bzlmod: Add --registry flag

(#13316)

This flag is repeatable and used by ModuleFileFunction to determine where to look for modules.

This is not yet testable with an integration test since this code path isn't hooked into production yet (we'll probably need a flag for that).

PiperOrigin-RevId: 383385942

src/main/java/com/google/devtools/build/lib/bazel/BUILD

@@ -26,6 +26,8 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib/analysis:analysis_cluster",
         "//src/main/java/com/google/devtools/build/lib/analysis:blaze_directories",
         "//src/main/java/com/google/devtools/build/lib/analysis:config/build_configuration",
+        "//src/main/java/com/google/devtools/build/lib/bazel/bzlmod:registry",
+        "//src/main/java/com/google/devtools/build/lib/bazel/bzlmod:resolution",
         "//src/main/java/com/google/devtools/build/lib/bazel/commands",
         "//src/main/java/com/google/devtools/build/lib/bazel/repository",
         "//src/main/java/com/google/devtools/build/lib/bazel/repository/cache",

src/main/java/com/google/devtools/build/lib/bazel/BazelRepositoryModule.java

@@ -25,6 +25,11 @@
 import com.google.devtools.build.lib.analysis.ConfiguredRuleClassProvider;
 import com.google.devtools.build.lib.analysis.RuleDefinition;
 import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
+import com.google.devtools.build.lib.bazel.bzlmod.DiscoveryFunction;
+import com.google.devtools.build.lib.bazel.bzlmod.ModuleFileFunction;
+import com.google.devtools.build.lib.bazel.bzlmod.RegistryFactory;
+import com.google.devtools.build.lib.bazel.bzlmod.RegistryFactoryImpl;
+import com.google.devtools.build.lib.bazel.bzlmod.SelectionFunction;
 import com.google.devtools.build.lib.bazel.commands.FetchCommand;
 import com.google.devtools.build.lib.bazel.commands.SyncCommand;
 import com.google.devtools.build.lib.bazel.repository.LocalConfigPlatformFunction;
@@ -87,6 +92,7 @@
 import java.io.IOException;
 import java.lang.reflect.InvocationTargetException;
 import java.util.LinkedHashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
@@ -98,6 +104,10 @@ public class BazelRepositoryModule extends BlazeModule {
   // Default location (relative to output user root) of the repository cache.
   public static final String DEFAULT_CACHE_LOCATION = "cache/repos/v1";
 
+  // Default list of registries.
+  public static final ImmutableList<String> DEFAULT_REGISTRIES =
+      ImmutableList.of("https://bcr.bazel.build/");
+
   // 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);
@@ -115,6 +125,7 @@ public class BazelRepositoryModule extends BlazeModule {
   private Optional<RootedPath> resolvedFileReplacingWorkspace = Optional.empty();
   private Set<String> outputVerificationRules = ImmutableSet.of();
   private FileSystem filesystem;
+  private List<String> registries;
   // We hold the precomputed value of the managed directories here, so that the dependency
   // on WorkspaceFileValue is not registered for each FileStateValue.
   private final ManagedDirectoriesKnowledgeImpl managedDirectoriesKnowledge;
@@ -202,6 +213,13 @@ public void workspaceInit(
             managedDirectoriesKnowledge,
             BazelSkyframeExecutorConstants.EXTERNAL_PACKAGE_HELPER);
     builder.addSkyFunction(SkyFunctions.REPOSITORY_DIRECTORY, repositoryDelegatorFunction);
+    RegistryFactory registryFactory =
+        new RegistryFactoryImpl(new HttpDownloader(), clientEnvironmentSupplier);
+    builder.addSkyFunction(
+        SkyFunctions.MODULE_FILE,
+        new ModuleFileFunction(registryFactory, directories.getWorkspace()));
+    builder.addSkyFunction(SkyFunctions.DISCOVERY, new DiscoveryFunction());
+    builder.addSkyFunction(SkyFunctions.SELECTION, new SelectionFunction());
     filesystem = runtime.getFileSystem();
   }
 
@@ -335,6 +353,12 @@ public void beforeCommand(CommandEnvironment env) throws AbruptExitException {
         overrides = ImmutableMap.of();
       }
 
+      if (repoOptions.registries != null && !repoOptions.registries.isEmpty()) {
+        registries = repoOptions.registries;
+      } else {
+        registries = DEFAULT_REGISTRIES;
+      }
+
       if (!Strings.isNullOrEmpty(repoOptions.repositoryHashFile)) {
         Path hashFile;
         if (env.getWorkspace() != null) {
@@ -394,7 +418,8 @@ public ImmutableList<Injected> getPrecomputedValues() {
             RepositoryDelegatorFunction.DONT_FETCH_UNCONDITIONALLY),
         PrecomputedValue.injected(
             RepositoryDelegatorFunction.DEPENDENCY_FOR_UNCONDITIONAL_CONFIGURING,
-            RepositoryDelegatorFunction.DONT_FETCH_UNCONDITIONALLY));
+            RepositoryDelegatorFunction.DONT_FETCH_UNCONDITIONALLY),
+        PrecomputedValue.injected(ModuleFileFunction.REGISTRIES, registries));
   }
 
   @Override

src/main/java/com/google/devtools/build/lib/bazel/repository/BUILD

@@ -44,7 +44,6 @@ java_library(
         "//src/main/java/com/google/devtools/build/skyframe:skyframe-objects",
         "//src/main/java/com/google/devtools/common/options",
         "//src/main/java/net/starlark/java/eval",
-        "//src/main/java/net/starlark/java/syntax",
         "//third_party:apache_commons_compress",
         "//third_party:auto_value",
         "//third_party:flogger",

src/main/java/com/google/devtools/build/lib/bazel/repository/RepositoryOptions.java

@@ -46,6 +46,18 @@ public class RepositoryOptions extends OptionsBase {
               + "as argument requests the cache to be disabled.")
   public PathFragment experimentalRepositoryCache;
 
+  @Option(
+      name = "registry",
+      defaultValue = "null",
+      allowMultiple = true,
+      documentationCategory = OptionDocumentationCategory.BAZEL_CLIENT_OPTIONS,
+      effectTags = {OptionEffectTag.CHANGES_INPUTS},
+      help =
+          "Specifies the registries to use to locate Bazel module dependencies. The order is"
+              + " important: modules will be looked up in earlier registries first, and only fall"
+              + " back to later registries when they're missing from the earlier ones.")
+  public List<String> registries;
+
   @Option(
       name = "experimental_repository_cache_hardlinks",
       defaultValue = "false",