Simplify service registration and create a way for a service to supply options.

The service registry is not needed: the service component can simply pass in a list of instantiated services into BlazeRuntime.main(), and the lookup can be done by iterating the list (there will only be a few of them and the iteration is done at startup, so performance isn't a concern). The design mirrors the way BlazeModules work.

Also introduce OptionsSupplier, a super-interface of BlazeModule and BlazeService containing only the methods related to options. This provides a uniform way to collect them from both components.

PiperOrigin-RevId: 823940987
Change-Id: Ifc414b211d4afc79737941987ec1b6e315772175

Author: tjgq

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

@@ -299,6 +299,22 @@ java_library(
     ],
 )
 
+java_library(
+    name = "runtime/options_supplier",
+    srcs = ["runtime/OptionsSupplier.java"],
+    deps = ["//src/main/java/com/google/devtools/common/options"],
+)
+
+java_library(
+    name = "runtime/blaze_service",
+    srcs = ["runtime/BlazeService.java"],
+    deps = [
+        ":runtime/options_supplier",
+        "//src/main/java/com/google/devtools/common/options",
+        "//third_party:guava",
+    ],
+)
+
 java_library(
     name = "runtime",
     srcs = glob(
@@ -312,6 +328,7 @@ java_library(
             "buildtool/BaselineCLDiffEvent.java",
             "buildtool/SymlinkForest.java",
             "runtime/BlazeCommandResult.java",
+            "runtime/BlazeService.java",
             "runtime/CommandDispatcher.java",
             "runtime/CommandLinePathFactory.java",
             "runtime/ConfigFlagDefinitions.java",
@@ -321,6 +338,7 @@ java_library(
             "runtime/MemoryPressureEvent.java",
             "runtime/MemoryPressureOptions.java",
             "runtime/MemoryPressureStatCollector.java",
+            "runtime/OptionsSupplier.java",
             "runtime/StarlarkOptionsParser.java",
             "runtime/TestSummaryOptions.java",
         ],
@@ -332,10 +350,12 @@ java_library(
         ":keep-going-option",
         ":loading-phase-threads-option",
         ":runtime/blaze_command_result",
+        ":runtime/blaze_service",
         ":runtime/command_dispatcher",
         ":runtime/command_line_path_factory",
         ":runtime/config_flag_definitions",
         ":runtime/memory_pressure",
+        ":runtime/options_supplier",
         ":runtime/test_summary_options",
         ":starlark_options_parser",
         "//src/main/java/com/google/devtools/build/lib/actions",

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

@@ -169,6 +169,7 @@ java_library(
         ":repository_module",
         ":spawn_log_module",
         "//src/main/java/com/google/devtools/build/lib:runtime",
+        "//src/main/java/com/google/devtools/build/lib:runtime/blaze_service",
         "//src/main/java/com/google/devtools/build/lib/analysis:blaze_version_info",
         "//src/main/java/com/google/devtools/build/lib/authandtls/credentialhelper:credential_module",
         "//src/main/java/com/google/devtools/build/lib/bazel/bzlmod:bazel_lockfile_module",

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

@@ -19,6 +19,7 @@
 import com.google.devtools.build.lib.authandtls.credentialhelper.CredentialModule;
 import com.google.devtools.build.lib.runtime.BlazeModule;
 import com.google.devtools.build.lib.runtime.BlazeRuntime;
+import com.google.devtools.build.lib.runtime.BlazeService;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.Properties;
@@ -99,9 +100,12 @@ public final class Bazel {
           com.google.devtools.build.lib.metrics.PostGCMemoryUseRecorder.GcAfterBuildModule.class,
           com.google.devtools.build.lib.metrics.MetricsModule.class);
 
+  @SuppressWarnings("UnnecessarilyFullyQualified") // Class names fully qualified for clarity.
+  public static final ImmutableList<BlazeService> BAZEL_SERVICES = ImmutableList.of();
+
   public static void main(String[] args) {
     BlazeVersionInfo.setBuildInfo(tryGetBuildInfo());
-    BlazeRuntime.main(BAZEL_MODULES, args);
+    BlazeRuntime.main(BAZEL_MODULES, BAZEL_SERVICES, args);
   }
 
   /**

src/main/java/com/google/devtools/build/lib/runtime/BlazeCommandDispatcher.java

@@ -129,7 +129,7 @@ public OpaqueOptionsData load(BlazeCommand command) {
                   return OptionsParser.getOptionsData(
                       BlazeCommandUtils.getOptions(
                           command.getClass(),
-                          runtime.getBlazeModules(),
+                          runtime.getOptionsSuppliers(),
                           runtime.getRuleClassProvider()));
                 }
               });

src/main/java/com/google/devtools/build/lib/runtime/BlazeCommandUtils.java

@@ -46,21 +46,21 @@ public class BlazeCommandUtils {
   private BlazeCommandUtils() {}
 
   public static ImmutableList<Class<? extends OptionsBase>> getStartupOptions(
-      Iterable<BlazeModule> modules) {
+      Iterable<OptionsSupplier> suppliers) {
     Set<Class<? extends OptionsBase>> options = new HashSet<>(DEFAULT_STARTUP_OPTIONS);
-    for (BlazeModule blazeModule : modules) {
-      Iterables.addAll(options, blazeModule.getStartupOptions());
+    for (OptionsSupplier supplier : suppliers) {
+      Iterables.addAll(options, supplier.getStartupOptions());
     }
 
     return ImmutableList.copyOf(options);
   }
 
   public static ImmutableSet<Class<? extends OptionsBase>> getCommonOptions(
-      Iterable<BlazeModule> modules) {
+      Iterable<OptionsSupplier> suppliers) {
     ImmutableSet.Builder<Class<? extends OptionsBase>> builder = ImmutableSet.builder();
     builder.addAll(COMMON_COMMAND_OPTIONS);
-    for (BlazeModule blazeModule : modules) {
-      builder.addAll(blazeModule.getCommonCommandOptions());
+    for (OptionsSupplier supplier : suppliers) {
+      builder.addAll(supplier.getCommonCommandOptions());
     }
     return builder.build();
   }
@@ -73,26 +73,26 @@ public static ImmutableSet<Class<? extends OptionsBase>> getCommonOptions(
    */
   public static ImmutableList<Class<? extends OptionsBase>> getOptions(
       Class<? extends BlazeCommand> clazz,
-      Iterable<BlazeModule> modules,
+      Iterable<OptionsSupplier> suppliers,
       ConfiguredRuleClassProvider ruleClassProvider) {
     Command commandAnnotation = clazz.getAnnotation(Command.class);
     if (commandAnnotation == null) {
       throw new IllegalStateException("@Command missing for " + clazz.getName());
     }
 
-    Set<Class<? extends OptionsBase>> options = new HashSet<>(getCommonOptions(modules));
+    Set<Class<? extends OptionsBase>> options = new HashSet<>(getCommonOptions(suppliers));
     Collections.addAll(options, commandAnnotation.options());
 
     if (commandAnnotation.usesConfigurationOptions()) {
       options.addAll(ruleClassProvider.getFragmentRegistry().getOptionsClasses());
     }
 
-    for (BlazeModule blazeModule : modules) {
-      Iterables.addAll(options, blazeModule.getCommandOptions(commandAnnotation.name()));
+    for (OptionsSupplier supplier : suppliers) {
+      Iterables.addAll(options, supplier.getCommandOptions(commandAnnotation.name()));
     }
 
     for (Class<? extends BlazeCommand> base : commandAnnotation.inheritsOptionsFrom()) {
-      options.addAll(getOptions(base, modules, ruleClassProvider));
+      options.addAll(getOptions(base, suppliers, ruleClassProvider));
     }
     return ImmutableList.copyOf(options);
   }
@@ -159,15 +159,15 @@ public static String expandHelpTopic(
   public static String getUsage(
       Class<? extends BlazeCommand> commandClass,
       OptionsParser.HelpVerbosity verbosity,
-      Iterable<BlazeModule> blazeModules,
+      Iterable<OptionsSupplier> optionsSuppliers,
       ConfiguredRuleClassProvider ruleClassProvider,
       String productName) {
     Command commandAnnotation = commandClass.getAnnotation(Command.class);
     return BlazeCommandUtils.expandHelpTopic(
         commandAnnotation.name(),
         commandAnnotation.help(),
         commandClass,
-        getOptions(commandClass, blazeModules, ruleClassProvider),
+        getOptions(commandClass, optionsSuppliers, ruleClassProvider),
         verbosity,
         productName);
   }

src/main/java/com/google/devtools/build/lib/runtime/BlazeModule.java

@@ -55,21 +55,20 @@
 import javax.annotation.Nullable;
 
 /**
- * A module Bazel can load at the beginning of its execution. Modules are supplied with extension
- * points to augment the functionality at specific, well-defined places.
+ * Provides the ability to augment the functionality of the Logical Component (LC).
  *
- * <p>The constructors of individual Bazel modules should be empty. All work should be done in the
- * methods (e.g. {@link #blazeStartup}).
+ * <p>The augmentation is done by implementing one or more of the methods in this class, which are
+ * called at well-defined points during the server's lifecycle.
+ *
+ * <p>The set of modules is passed into {@link BlazeRuntime#main} and is fixed for the lifetime of
+ * the server. A module can be obtained by calling {@link BlazeRuntime#getBlazeModule}.
+ *
+ * <p>The constructors of individual Bazel modules must take no arguments and be empty. All work
+ * should be done in the methods (e.g. {@link #blazeStartup}).
  */
-public abstract class BlazeModule {
+public abstract class BlazeModule implements OptionsSupplier {
 
-  /**
-   * Returns the extra startup options this module contributes.
-   *
-   * <p>This method will be called at the beginning of Blaze startup (before {@link #globalInit}).
-   * The startup options need to be parsed very early in the process, which requires this to be
-   * separate from {@link #serverInit}.
-   */
+  @Override
   public Iterable<Class<? extends OptionsBase>> getStartupOptions() {
     return ImmutableList.of();
   }
@@ -240,37 +239,12 @@ public OutputService getOutputService() throws AbruptExitException {
     return null;
   }
 
-  /**
-   * Returns extra options this module contributes to a specific command. Note that option
-   * inheritance applies: if this method returns a non-empty list, then the returned options are
-   * added to every command that depends on this command.
-   *
-   * <p>This method may be called at any time, and the returned value may be cached. Implementations
-   * must be thread-safe and never return different lists for the same command name. Typical
-   * implementations look like this:
-   *
-   * <pre>
-   * return commandName.equals("build")
-   *     ? ImmutableList.<Class<? extends OptionsBase>>of(MyOptions.class)
-   *     : ImmutableList.<Class<? extends OptionsBase>>of();
-   * </pre>
-   *
-   * Note that this example adds options to all commands that inherit from the build command.
-   *
-   * <p>This method is also used to generate command-line documentation; in order to avoid
-   * duplicated options descriptions, this method should never return the same options class for two
-   * different commands if one of them inherits the other.
-   *
-   * <p>If you want to add options to all commands, override {@link #getCommonCommandOptions}
-   * instead.
-   *
-   * @param commandName the command name, e.g. "build" or "test".
-   */
+  @Override
   public Iterable<Class<? extends OptionsBase>> getCommandOptions(String commandName) {
     return ImmutableList.of();
   }
 
-  /** Returns extra options this module contributes to all commands. */
+  @Override
   public Iterable<Class<? extends OptionsBase>> getCommonCommandOptions() {
     return ImmutableList.of();
   }

src/main/java/com/google/devtools/build/lib/runtime/BlazeOptionHandler.java

@@ -128,7 +128,7 @@ public final class BlazeOptionHandler {
             .flatMap(
                 cmd ->
                     BlazeCommandUtils.getOptions(
-                        cmd, runtime.getBlazeModules(), runtime.getRuleClassProvider())
+                        cmd, runtime.getOptionsSuppliers(), runtime.getRuleClassProvider())
                         .stream())
             .distinct()
             .collect(toImmutableList());