update downloadTool to handle errors from response stream and retry (#369)

packages/tool-cache/src/retry-helper.ts

@@ -0,0 +1,55 @@
+import * as core from '@actions/core'
+
+/**
+ * Internal class for retries
+ */
+export class RetryHelper {
+  private maxAttempts: number
+  private minSeconds: number
+  private maxSeconds: number
+
+  constructor(maxAttempts: number, minSeconds: number, maxSeconds: number) {
+    if (maxAttempts < 1) {
+      throw new Error('max attempts should be greater than or equal to 1')
+    }
+
+    this.maxAttempts = maxAttempts
+    this.minSeconds = Math.floor(minSeconds)
+    this.maxSeconds = Math.floor(maxSeconds)
+    if (this.minSeconds > this.maxSeconds) {
+      throw new Error('min seconds should be less than or equal to max seconds')
+    }
+  }
+
+  async execute<T>(action: () => Promise<T>): Promise<T> {
+    let attempt = 1
+    while (attempt < this.maxAttempts) {
+      // Try
+      try {
+        return await action()
+      } catch (err) {
+        core.info(err.message)
+      }
+
+      // Sleep
+      const seconds = this.getSleepAmount()
+      core.info(`Waiting ${seconds} seconds before trying again`)
+      await this.sleep(seconds)
+      attempt++
+    }
+
+    // Last attempt
+    return await action()
+  }
+
+  private getSleepAmount(): number {
+    return (
+      Math.floor(Math.random() * (this.maxSeconds - this.minSeconds + 1)) +
+      this.minSeconds
+    )
+  }
+
+  private async sleep(seconds: number): Promise<void> {
+    return new Promise(resolve => setTimeout(resolve, seconds * 1000))
+  }
+}