Revert of [Service Manager] Get rid of dynamic service discovery

services/service_manager/public/service_manifest.gni

Index: services/service_manager/public/service_manifest.gni
diff --git a/services/service_manager/public/service_manifest.gni b/services/service_manager/public/service_manifest.gni
index 96eb289959130eb242ded7ec67186a07ef2f42c0..70a8d50bccbd1a9621bf579c77a804d9a6982f89 100644
--- a/services/service_manager/public/service_manifest.gni
+++ b/services/service_manager/public/service_manifest.gni
@@ -3,91 +3,202 @@
 # found in the LICENSE file.
 
 import("//build/config/dcheck_always_on.gni")
+import("//services/service_manager/public/constants.gni")
 
 # Used to produce a Service Manifest for a Service.
 #
-# Service manifests may be subsequently aggregated into one or more catalog
-# manifests (see //services/catalog/public/tools/catalog.gni). A catalog
-# manifest provides the Service Manager at runtime with a static service layout
-# configuration to dictate which services are supported by the runtime
-# environment as well as how individual services may be launched and
-# interconnected.
-#
-# Note that this target may be used to produce partial manifests, and partial
-# manifests may be aggregated by using one service_manifest target as the
-# |source_manifest| of another (see below.)
-#
 # Parameters:
 #
-#   source (optional**)
-#       The manifest template for this service. Must be the name of a valid JSON
-#       file.
-#
-#   source_manifest (optional**)
-#       The manifest template for this service. Must be the name of another
-#       service_manifest target.
-#
-#       ** NOTE: Either |source| OR |source_manifest| MUST be specified.
-#
-#   name (optional)
-#       The name of the service whose manifest is to be generated. A script
-#       validates that the value of this parameter matches the name set in the
-#       source manifest and raises an error if it does not match.
+#   source
+#       The manifest file template for this service, must be valid JSON with
+#       a valid 'url' key matching name.
 #
 #   overlays (optional)
-#       A list of other manifest targets whose outputs should be overlayed onto
-#       the source manifest before emitting the final output. Overlays are
-#       applied in-order as the last step of output generation, after any
-#       |packaged_services| manifests are embedded.
+#       A list of partial manifests to overlay onto the source manifest before
+#       emitting the final output. Overlays are applied as the last step, after
+#       any packaged manifests are embedded.
+#
+#   name
+#       The host portion of the mojo: URL of the service. A script validates
+#       that the value of this parameter matches the host name portion of the
+#       'url' property set in the manifest and throws a ValueError if they do
+#       not.
+#
+#   output_name (optional)
+#       The name of the package to output. The default value is copied from
+#       |name|. Note that this has no effect on the contents of the manifest,
+#       but only determines the output subdirectory within ${out}/Packages.
+#
+#   deps (optional)
+#       An array of dependent instances of this template. This template enforces
+#       that dependencies can only be instances of this template.
 #
 #   packaged_services (optional)
-#       A list of other manifest targets whose outputs should be packaged
-#       within this output manifest, specifically within a toplevel "services"
-#       list.
+#       An array of names of the dependent services.
 #
 # Outputs:
 #
-#   An instantiation of this template produces a meta manifest from the source
-#   template and the output manifests of all its |overlay| and
-#   |packaged_services|dependencies. The output file is always
-#   "$target_gen_dir/${target_name}.json".
+#   An instantiation of this template produces in
+#       $outdir/<name>/manifest.json
+#   a meta manifest from the source template and the output manifest of all
+#   dependent children.
 #
 template("service_manifest") {
-  assert(
-      defined(invoker.source) || defined(invoker.source_manifest),
-      "\"source\" or \"source_manifest\" must be defined for the $target_name target")
-  assert(
-      !defined(invoker.source) || !defined(invoker.source_manifest),
-      "Only one of \"source\" or \"source_manifest\" must be defined for the $target_name target")
+  assert(defined(invoker.source),
+         "\"source\" must be defined for the $target_name template")
+  assert(defined(invoker.name),
+         "\"name\" must be defined for the $target_name template")
+  if (defined(invoker.deps)) {
+    assert(defined(invoker.packaged_services) || defined(invoker.overlays),
+           "\"deps\" implies that you also want \"packaged_services\" and/or" +
+               "\"overlays\", but you have neither.")
+  }
+  if (defined(invoker.packaged_services)) {
+    assert(defined(invoker.deps),
+           "\"deps\" building the dependent packaged services must be " +
+               "provided.")
+  }
 
   action(target_name) {
     script =
         "//services/service_manager/public/tools/manifest/manifest_collator.py"
 
-    deps = []
+    name = invoker.name
+    inputs = [
+      invoker.source,
+    ]
+    if (defined(invoker.overlays)) {
+      inputs += invoker.overlays
+    }
+
+    if (defined(invoker.output_name)) {
+      output = "$root_out_dir/$packages_directory/${invoker.output_name}/manifest.json"
+    } else {
+      output = "$root_out_dir/$packages_directory/$name/manifest.json"
+    }
+    outputs = [
+      output,
+    ]
+
+    rebase_parent = rebase_path(invoker.source, root_build_dir)
+    rebase_output = rebase_path(output, root_build_dir)
+
+    args = [
+      "--name=$name",
+      "--parent=$rebase_parent",
+      "--output=$rebase_output",
+    ]
+
+    if (is_debug || dcheck_always_on) {
+      args += [ "--pretty" ]
+    }
+
+    if (defined(invoker.overlays)) {
+      args += [ "--overlays" ]
+      foreach(overlay_path, invoker.overlays) {
+        args += [ rebase_path(overlay_path, root_build_dir) ]
+      }
+    }
+
+    if (defined(invoker.packaged_services)) {
+      args += [ "--packaged-services" ]
+      foreach(name, invoker.packaged_services) {
+        input = "$root_out_dir/$packages_directory/$name/manifest.json"
+        inputs += [ input ]
+        args += [ rebase_path(input, root_build_dir) ]
+      }
+    }
+    deps = []
+    data_deps = []
     if (defined(invoker.deps)) {
       deps += invoker.deps
-    }
-
-    if (defined(invoker.source)) {
-      source = invoker.source
-    } else {
-      source_target_dir =
-          get_label_info(invoker.source_manifest, "target_gen_dir")
-      source_target_name = get_label_info(invoker.source_manifest, "name")
-      source = "$source_target_dir/${source_target_name}.json"
-      deps += [ invoker.source_manifest ]
-    }
+      data_deps += invoker.deps
+    }
+  }
+
+  all_deps = []
+  if (defined(invoker.deps)) {
+    all_deps += invoker.deps
+  }
+
+  group("${target_name}__is_service_manifest_or_overlay") {
+  }
+
+  # Explicitly ensure that all dependencies are service_manifest
+  # or service_manifest_overlay targets themselves.
+  group("${target_name}__check_deps_are_all_service_manifest") {
+    deps = []
+    foreach(d, all_deps) {
+      name = get_label_info(d, "label_no_toolchain")
+      toolchain = get_label_info(d, "toolchain")
+      deps += [ "${name}__is_service_manifest_or_overlay(${toolchain})" ]
+    }
+  }
+}
+
+# A simple derivative of the service_manifest template above. This allows for
+# embedding of packaged services into a manifest overlay.
+#
+# Parameters:
+#
+#   source
+#       The manifest overlay file to procss.
+#
+#   overlays (optional)
+#       A list of partial manifests to overlay onto the source manifest before
+#       emitting the final output. Overlays are applied as the last step, after
+#       any packaged manifests are embedded.
+#
+#   output_name (optional)
+#       The output name of the manifest. Defaults to the target name.
+#
+#   deps (optional)
+#       An array of the service_manifest targets this overlay depends on.
+#
+#   packaged_services (optional)
+#       An array of names of the services packaged into this overlay.
+#
+# Outputs:
+#
+#   An instantiation of this template produces in
+#       ${root_gen_dir}/${output_name}.json
+#
+template("service_manifest_overlay") {
+  assert(defined(invoker.source),
+         "\"source\" must be defined for the $target_name template")
+  if (defined(invoker.deps)) {
+    assert(defined(invoker.packaged_services) || defined(invoker.overlays),
+           "\"deps\" implies that you also want \"packaged_services\" and/or" +
+               "\"overlays\", but you have neither.")
+  }
+  if (defined(invoker.packaged_services)) {
+    assert(defined(invoker.deps),
+           "\"deps\" building the dependent packaged services must be " +
+               "provided.")
+  }
+
+  action(target_name) {
+    script =
+        "//services/service_manager/public/tools/manifest/manifest_collator.py"
+
     inputs = [
-      source,
-    ]
-
-    output = "$target_gen_dir/${target_name}.json"
+      invoker.source,
+    ]
+    if (defined(invoker.overlays)) {
+      inputs += invoker.overlays
+    }
+
+    output_name = target_name
+    if (defined(invoker.output_name)) {
+      output_name = invoker.output_name
+    }
+    output = "${root_gen_dir}/${output_name}.json"
+
     outputs = [
       output,
     ]
 
-    rebase_parent = rebase_path(source, root_build_dir)
+    rebase_parent = rebase_path(invoker.source, root_build_dir)
     rebase_output = rebase_path(output, root_build_dir)
 
     args = [
@@ -95,56 +206,45 @@
       "--output=$rebase_output",
     ]
 
-    if (defined(invoker.name)) {
-      args += [
-        "--name",
-        invoker.name,
-      ]
-    }
-
     if (is_debug || dcheck_always_on) {
       args += [ "--pretty" ]
     }
 
     if (defined(invoker.overlays)) {
       args += [ "--overlays" ]
-      foreach(manifest_target, invoker.overlays) {
-        manifest_target_dir = get_label_info(manifest_target, "target_gen_dir")
-        manifest_target_name = get_label_info(manifest_target, "name")
-        manifest_filename = "$manifest_target_dir/${manifest_target_name}.json"
-
-        inputs += [ manifest_filename ]
-        deps += [ manifest_target ]
-        args += [ rebase_path(manifest_filename, root_build_dir) ]
-
-        # Ensure that each entry does in fact reference a manifest rule.
-        label_no_toolchain =
-            get_label_info(manifest_target, "label_no_toolchain")
-        toolchain = get_label_info(manifest_target, "toolchain")
-        deps += [ "${label_no_toolchain}__is_service_manifest(${toolchain})" ]
+      foreach(overlay_path, invoker.overlays) {
+        args += [ rebase_path(overlay_path, root_build_dir) ]
       }
     }
 
     if (defined(invoker.packaged_services)) {
       args += [ "--packaged-services" ]
-      foreach(manifest_target, invoker.packaged_services) {
-        manifest_target_dir = get_label_info(manifest_target, "target_gen_dir")
-        manifest_target_name = get_label_info(manifest_target, "name")
-        manifest_filename = "$manifest_target_dir/${manifest_target_name}.json"
-
-        inputs += [ manifest_filename ]
-        deps += [ manifest_target ]
-        args += [ rebase_path(manifest_filename, root_build_dir) ]
-
-        # Ensure that each entry does in fact reference a manifest rule.
-        label_no_toolchain =
-            get_label_info(manifest_target, "label_no_toolchain")
-        toolchain = get_label_info(manifest_target, "toolchain")
-        deps += [ "${label_no_toolchain}__is_service_manifest(${toolchain})" ]
-      }
-    }
-  }
-
-  group("${target_name}__is_service_manifest") {
+      foreach(name, invoker.packaged_services) {
+        input = "$root_out_dir/$packages_directory/$name/manifest.json"
+        inputs += [ input ]
+        args += [ rebase_path(input, root_build_dir) ]
+      }
+    }
+
+    deps = []
+    data_deps = []
+    if (defined(invoker.deps)) {
+      deps += invoker.deps
+      data_deps += invoker.deps
+    }
+  }
+
+  group("${target_name}__is_service_manifest_or_overlay") {
+  }
+
+  # Explicitly ensure that all dependencies are service_manifest
+  # or service_manifest_overlay targets themselves.
+  group("${target_name}__check_deps_are_all_service_manifest") {
+    deps = []
+    foreach(d, all_deps) {
+      name = get_label_info(d, "label_no_toolchain")
+      toolchain = get_label_info(d, "toolchain")
+      deps += [ "${name}__is_service_manifest_or_overlay(${toolchain})" ]
+    }
   }
 }