Merge pull request #23 from tikurahul/main

Bring back retries when downloading blobs from the Storage cache.

Author: tikurahul

README.md

@@ -8,7 +8,7 @@ In your `settings.gradle.kts` file add the following
 
 ```kotlin
 plugins {
-    id("androidx.build.gradle.gcpbuildcache") version "1.0.0-alpha04"
+    id("androidx.build.gradle.gcpbuildcache") version "1.0.0-alpha05"
 }
 
 import androidx.build.gradle.gcpbuildcache.GcpBuildCache
@@ -36,7 +36,7 @@ If you are using Groovy, then you should do the following:
 
 ```groovy
 plugins {
-    id("androidx.build.gradle.gcpbuildcache") version "1.0.0-alpha04"
+    id("androidx.build.gradle.gcpbuildcache") version "1.0.0-alpha05"
 }
 
 import androidx.build.gradle.gcpbuildcache.GcpBuildCache

RELEASE-NOTES.md

@@ -1,5 +1,12 @@
 # Release notes for GCP backed Gradle Remote Cache
 
+## 1.0.0-alpha05
+
+- Downloads `Blob`s to an intermediate `Buffer` or a `File` depending on the size of the blob.
+- The underlying `FileHandleInputStream` gets cleaned up automatically after the `InputStream` is closed.
+- This way we can avoid flakes from the build cache, that is caused by intermittent `StorageException`s 
+- Retry on fetches given they are being fetched to an intermediate location.
+
 ## 1.0.0-alpha04
 
 - Handles exceptions when fetching `BlobInfo`s and `ReadChannel`s from the storage service.

gcpbuildcache/build.gradle.kts

@@ -54,7 +54,7 @@ gradlePlugin {
 }
 
 group = "androidx.build.gradle.gcpbuildcache"
-version = "1.0.0-alpha04"
+version = "1.0.0-alpha05"
 
 testing {
     suites {

gcpbuildcache/src/main/kotlin/androidx/build/gradle/gcpbuildcache/FileHandleInputStream.kt

@@ -0,0 +1,59 @@
+/*
+ * Copyright 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package androidx.build.gradle.gcpbuildcache
+
+import java.io.File
+import java.io.InputStream
+import java.nio.file.Files
+import java.nio.file.Path
+
+/**
+ * An input stream that keeps track of the file handles, so they can be cleaned up when the
+ * [FileHandleInputStream] is closed.
+ */
+internal class FileHandleInputStream(private val file: File) : InputStream() {
+    private val inputStream by lazy {
+        file.inputStream()
+    }
+
+    override fun read(): Int {
+        return inputStream.read()
+    }
+
+    override fun close() {
+        super.close()
+        try {
+            inputStream.close()
+        } finally {
+            check(file.delete()) {
+                "Unable to delete $file"
+            }
+        }
+    }
+
+    companion object {
+        fun Path.handleInputStream(): InputStream {
+            return FileHandleInputStream(this.toFile())
+        }
+
+        fun create(): Path {
+            val timestamp = System.nanoTime()
+            return Files.createTempFile("gradleCache", "$timestamp")
+        }
+    }
+}

gcpbuildcache/src/main/kotlin/androidx/build/gradle/gcpbuildcache/GcpStorageService.kt

@@ -17,15 +17,14 @@
 
 package androidx.build.gradle.gcpbuildcache
 
+import androidx.build.gradle.gcpbuildcache.FileHandleInputStream.Companion.handleInputStream
 import com.google.api.gax.retrying.RetrySettings
 import com.google.auth.oauth2.GoogleCredentials
-import com.google.cloud.ReadChannel
 import com.google.cloud.http.HttpTransportOptions
 import com.google.cloud.storage.*
 import org.gradle.api.GradleException
 import org.gradle.api.logging.Logging
 import java.io.InputStream
-import java.nio.channels.Channels
 
 /**
  * An implementation of the [StorageService] that is backed by Google Cloud Storage.
@@ -36,6 +35,7 @@ internal class GcpStorageService(
     gcpCredentials: GcpCredentials,
     override val isPush: Boolean,
     override val isEnabled: Boolean,
+    private val sizeThreshold: Long = BLOB_SIZE_THRESHOLD
 ) : StorageService {
 
     private val storageOptions by lazy { storageOptions(projectId, gcpCredentials, isPush) }
@@ -48,8 +48,7 @@ internal class GcpStorageService(
 
         val blobId = BlobId.of(bucketName, cacheKey)
         logger.info("Loading $cacheKey from ${blobId.name}")
-        val readChannel = load(storageOptions, blobId) ?: return null
-        return Channels.newInputStream(readChannel)
+        return load(storageOptions, blobId, sizeThreshold)
     }
 
     override fun store(cacheKey: String, contents: ByteArray): Boolean {
@@ -103,14 +102,19 @@ internal class GcpStorageService(
         // Need full control for updating metadata
         private const val STORAGE_FULL_CONTROL = "https://www.googleapis.com/auth/devstorage.full_control"
 
-        private fun load(storage: StorageOptions?, blobId: BlobId): ReadChannel? {
+        private const val BLOB_SIZE_THRESHOLD = 50 * 1024 * 1024L
+
+        private fun load(storage: StorageOptions?, blobId: BlobId, sizeThreshold: Long): InputStream? {
             if (storage == null) return null
             return try {
                 val blob = storage.service.get(blobId) ?: return null
-                val reader = blob.reader()
-                // We don't expect to store objects larger than Int.MAX_VALUE
-                reader.setChunkSize(blob.size.toInt())
-                reader
+                return if (blob.size > sizeThreshold) {
+                    val path = FileHandleInputStream.create()
+                    blob.downloadTo(path)
+                    path.handleInputStream()
+                } else {
+                    blob.getContent().inputStream()
+                }
             } catch (storageException: StorageException) {
                 logger.debug("Unable to load Blob ($blobId)", storageException)
                 null
@@ -141,8 +145,7 @@ internal class GcpStorageService(
         ): StorageOptions? {
             val credentials = credentials(gcpCredentials, isPushSupported) ?: return null
             val retrySettings = RetrySettings.newBuilder()
-            // We don't want retries.
-            retrySettings.maxAttempts = 0
+            retrySettings.maxAttempts = 3
             return StorageOptions.newBuilder().setCredentials(credentials)
                 .setStorageRetryStrategy(StorageRetryStrategy.getUniformStorageRetryStrategy()).setProjectId(projectId)
                 .setRetrySettings(retrySettings.build())

gcpbuildcache/src/test/kotlin/androidx/build/gradle/gcpbuildcache/GcpStorageServiceTest.kt

@@ -35,7 +35,8 @@ class GcpStorageServiceTest {
             bucketName = BUCKET_NAME,
             gcpCredentials = ExportedKeyGcpCredentials(File(serviceAccountPath!!)),
             isPush = true,
-            isEnabled = true
+            isEnabled = true,
+            sizeThreshold = 0L
         )
         storageService.use {
             val cacheKey = "test-store.txt"
@@ -54,7 +55,8 @@ class GcpStorageServiceTest {
             bucketName = BUCKET_NAME,
             gcpCredentials = ExportedKeyGcpCredentials(File(serviceAccountPath!!)),
             isPush = true,
-            isEnabled = true
+            isEnabled = true,
+            sizeThreshold = 0L
         )
         storageService.use {
             val cacheKey = "test-load.txt"
@@ -76,7 +78,8 @@ class GcpStorageServiceTest {
             bucketName = BUCKET_NAME,
             gcpCredentials = ExportedKeyGcpCredentials(File(serviceAccountPath!!)),
             isPush = false,
-            isEnabled = true
+            isEnabled = true,
+            sizeThreshold = 0L
         )
         storageService.use {
             val cacheKey = "test-store-no-push.txt"
@@ -94,14 +97,16 @@ class GcpStorageServiceTest {
             bucketName = BUCKET_NAME,
             gcpCredentials = ExportedKeyGcpCredentials(File(serviceAccountPath!!)),
             isPush = true,
-            isEnabled = true
+            isEnabled = true,
+            sizeThreshold = 0L
         )
         val readOnlyStorageService = GcpStorageService(
             projectId = PROJECT_ID,
             bucketName = BUCKET_NAME,
             gcpCredentials = ExportedKeyGcpCredentials(File(serviceAccountPath)),
             isPush = false,
-            isEnabled = true
+            isEnabled = true,
+            sizeThreshold = 0L
         )
         storageService.use {
             readOnlyStorageService.use {
@@ -125,7 +130,8 @@ class GcpStorageServiceTest {
             bucketName = BUCKET_NAME,
             gcpCredentials = ExportedKeyGcpCredentials(File(serviceAccountPath!!)),
             isPush = true,
-            isEnabled = false
+            isEnabled = false,
+            sizeThreshold = 0L
         )
         storageService.use {
             val cacheKey = "test-store-disabled.txt"