
+            type: 'commit',
+          });
+        } catch (e) {
+          // we might race with others, so assume someone else has created the
+          // tag by this point.
+        }
+      }
+    } else {
+      core.info(`existing tag works`);
     }
-    const release_id = release.id;
-    core.info(`deleting release ${release_id}`);
-    await octokit.repos.deleteRelease({ owner, repo, release_id });
   }
 
-  // We also need to update the `dev` tag while we're at it on the `dev` branch.
-  if (name == 'dev') {
+  // Try to load the release for this tag, and if it doesn't exist then make a
+  // new one. We might race with other builders on creation, though, so if the
+  // creation fails try again to get the release by the tag.
+  let release = null;
+  try {
+    core.info(`fetching release`);
+    release = await octokit.repos.getReleaseByTag({ owner, repo, tag: name });
+  } catch (e) {
+    console.log("ERROR: ", JSON.stringify(e, null, 2));
+    core.info(`creating a release`);
     try {
-      core.info(`updating dev tag`);
-      await octokit.git.updateRef({
-          owner,
-          repo,
-          ref: 'tags/dev',
-          sha,
-          force: true,
-      });
-    } catch (e) {
-      console.log("ERROR: ", JSON.stringify(e, null, 2));
-      core.info(`creating dev tag`);
-      await octokit.git.createTag({
+      release = await octokit.repos.createRelease({
         owner,
         repo,
-        tag: 'dev',
-        message: 'dev release',
-        object: sha,
-        type: 'commit',
+        tag_name: name,
+        prerelease: name === 'dev',
       });
+    } catch(e) {
+      console.log("ERROR: ", JSON.stringify(e, null, 2));
+      core.info(`fetching one more time`);
+      release = await octokit.repos.getReleaseByTag({ owner, repo, tag: name });
     }
   }
-
-  // Creates an official GitHub release for this `tag`, and if this is `dev`
-  // then we know that from the previous block this should be a fresh release.
-  core.info(`creating a release`);
-  const release = await octokit.repos.createRelease({
-    owner,
-    repo,
-    tag_name: name,
-    prerelease: name === 'dev',
-  });
+  console.log("found release: ", JSON.stringify(release.data, null, 2));
 
   // Upload all the relevant assets for this release as just general blobs.
   for (const file of glob.sync(files)) {