Made HttpDownloader download calls non-static.

To set and use a RepositoryCache instance in HttpDownloader while parsing the command line options, we can pass an AtomicReference<HttpDownloader> instance from BazelRepositoryModule to the HttpArchiveFunctions. However, we'll need to change HttpDownloader download() calls to be non-static in order to initialize an instance of HttpDownloader in BazelRepositoryModule.

Remaining TODOs:

- RepositoryCache implementation and unit testing
- RepositoryCache lockfiles
- RepositoryCache integration testing

GITHUB: #1752

--
MOS_MIGRATED_REVID=136593517

12 files changed, 101 insertions, 96 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/BUILD b/src/main/java/com/google/devtools/build/lib/BUILD
index 9f6783487c..111786eee2 100644
--- a/src/main/java/com/google/devtools/build/lib/BUILD
+++ b/src/main/java/com/google/devtools/build/lib/BUILD
@@ -608,6 +608,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib/actions",
         "//src/main/java/com/google/devtools/build/lib/bazel/dash",
         "//src/main/java/com/google/devtools/build/lib/bazel/repository/cache",
+        "//src/main/java/com/google/devtools/build/lib/bazel/repository/downloader",
         "//src/main/java/com/google/devtools/build/lib/remote",
         "//src/main/java/com/google/devtools/build/lib/sandbox",
         "//src/main/java/com/google/devtools/build/lib/ssd",
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/BazelRepositoryModule.java b/src/main/java/com/google/devtools/build/lib/bazel/BazelRepositoryModule.java
index 282508b9e5..da9b9b9b25 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/BazelRepositoryModule.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/BazelRepositoryModule.java
@@ -31,6 +31,7 @@ import com.google.devtools.build.lib.bazel.repository.NewGitRepositoryFunction;
 import com.google.devtools.build.lib.bazel.repository.NewHttpArchiveFunction;
 import com.google.devtools.build.lib.bazel.repository.RepositoryOptions;
 import com.google.devtools.build.lib.bazel.repository.cache.RepositoryCache;
+import com.google.devtools.build.lib.bazel.repository.downloader.HttpDownloader;
 import com.google.devtools.build.lib.bazel.repository.skylark.SkylarkRepositoryFunction;
 import com.google.devtools.build.lib.bazel.repository.skylark.SkylarkRepositoryModule;
 import com.google.devtools.build.lib.bazel.rules.android.AndroidNdkRepositoryFunction;
@@ -81,21 +82,22 @@ public class BazelRepositoryModule extends BlazeModule {
   // A map of repository handlers that can be looked up by rule class name.
   private final ImmutableMap<String, RepositoryFunction> repositoryHandlers;
   private final AtomicBoolean isFetch = new AtomicBoolean(false);
-  private final SkylarkRepositoryFunction skylarkRepositoryFunction =
-      new SkylarkRepositoryFunction();
+  private final SkylarkRepositoryFunction skylarkRepositoryFunction;
   private final RepositoryDelegatorFunction delegator;
-  private final AtomicReference<RepositoryCache> repositoryCache = new AtomicReference<>();
+  private final AtomicReference<HttpDownloader> httpDownloader =
+      new AtomicReference<>(new HttpDownloader());
 
   public BazelRepositoryModule() {
+    this.skylarkRepositoryFunction = new SkylarkRepositoryFunction(httpDownloader);
     this.repositoryHandlers =
         ImmutableMap.<String, RepositoryFunction>builder()
             .put(LocalRepositoryRule.NAME, new LocalRepositoryFunction())
-            .put(HttpArchiveRule.NAME, new HttpArchiveFunction(repositoryCache))
+            .put(HttpArchiveRule.NAME, new HttpArchiveFunction(httpDownloader))
             .put(GitRepositoryRule.NAME, new GitRepositoryFunction())
-            .put(HttpJarRule.NAME, new HttpJarFunction())
-            .put(HttpFileRule.NAME, new HttpFileFunction())
-            .put(MavenJarRule.NAME, new MavenJarFunction())
-            .put(NewHttpArchiveRule.NAME, new NewHttpArchiveFunction())
+            .put(HttpJarRule.NAME, new HttpJarFunction(httpDownloader))
+            .put(HttpFileRule.NAME, new HttpFileFunction(httpDownloader))
+            .put(MavenJarRule.NAME, new MavenJarFunction(httpDownloader))
+            .put(NewHttpArchiveRule.NAME, new NewHttpArchiveFunction(httpDownloader))
             .put(NewGitRepositoryRule.NAME, new NewGitRepositoryFunction())
             .put(NewLocalRepositoryRule.NAME, new NewLocalRepositoryFunction())
             .put(AndroidSdkRepositoryRule.NAME, new AndroidSdkRepositoryFunction())
@@ -171,7 +173,8 @@ public class BazelRepositoryModule extends BlazeModule {
 
     RepositoryOptions repoOptions = optionsProvider.getOptions(RepositoryOptions.class);
     if (repoOptions != null && repoOptions.experimentalRepositoryCache != null) {
-      repositoryCache.set(new RepositoryCache(repoOptions.experimentalRepositoryCache));
+      httpDownloader.get().setRepositoryCache(
+          new RepositoryCache(repoOptions.experimentalRepositoryCache));
     }
   }
 
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/repository/HttpArchiveFunction.java b/src/main/java/com/google/devtools/build/lib/bazel/repository/HttpArchiveFunction.java
index ca9a446fd0..059c5987fd 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/repository/HttpArchiveFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/repository/HttpArchiveFunction.java
@@ -16,7 +16,6 @@ package com.google.devtools.build.lib.bazel.repository;
 
 import com.google.devtools.build.lib.analysis.BlazeDirectories;
 import com.google.devtools.build.lib.analysis.RuleDefinition;
-import com.google.devtools.build.lib.bazel.repository.cache.RepositoryCache;
 import com.google.devtools.build.lib.bazel.repository.downloader.HttpDownloader;
 import com.google.devtools.build.lib.bazel.rules.workspace.HttpArchiveRule;
 import com.google.devtools.build.lib.packages.Rule;
@@ -39,17 +38,10 @@ import java.util.concurrent.atomic.AtomicReference;
  */
 public class HttpArchiveFunction extends RepositoryFunction {
 
-  private final AtomicReference<RepositoryCache> repositoryCache;
+  protected final AtomicReference<HttpDownloader> httpDownloader;
 
-  protected HttpArchiveFunction() {
-    repositoryCache = new AtomicReference<>();
-  }
-
-  /**
-   * @param repositoryCache the reference to the repository cache.
-   */
-  public HttpArchiveFunction(AtomicReference<RepositoryCache> repositoryCache) {
-    this.repositoryCache = repositoryCache;
+  public HttpArchiveFunction(AtomicReference<HttpDownloader> httpDownloader) {
+    this.httpDownloader = httpDownloader;
   }
 
   @Override
@@ -70,18 +62,16 @@ public class HttpArchiveFunction extends RepositoryFunction {
   public SkyValue fetch(
       Rule rule, Path outputDirectory, BlazeDirectories directories, Environment env)
           throws RepositoryFunctionException, InterruptedException {
-    // The output directory is always under .external-repository (to stay out of the way of
+    // The output directory is always under output_base/external (to stay out of the way of
     // artifacts from this repository) and uses the rule's name to avoid conflicts with other
     // remote repository rules. For example, suppose you had the following WORKSPACE file:
     //
     // http_archive(name = "png", url = "http://example.com/downloads/png.tar.gz", sha256 = "...")
     //
-    // This would download png.tar.gz to .external-repository/png/png.tar.gz.
+    // This would download png.tar.gz to output_base/external/png/png.tar.gz.
     createDirectory(outputDirectory);
-    Path downloadedPath = (repositoryCache == null || repositoryCache.get() == null)
-        ? HttpDownloader.download(rule, outputDirectory, env.getListener(), clientEnvironment)
-        : HttpDownloader.download(rule, outputDirectory, env.getListener(), clientEnvironment,
-            repositoryCache.get());
+    Path downloadedPath = httpDownloader.get().download(rule, outputDirectory,
+        env.getListener(), clientEnvironment);
 
     DecompressorValue.decompress(getDescriptor(rule, downloadedPath, outputDirectory));
     return RepositoryDirectoryValue.create(outputDirectory);
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/repository/HttpFileFunction.java b/src/main/java/com/google/devtools/build/lib/bazel/repository/HttpFileFunction.java
index 1ded55400b..be19da3d08 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/repository/HttpFileFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/repository/HttpFileFunction.java
@@ -15,6 +15,7 @@
 package com.google.devtools.build.lib.bazel.repository;
 
 import com.google.devtools.build.lib.analysis.RuleDefinition;
+import com.google.devtools.build.lib.bazel.repository.downloader.HttpDownloader;
 import com.google.devtools.build.lib.bazel.rules.workspace.HttpFileRule;
 import com.google.devtools.build.lib.packages.Rule;
 import com.google.devtools.build.lib.rules.repository.WorkspaceAttributeMapper;
@@ -22,11 +23,17 @@ import com.google.devtools.build.lib.syntax.EvalException;
 import com.google.devtools.build.lib.syntax.Type;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.skyframe.SkyFunctionException.Transience;
+import java.util.concurrent.atomic.AtomicReference;
 
 /**
  * Downloads a jar file from a URL.
  */
 public class HttpFileFunction extends HttpArchiveFunction {
+
+  public HttpFileFunction(AtomicReference<HttpDownloader> httpDownloader) {
+    super(httpDownloader);
+  }
+
   @Override
   protected DecompressorDescriptor getDescriptor(Rule rule, Path downloadPath, Path outputDirectory)
       throws RepositoryFunctionException {
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/repository/HttpJarFunction.java b/src/main/java/com/google/devtools/build/lib/bazel/repository/HttpJarFunction.java
index a09ee1c8d0..d260a3957b 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/repository/HttpJarFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/repository/HttpJarFunction.java
@@ -15,14 +15,21 @@
 package com.google.devtools.build.lib.bazel.repository;
 
 import com.google.devtools.build.lib.analysis.RuleDefinition;
+import com.google.devtools.build.lib.bazel.repository.downloader.HttpDownloader;
 import com.google.devtools.build.lib.bazel.rules.workspace.HttpJarRule;
 import com.google.devtools.build.lib.packages.Rule;
 import com.google.devtools.build.lib.vfs.Path;
+import java.util.concurrent.atomic.AtomicReference;
 
 /**
  * Downloads a jar file from a URL.
  */
 public class HttpJarFunction extends HttpArchiveFunction {
+
+  public HttpJarFunction(AtomicReference<HttpDownloader> httpDownloader) {
+    super(httpDownloader);
+  }
+
   @Override
   protected DecompressorDescriptor getDescriptor(Rule rule, Path downloadPath, Path outputDirectory)
       throws RepositoryFunctionException {
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/repository/MavenJarFunction.java b/src/main/java/com/google/devtools/build/lib/bazel/repository/MavenJarFunction.java
index a41f3ab076..60ed5558f3 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/repository/MavenJarFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/repository/MavenJarFunction.java
@@ -35,6 +35,7 @@ import com.google.devtools.build.skyframe.SkyFunctionException.Transience;
 import com.google.devtools.build.skyframe.SkyValue;
 import java.io.IOException;
 import java.util.Map;
+import java.util.concurrent.atomic.AtomicReference;
 import javax.annotation.Nullable;
 import org.apache.maven.settings.Server;
 import org.eclipse.aether.RepositorySystem;
@@ -53,6 +54,11 @@ import org.eclipse.aether.resolution.ArtifactResult;
  * Implementation of maven_jar.
  */
 public class MavenJarFunction extends HttpArchiveFunction {
+
+  public MavenJarFunction(AtomicReference<HttpDownloader> httpDownloader) {
+    super(httpDownloader);
+  }
+
   private static final String DEFAULT_SERVER = "default";
 
   @Override
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/repository/NewHttpArchiveFunction.java b/src/main/java/com/google/devtools/build/lib/bazel/repository/NewHttpArchiveFunction.java
index 04ad0b708c..24562c3c21 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/repository/NewHttpArchiveFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/repository/NewHttpArchiveFunction.java
@@ -29,7 +29,7 @@ import com.google.devtools.build.skyframe.SkyFunctionException.Transience;
 import com.google.devtools.build.skyframe.SkyValue;
 
 import java.io.IOException;
-
+import java.util.concurrent.atomic.AtomicReference;
 import javax.annotation.Nullable;
 
 /**
@@ -38,6 +38,10 @@ import javax.annotation.Nullable;
  */
 public class NewHttpArchiveFunction extends HttpArchiveFunction {
 
+  public NewHttpArchiveFunction(AtomicReference<HttpDownloader> httpDownloader) {
+    super(httpDownloader);
+  }
+
   @Nullable
   @Override
   public SkyValue fetch(
@@ -57,7 +61,7 @@ public class NewHttpArchiveFunction extends HttpArchiveFunction {
     }
 
     // Download.
-    Path downloadedPath = HttpDownloader.download(
+    Path downloadedPath = httpDownloader.get().download(
         rule, outputDirectory, env.getListener(), clientEnvironment);
 
     // Decompress.
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/repository/downloader/HttpDownloader.java b/src/main/java/com/google/devtools/build/lib/bazel/repository/downloader/HttpDownloader.java
index 5f738cd1e4..c25699ae76 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/repository/downloader/HttpDownloader.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/repository/downloader/HttpDownloader.java
@@ -40,8 +40,6 @@ import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
 
-import javax.annotation.Nullable;
-
 /**
  * Helper class for downloading a file from a URL.
  */
@@ -51,28 +49,13 @@ public class HttpDownloader {
   private static final String UNITS = " KMGTPEY";
   private static final double LOG_OF_KB = Math.log(1024);
 
-  private final String urlString;
-  private final String sha256;
-  private final String type;
-  private final Path outputDirectory;
-  private final EventHandler eventHandler;
   private final ScheduledExecutorService scheduler;
-  private final Map<String, String> clientEnv;
 
-  private HttpDownloader(
-      EventHandler eventHandler, String urlString, String sha256, Path outputDirectory,
-      String type, Map<String, String> clientEnv) {
-    this.urlString = urlString;
-    this.sha256 = sha256;
-    this.outputDirectory = outputDirectory;
-    this.eventHandler = eventHandler;
+  public HttpDownloader() {
     this.scheduler = Executors.newScheduledThreadPool(1);
-    this.type = type;
-    this.clientEnv = clientEnv;
   }
 
-  @Nullable
-  public static Path download(
+  public Path download(
       Rule rule, Path outputDirectory, EventHandler eventHandler, Map<String, String> clientEnv)
       throws RepositoryFunctionException, InterruptedException {
     WorkspaceAttributeMapper mapper = WorkspaceAttributeMapper.of(rule);
@@ -89,42 +72,11 @@ public class HttpDownloader {
     }
 
     try {
-      return new HttpDownloader(eventHandler, url, sha256, outputDirectory, type, clientEnv)
-          .download();
-    } catch (IOException e) {
-      throw new RepositoryFunctionException(new IOException("Error downloading from "
-          + url + " to " + outputDirectory + ": " + e.getMessage()),
-          SkyFunctionException.Transience.TRANSIENT);
-    }
-  }
-
-  @SuppressWarnings("unused")
-  @Nullable
-  public static Path download(
-      Rule rule, Path outputDirectory, EventHandler eventHandler, Map<String, String> clientEnv,
-      RepositoryCache repositoryCache)
-      throws RepositoryFunctionException, InterruptedException {
-
-    /* TODO(jingwen): No-op with the cache controller for now.
-     * This will be the place where we detect cache hits with the sha256 value
-     * and copy the values accordingly.
-     * 
-     * For now, delegating operation to the original download method.
-     */
-    return download(rule, outputDirectory, eventHandler, clientEnv);
-  }
-
-  @Nullable
-  public static Path download(
-      String url, String sha256, String type, Path output, EventHandler eventHandler, Map<String,
-      String> clientEnv)
-      throws RepositoryFunctionException, InterruptedException {
-    try {
-      return new HttpDownloader(eventHandler, url, sha256, output, type, clientEnv).download();
+      return download(url, sha256, type, outputDirectory, eventHandler, clientEnv);
     } catch (IOException e) {
       throw new RepositoryFunctionException(
           new IOException(
-              "Error downloading from " + url + " to " + output + ": " + e.getMessage()),
+              "Error downloading from " + url + " to " + outputDirectory + ": " + e.getMessage()),
           SkyFunctionException.Transience.TRANSIENT);
     }
   }
@@ -132,7 +84,10 @@ public class HttpDownloader {
   /**
    * Attempt to download a file from the repository's URL. Returns the path to the file downloaded.
    */
-  public Path download() throws IOException, InterruptedException {
+  public Path download(
+      String urlString, String sha256, String type, Path outputDirectory,
+      EventHandler eventHandler, Map<String, String> clientEnv)
+          throws IOException, InterruptedException {
     URL url = new URL(urlString);
     Path destination;
     if (type == null) {
@@ -160,10 +115,10 @@ public class HttpDownloader {
     }
 
     AtomicInteger totalBytes = new AtomicInteger(0);
-    final ScheduledFuture<?> loggerHandle = getLoggerHandle(totalBytes);
+    final ScheduledFuture<?> loggerHandle = getLoggerHandle(totalBytes, eventHandler, urlString);
 
     try (OutputStream out = destination.getOutputStream();
-         HttpConnection connection = HttpConnection.createAndConnect(url, this.clientEnv)) {
+         HttpConnection connection = HttpConnection.createAndConnect(url, clientEnv)) {
       InputStream inputStream = connection.getInputStream();
       int read;
       byte[] buf = new byte[BUFFER_SIZE];
@@ -191,11 +146,11 @@ public class HttpDownloader {
       }, 0, TimeUnit.SECONDS);
     }
 
-    compareHashes(destination);
+    compareHashes(destination, sha256);
     return destination;
   }
 
-  private void compareHashes(Path destination) throws IOException {
+  private void compareHashes(Path destination, String sha256) throws IOException {
     if (sha256.isEmpty()) {
       return;
     }
@@ -214,7 +169,8 @@ public class HttpDownloader {
     }
   }
 
-  private ScheduledFuture<?> getLoggerHandle(final AtomicInteger totalBytes) {
+  private ScheduledFuture<?> getLoggerHandle(
+      final AtomicInteger totalBytes, EventHandler eventHandler, String urlString) {
     final Runnable logger = new Runnable() {
       @Override
       public void run() {
@@ -256,4 +212,8 @@ public class HttpDownloader {
     }
     return hasher.hash().toString();
   }
+
+  public void setRepositoryCache(@SuppressWarnings("unused") RepositoryCache repositoryCache) {
+    // TODO(jingwen): Implement repository cache bridge
+  }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryContext.java b/src/main/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryContext.java
index 4614b21d0a..69ffa1c402 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryContext.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryContext.java
@@ -55,6 +55,7 @@ import java.io.IOException;
 import java.io.OutputStream;
 import java.nio.charset.StandardCharsets;
 import java.util.Map;
+import java.util.concurrent.atomic.AtomicReference;
 
 /** Skylark API for the repository_rule's context. */
 @SkylarkModule(
@@ -73,6 +74,7 @@ public class SkylarkRepositoryContext {
   private final SkylarkClassObject attrObject;
   private final SkylarkOS osObject;
   private final Environment env;
+  private final AtomicReference<HttpDownloader> httpDownloader;
 
   /**
    * Convert attribute name from native naming convention to Skylark naming convention.
@@ -92,12 +94,14 @@ public class SkylarkRepositoryContext {
    * argument).
    */
   SkylarkRepositoryContext(
-      Rule rule, Path outputDirectory, Environment environment, Map<String, String> env)
+      Rule rule, Path outputDirectory, Environment environment,
+      Map<String, String> env, AtomicReference<HttpDownloader> httpDownloader)
       throws EvalException {
     this.rule = rule;
     this.outputDirectory = outputDirectory;
     this.env = environment;
     this.osObject = new SkylarkOS(env);
+    this.httpDownloader = httpDownloader;
     WorkspaceAttributeMapper attrs = WorkspaceAttributeMapper.of(rule);
     ImmutableMap.Builder<String, Object> attrBuilder = new ImmutableMap.Builder<>();
     for (String name : attrs.getAttributeNames()) {
@@ -485,7 +489,7 @@ public class SkylarkRepositoryContext {
     try {
       checkInOutputDirectory(outputPath);
       makeDirectories(outputPath.getPath());
-      HttpDownloader.download(url, sha256, null, outputPath.getPath(), env.getListener(),
+      httpDownloader.get().download(url, sha256, null, outputPath.getPath(), env.getListener(),
           osObject.getEnvironmentVariables());
       if (executable) {
         outputPath.getPath().setExecutable(true);
@@ -562,9 +566,13 @@ public class SkylarkRepositoryContext {
     SkylarkPath outputPath = getPath("download_and_extract()", output);
     checkInOutputDirectory(outputPath);
     createDirectory(outputPath.getPath());
-    Path downloadedPath = HttpDownloader
-        .download(url, sha256, type, outputPath.getPath(), env.getListener(),
-            osObject.getEnvironmentVariables());
+    Path downloadedPath;
+    try {
+      downloadedPath = httpDownloader.get().download(url, sha256, type, outputPath.getPath(),
+          env.getListener(), osObject.getEnvironmentVariables());
+    } catch (IOException e) {
+      throw new RepositoryFunctionException(e, Transience.TRANSIENT);
+    }
     DecompressorValue.decompress(
         DecompressorDescriptor.builder()
             .setTargetKind(rule.getTargetKind())
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryFunction.java b/src/main/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryFunction.java
index 0d3ba70ef1..71a8fdacd9 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryFunction.java
@@ -18,6 +18,7 @@ import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.devtools.build.lib.analysis.BlazeDirectories;
 import com.google.devtools.build.lib.analysis.RuleDefinition;
+import com.google.devtools.build.lib.bazel.repository.downloader.HttpDownloader;
 import com.google.devtools.build.lib.events.Location;
 import com.google.devtools.build.lib.packages.Rule;
 import com.google.devtools.build.lib.rules.repository.RepositoryDirectoryValue;
@@ -36,7 +37,7 @@ import com.google.devtools.build.skyframe.SkyValue;
 
 import java.io.IOException;
 import java.util.Map;
-
+import java.util.concurrent.atomic.AtomicReference;
 import javax.annotation.Nullable;
 
 /**
@@ -55,6 +56,12 @@ public class SkylarkRepositoryFunction extends RepositoryFunction {
     }
   }
 
+  private final AtomicReference<HttpDownloader> httpDownloader;
+
+  public SkylarkRepositoryFunction(AtomicReference<HttpDownloader> httpDownloader) {
+    this.httpDownloader = httpDownloader;
+  }
+
   /**
    * Skylark repository context functions can throw the result of this function to notify the
    * SkylarkRepositoryFunction that a dependency was missing and the evaluation of the function must
@@ -89,8 +96,8 @@ public class SkylarkRepositoryFunction extends RepositoryFunction {
               .setSkylark()
               .setEventHandler(env.getListener())
               .build();
-      SkylarkRepositoryContext skylarkRepositoryContext =
-          new SkylarkRepositoryContext(rule, outputDirectory, env, getClientEnvironment());
+      SkylarkRepositoryContext skylarkRepositoryContext = new SkylarkRepositoryContext(
+          rule, outputDirectory, env, getClientEnvironment(), httpDownloader);
 
       // This has side-effect, we don't care about the output.
       // Also we do a lot of stuff in there, maybe blocking operations and we should certainly make
diff --git a/src/test/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryContextTest.java b/src/test/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryContextTest.java
index 79b8fed690..6d19070576 100644
--- a/src/test/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryContextTest.java
+++ b/src/test/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryContextTest.java
@@ -20,6 +20,7 @@ import static org.junit.Assert.fail;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.io.CharStreams;
+import com.google.devtools.build.lib.bazel.repository.downloader.HttpDownloader;
 import com.google.devtools.build.lib.events.Location;
 import com.google.devtools.build.lib.packages.Attribute;
 import com.google.devtools.build.lib.packages.Package;
@@ -40,6 +41,7 @@ import java.io.IOException;
 import java.io.InputStreamReader;
 import java.nio.charset.StandardCharsets;
 import java.util.Map;
+import java.util.concurrent.atomic.AtomicReference;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -87,12 +89,15 @@ public class SkylarkRepositoryContextTest {
             .externalPackageData()
             .createAndAddRepositoryRule(
                 packageBuilder, buildRuleClass(attributes), null, kwargs, ast);
+    AtomicReference<HttpDownloader> httpDownloader =
+        new AtomicReference<>(Mockito.mock(HttpDownloader.class));
     context =
         new SkylarkRepositoryContext(
             rule,
             outputDirectory,
             Mockito.mock(SkyFunction.Environment.class),
-            ImmutableMap.of("FOO", "BAR"));
+            ImmutableMap.of("FOO", "BAR"),
+            httpDownloader);
   }
 
   protected void setUpContexForRule(String name) throws Exception {
diff --git a/src/test/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryIntegrationTest.java b/src/test/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryIntegrationTest.java
index 9b63536d30..e0e0b857ea 100644
--- a/src/test/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryIntegrationTest.java
+++ b/src/test/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryIntegrationTest.java
@@ -22,6 +22,7 @@ import com.google.devtools.build.lib.analysis.ConfiguredRuleClassProvider;
 import com.google.devtools.build.lib.analysis.ConfiguredTarget;
 import com.google.devtools.build.lib.analysis.util.AnalysisMock;
 import com.google.devtools.build.lib.analysis.util.BuildViewTestCase;
+import com.google.devtools.build.lib.bazel.repository.downloader.HttpDownloader;
 import com.google.devtools.build.lib.packages.BuildFileContainsErrorsException;
 import com.google.devtools.build.lib.packages.NoSuchPackageException;
 import com.google.devtools.build.lib.rules.cpp.FdoSupportFunction;
@@ -38,9 +39,11 @@ import com.google.devtools.build.skyframe.SkyFunctionName;
 import java.io.OutputStream;
 import java.nio.charset.StandardCharsets;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicReference;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
+import org.mockito.Mockito;
 
 /**
  * Integration test for skylark repository not as heavyweight than shell integration tests.
@@ -66,8 +69,12 @@ public class SkylarkRepositoryIntegrationTest extends BuildViewTestCase {
     @Override
     public ImmutableMap<SkyFunctionName, SkyFunction> getSkyFunctions() {
       // Add both the local repository and the skylark repository functions
+      // The HttpDownloader mock injected with the SkylarkRepositoryFunction
+      AtomicReference<HttpDownloader> httpDownloader =
+          new AtomicReference<>(Mockito.mock(HttpDownloader.class));
       RepositoryFunction localRepositoryFunction = new LocalRepositoryFunction();
-      SkylarkRepositoryFunction skylarkRepositoryFunction = new SkylarkRepositoryFunction();
+      SkylarkRepositoryFunction skylarkRepositoryFunction =
+          new SkylarkRepositoryFunction(httpDownloader);
       ImmutableMap<String, RepositoryFunction> repositoryHandlers =
           ImmutableMap.of(LocalRepositoryRule.NAME, localRepositoryFunction);