getViaCIArtifacts: add some resilience

Due to the fact that GitHub Release assets cannot be overwritten
atomically, there is an off-chance that the asset we're looking for is
not actually there.

In those rare circumstances when we try to download such an asset while
it has been deleted so that a new version can be uploaded, just wait a
little and try again.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

src/ci_artifacts.ts

@@ -4,6 +4,12 @@ import {getArtifactMetadata} from './git'
 import {spawn} from 'child_process'
 import * as fs from 'fs'
 
+async function sleep(milliseconds: number): Promise<void> {
+  return new Promise<void>((resolve, _reject) => {
+    setTimeout(resolve, milliseconds)
+  })
+}
+
 export async function getViaCIArtifacts(
   architecture: string,
   githubToken?: string
@@ -21,35 +27,51 @@ export async function getViaCIArtifacts(
 
   const octokit = githubToken ? new Octokit({auth: githubToken}) : new Octokit()
 
-  const ciArtifactsResponse = await octokit.repos.getReleaseByTag({
-    owner,
-    repo,
-    tag: 'ci-artifacts'
-  })
+  const {
+    name,
+    updated_at: updatedAt,
+    browser_download_url: url
+  } = await (async () => {
+    let error: Error | undefined
+    for (const seconds of [0, 5, 10, 15, 20, 40]) {
+      if (seconds) await sleep(seconds)
 
-  if (ciArtifactsResponse.status !== 200) {
-    throw new Error(
-      `Failed to get ci-artifacts release from the ${owner}/${repo} repo: ${ciArtifactsResponse.status}`
-    )
-  }
+      const ciArtifactsResponse = await octokit.repos.getReleaseByTag({
+        owner,
+        repo,
+        tag: 'ci-artifacts'
+      })
 
-  core.info(`Found ci-artifacts release: ${ciArtifactsResponse.data.html_url}`)
-  const tarGzArtifact = ciArtifactsResponse.data.assets.find(asset =>
-    asset.name.endsWith('.tar.gz')
-  )
+      if (ciArtifactsResponse.status !== 200) {
+        error = new Error(
+          `Failed to get ci-artifacts release from the ${owner}/${repo} repo: ${ciArtifactsResponse.status}`
+        )
+        continue
+      }
 
-  if (!tarGzArtifact) {
-    throw new Error(
-      `Failed to find a .tar.gz artifact in the ci-artifacts release of the ${owner}/${repo} repo`
-    )
-  }
+      core.info(
+        `Found ci-artifacts release: ${ciArtifactsResponse.data.html_url}`
+      )
+      const tarGzArtifact = ciArtifactsResponse.data.assets.find(asset =>
+        asset.name.endsWith('.tar.gz')
+      )
 
-  const url = tarGzArtifact.browser_download_url
-  core.info(`Found ${tarGzArtifact.name} at ${url}`)
+      if (!tarGzArtifact) {
+        error = new Error(
+          `Failed to find a .tar.gz artifact in the ci-artifacts release of the ${owner}/${repo} repo`
+        )
+        continue
+      }
+
+      return tarGzArtifact
+    }
+    throw error
+  })()
+  core.info(`Found ${name} at ${url}`)
 
   return {
     artifactName,
-    id: `ci-artifacts-${tarGzArtifact.updated_at}`,
+    id: `ci-artifacts-${updatedAt}`,
     download: async (
       outputDirectory: string,
       verbose: number | boolean = false