config/lib/ci_yaml/ci_yaml.star - infra - Git at Google

 #!/usr/bin/env lucicfg
 # Copyright 2020 The Flutter Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 """
 Utility for loading Flutter infrastructure's yaml config into LUCI.

 See https://github.com/flutter/cocoon/blob/main/CI_YAML.md for more information.
 """

 proto.new_descriptor_set(
     name = "scheduler",
     blob = io.read_file("./scheduler.bin"),
 ).register()

 load("@proto//scheduler.proto", _scheduler_pb = "scheduler")
 load("//lib/common.star", "common")
 load("//lib/copy.star", "copy")
 load("//lib/helpers.star", "helpers")
 load("//lib/repos.star", "repos")

 def _ci_yaml(repo, branch):
     """Creates ci_yaml object.

     ci_yamls are expected to have a generated jspb file under
     //config/generated/ci_yaml with the format `$repo_config.json` for tip of
     tree or `$repo_$branch_config.json` for release branches.

     ci_yaml json files are autogenerated based on the .ci.yaml in $repo.

     Args:
         repo(str): Name of the repository to follow.
         branch(str): Branch name.
     """
     version = "" if _is_default_branch(branch) else "_%s" % branch
     return proto.from_jsonpb(
         _scheduler_pb.SchedulerConfig,
         io.read_file("./generated/ci_yaml/%s%s_config.json" % (repo, version)),
     )

 # lucicfg does not currently support enums from protos.
 # To work around this, statically redeclare the values from:
 #   //config/lib/ci_yaml/scheduler.proto - SchedulerSytem
 SCHEDULER_COCOON = 1
 SCHEDULER_LUCI = 2

 # lucicfg is only intended to generate LUCI based targets.
 SUPPORTED_SCHEDULERS = [SCHEDULER_COCOON, SCHEDULER_LUCI]

 def _recipes(repo, branch, recipes_ref):
     """Return the set of recipes specified in ci.yaml."""
     recipe_names = {}
     ci_yaml = _ci_yaml(repo, branch)
     for target in ci_yaml.targets:
         # Only LUCI based targets have recipes
         if target.scheduler not in SUPPORTED_SCHEDULERS:
             continue
         if target.enabled_branches and branch not in target.enabled_branches:
             continue
         recipe_name = _full_recipe_name(target.recipe, recipes_ref)
         if recipe_name not in recipe_names.keys():
             recipe_names[recipe_name] = target.recipe
     for recipe_name, recipe in recipe_names.items():
         luci.recipe(
             name = recipe_name,
             recipe = recipe,
             cipd_package = "flutter/recipe_bundles/flutter.googlesource.com/recipes",
             cipd_version = recipes_ref,
             use_bbagent = True,
         )

 def _add_recipes_cq(target):
     if "add_recipes_cq" in target.properties:
         return target.properties["add_recipes_cq"] == "true"
     return False

 def _swarming_caches(repo, version, dependencies = [], ios_runtimes = [], xcode = None):
     """Return the equivalent swarming caches for target.

     Caches are generated based on a targets dependencies, the version, and their branch.
     """
     if version == None:
         version = "main"
     legacy_paths = {
         "android_sdk": "android",
         "chrome_and_driver": "chrome",
         "open_jdk": "java",
     }
     swarming_caches = [
         swarming.cache(path = "builder", name = repo + "_" + version + "_builder"),
         swarming.cache(path = ".pub-cache", name = "pub_cache"),
     ]
     for dependency in dependencies:
         path = dependency["dependency"]
         if path == "xcode":
             continue
         dep_version = dependency["version"] if "version" in dependency else "default"
         name = repo + "_" + version + "_" + path + "_" + dep_version
         name = name.replace(":", "_")
         name = name.replace("-", "_")
         name = name.replace(".", "_")
         swarming_caches.append(swarming.cache(name = name, path = path))
         if path in legacy_paths:
             swarming_caches.append(swarming.cache(name = name + "_legacy", path = legacy_paths[path]))
     for runtime in ios_runtimes:
         path = "xcode_runtime_" + runtime
         path = path.replace("-", "_")
         name = repo + "_" + version + "_" + path
         swarming_caches.append(swarming.cache(name = name, path = path))
     if xcode:
         name = repo + "_" + version + "_xcode_" + xcode
         swarming_caches.append(swarming.cache(name = name + "_legacy", path = "osx_sdk"))
         swarming_caches.append(swarming.cache(name = name, path = "xcode"))
     return swarming_caches

 def _legacy_swarming_caches(ci_yaml, target, platform):
     """DEPRECATED: Return the swarming caches based on what is listed in ci.yaml."""
     swarming_caches = []
     caches = []
     cache_set = []

     # Target specific caches
     if target and "caches" in target.properties:
         caches = json.decode(target.properties["caches"])

         # Mark all in unique set to ensure platform does not override
         for cache in caches:
             cache_set.append(cache["name"])

     # Platform wide caches
     if "caches" in ci_yaml.platform_properties[platform].properties:
         platform_caches = json.decode(ci_yaml.platform_properties[platform].properties["caches"])

         # Ensure platform wide caches do not override target level caches
         for platform_cache in platform_caches:
             if platform_cache["name"] not in cache_set:
                 caches.append(platform_cache)

     # Generate LUCI config caches
     for cache in caches:
         swarming_caches.append(swarming.cache(name = cache["name"], path = cache["path"]))
     return swarming_caches

 def _platform_dimensions(ci_yaml):
     """Gets platform_dimensions from ci_yaml."""
     platform_dimensions = {}
     for platform, _ in dict(ci_yaml.platform_properties).items():
         platform_dimensions[platform] = {}
         for k, v in dict(ci_yaml.platform_properties[platform].dimensions).items():
             platform_dimensions[platform][k] = _parse_attribute(k, v)
     return platform_dimensions

 def _platform_properties(ci_yaml):
     """Gets platform_properties from ci_yaml."""
     platform_properties = {}
     for platform, _ in dict(ci_yaml.platform_properties).items():
         platform_properties[platform] = {}
         for k, v in dict(ci_yaml.platform_properties[platform].properties).items():
             platform_properties[platform][k] = _parse_attribute(k, v)
     return platform_properties

 def _parse_attribute(key, value):
     """Helper function to parse non string type properties."""
     json_list = ["android_sdk_license", "android_sdk_preview_license"]
     if value == "true":
         return True
     elif value == "false":
         return False
     elif key in json_list:
         # Yaml -> JSON -> Here adds an extra string escape that we unescape here
         return value.replace("\\n", "\n")
     elif value.startswith("["):
         return json.decode(value)
     elif value.isdigit():
         return int(value)
     else:
         return value

 def _dimensions(ci_yaml, target):
     dimensions = {}

     # Update with platform specific dimensions
     platform = _target_platform(target)
     input_platform_dimensions = _platform_dimensions(ci_yaml)
     if platform in input_platform_dimensions:
         for k, v in input_platform_dimensions[platform].items():
             dimensions[k] = v

     # Update with target specific dimensions
     for k, v in dict(target.dimensions).items():
         dimensions[k] = _parse_attribute(k, v)
     return dimensions

 def _properties(ci_yaml, target, default_properties = {}, repo = None, branch = None):
     """Creates builder properties based on ci_yaml.

     Args:
         ci_yaml(SchedulerConfig): Config file that contains target.
         target(Target): Configuration to generate properties for.
         default_properties(dict): Repo level properties.
         repo(string): Name of the repo.
         branch(string): Name of the branch.
     """
     properties = {}

     # Initialize with default repo properties
     for k, v in default_properties.items():
         properties[k] = v

     # Update with platform specific properties
     platform = _target_platform(target)
     input_platform_properties = _platform_properties(ci_yaml)
     if platform in input_platform_properties:
         for k, v in input_platform_properties[platform].items():
             properties[k] = v

     # Finally, update with target specific properties
     for k, v in dict(target.properties).items():
         if k == "dependencies":
             # Merge target dependencies with platform
             dependencies = json.decode(v)
             target_dependency_lookup_table = []
             for dep in dependencies:
                 target_dependency_lookup_table.append(dep["dependency"])

             # Add platform dependencies that are not already defined
             for dep in properties[k]:
                 if dep["dependency"] not in target_dependency_lookup_table:
                     dependencies.append(dep)
             properties[k] = dependencies
         else:
             properties[k] = _parse_attribute(k, v)

     # Special case to pass xcode for engine
     for xcode_platform in ["mac", "mac_ios", "mac_arm64_ios"]:
         if platform != xcode_platform:
             continue
         if "xcode" not in properties:
             continue
         xcode_version = {
             "sdk_version": properties["xcode"],
         }

         # DeviceLab bots are on a slower lab network. We avoid LUCI caches on those bots
         if platform in ["mac_ios", "mac_arm64_ios"]:
             properties["$flutter/devicelab_osx_sdk"] = xcode_version
         else:
             properties["$flutter/osx_sdk"] = xcode_version

     # Special case to add runtimes for ios simultators
     if platform == "mac" and "runtime_versions" in properties:
         # Add to existing osx_sdk properties dict, or create new
         osx_sdk = properties.get("$flutter/osx_sdk", {})
         osx_sdk["runtime_versions"] = properties["runtime_versions"]
         properties["$flutter/osx_sdk"] = osx_sdk

     filter_list = ["caches"]
     for filter in filter_list:
         if filter in properties:
             properties.pop(filter)
     if repo:
         properties["git_repo"] = repo
     if branch:
         properties["git_branch"] = branch

     # Add `bringup` to properties.
     properties["bringup"] = target.bringup

     if "dependencies" not in properties:
         properties["dependencies"] = []
     return properties

 def _full_recipe_name(recipe_name, recipes_ref):
     """Creates a recipe name for recipe and version.

     Args:
       recipe_name(str): This is a string with the recipe base name.
       recipes_ref(str): The git ref pointing to the recipes bundle to use.

     Returns:
       A string with the recipe's full name.
     """
     ref = recipes_ref.replace("refs/heads/", "")
     return "%s-%s" % (ref, recipe_name)

 def _builder_name(builder_name, branch):
     """Creates a builder name that is versioned to branch.

     Args:
         builder_name(str): The original builder name.
         branch(str): Branch this builder is for.
     """
     if not _is_default_branch(branch):
         parts = builder_name.split(" ")
         parts.insert(1, branch)
         builder_name = " ".join(parts)
     return "%s|%s" % (builder_name, common.short_name(builder_name))

 def _is_default_branch(branch):
     """Returns whether the branch is a default branch."""
     return branch in ("main", "master")

 def _builders(repo, branch, version, testing_ref, dimensions, properties, triggering_policy, notifies = None, recipes_ref = "refs/heads/main"):
     """Return the builders specified in ci.yaml.

     Targets defined in .ci.yaml are translated to their LUCI equivalents.
     Mostly, this is forward fields to the LUCI equivalent, but there
     are some fields that are special cased.

     Args:
         repo(str): Name of the repo to create builders for.
         branch(str): Name of the branch to create builders for. Either None:dev|beta|stable.
         version(str): The branch number, following major_minor.
         testing_ref(str): The git ref to trigger builds on.
         dimensions(dict): Platform dimensions to pass.
         properties(dict): Repo level properties to pass to every builder.
         triggering_policy(scheduler): Scheduler policy to implement on postsubmit builds.
         notifies(list): List of luci.notifier to send notifications on events from builders.
         recipes_ref(str): The git ref pointing to the recipes bundle to use.
     """
     ci_yaml = _ci_yaml(repo, branch)

     # Only generate presubmit and staging builds on tip of tree
     staging_view_name = "%s_staging" % repo
     if _is_default_branch(branch):
         list_view_name = "%s-try" % repo
         luci.list_view(
             name = list_view_name,
             title = "%s try builders" % repo.capitalize(),
         )
         luci.console_view(
             name = staging_view_name,
             repo = repos.GIT_REMOTE[repo],
             refs = [testing_ref],
         )
     console_view_name = repo if _is_default_branch(branch) else "%s_%s" % (branch, repo)
     luci.console_view(
         name = console_view_name,
         repo = repos.GIT_REMOTE[repo],
         refs = [testing_ref],
     )

     # Defines prod schedulers
     trigger_name = "%s-gitiles-trigger-%s" % (branch, repo)
     luci.gitiles_poller(
         name = trigger_name,
         bucket = "prod",
         repo = repos.GIT_REMOTE[repo],
         refs = [testing_ref],
     )

     # Defines default triggering policy
     if not triggering_policy:
         triggering_policy = scheduler.greedy_batching(
             max_batch_size = 1,
             max_concurrent_invocations = 3,
         )

     for target in ci_yaml.targets:
         # Not all targets in ci.yaml are LUCI based, skip those.
         if target.scheduler not in SUPPORTED_SCHEDULERS:
             continue

         # Flaky tests should not be on releases
         if not _is_default_branch(branch) and target.bringup:
             continue
         platform = _target_platform(target)
         merged_dimensions = _dimensions(ci_yaml, target)
         merged_properties = _properties(ci_yaml, target, properties, repo, branch)
         ios_simulators = []
         if "runtime_versions" in merged_properties:
             ios_simulators = merged_properties["runtime_versions"]
         xcode = merged_properties["xcode"] if "xcode" in merged_properties else None
         caches = _swarming_caches(repo, version, merged_properties["dependencies"], ios_simulators, xcode)
         target_args = {
             "caches": caches,
             "dimensions": merged_dimensions,
             # On release branches, extend the timeout to handle goma misses.
             # TODO(godofredoc): Remove after hotfix 2.5.3 is released.
             "execution_timeout": target.timeout * time.minute * 3,
             "name": _builder_name(target.name, branch),
             "os": merged_properties["os"],
             "recipe": _full_recipe_name(target.recipe, recipes_ref),
             "repo": repos.GIT_REMOTE[repo],
             "properties": merged_properties,
         }

         # Set dimensions dimensions from properties.
         if platform in dimensions:
             target_args["dimensions"] = dimensions[platform]
         dimension_key_list = ("device_type", "device_os", "mac_model", "cores", "cpu")
         for dimension_key in dimension_key_list:
             if dimension_key in merged_properties:
                 target_args["dimensions"][dimension_key] = str(merged_properties[dimension_key])

         # Try builds are generated for every target to enable led and presubmit runs
         if _is_default_branch(branch):
             presubmit_target_args = copy.deepcopy(target_args)
             presubmit_target_args["list_view_name"] = list_view_name
             if repo == "engine":
                 presubmit_target_args["properties"]["no_lto"] = True
             if _add_recipes_cq(target):
                 presubmit_target_args["add_cq"] = True
             common.common_try_builder(**presubmit_target_args)

         postsubmit_target_args = helpers.merge_dicts({
             "priority": 30,
             "notifies": notifies,
             "category": platform.capitalize(),
         }, target_args)

         # Postsubmit only generates if the target is enabled for this branch, which defaults to true.
         if not target.enabled_branches or branch in target.enabled_branches:
             # Set customized triggering policy for engine staging builders.
             # https://github.com/flutter/flutter/issues/92947
             if target.bringup:
                 final_triggering_policy = scheduler.greedy_batching(
                     max_batch_size = 6,
                     max_concurrent_invocations = 1,
                 )
             else:
                 final_triggering_policy = triggering_policy

             # Mark triggering policy as none if the target is not scheduled by LUCI
             final_triggering_policy = final_triggering_policy if target.scheduler == SCHEDULER_LUCI else None

             # TODO(chillers): Remove when postsubmit properties are supported. https://github.com/flutter/flutter/issues/87675
             if target.recipe == "devicelab/devicelab_drone":
                 if _is_default_branch(branch):
                     postsubmit_target_args["properties"]["upload_metrics"] = True

                     # Set a 2h expiration_timeout for non flaky devicelab builders.
                     if not target.bringup:
                         postsubmit_target_args["expiration_timeout"] = 120 * time.minute
             staging_target_args = helpers.merge_dicts({
                 "bucket": "staging",
                 "console_view_name": staging_view_name,
                 "expiration_timeout": 24 * time.hour,
                 "pool": "luci.flutter.staging",
             }, postsubmit_target_args)
             prod_target_args = helpers.merge_dicts({
                 "bucket": "prod",
                 "console_view_name": console_view_name,
                 "pool": "luci.flutter.prod",
             }, postsubmit_target_args)

             # Only trigger targets in a single bucket based on bringup
             if target.bringup:
                 staging_target_args["triggered_by"] = [trigger_name] if target.scheduler == SCHEDULER_LUCI else None
                 staging_target_args["triggering_policy"] = final_triggering_policy
             else:
                 prod_target_args["triggered_by"] = [trigger_name] if target.scheduler == SCHEDULER_LUCI else None
                 prod_target_args["triggering_policy"] = final_triggering_policy

             # Both staging and prod builders are generated to retain information and make it easy to swap
             common.common_prod_builder(**prod_target_args)
             common.common_prod_builder(**staging_target_args)

 def _target_platform(target):
     """Return the target platform based on the name."""
     platform = target.name.split(" ")[0]
     return platform.lower()

 def _generate(repo, branch, version, testing_ref, dimensions = {}, properties = {}, triggering_policy = None, notifies = None, recipes_ref = "refs/heads/main"):
     # CQ group configurations. Only FLUTTER_RECIPES is using
     # LUCI CQ but we still need the CQ configurations for all
     # the try configurations for led recipe tests.
     if _is_default_branch(branch):
         common.cq_group(repos.GIT_REMOTE[repo])
     _recipes(repo, branch, recipes_ref)
     _builders(repo, branch, version, testing_ref, dimensions, properties, triggering_policy, notifies = notifies, recipes_ref = recipes_ref)

 ci_yaml = struct(
     builder_name = _builder_name,
     ci_yaml = _ci_yaml,
     full_recipe_name = _full_recipe_name,
     generate = _generate,
     legacy_swarming_caches = _legacy_swarming_caches,
     platform_properties = _platform_properties,
     properties = _properties,
     swarming_caches = _swarming_caches,
 )
	#!/usr/bin/env lucicfg
	# Copyright 2020 The Flutter Authors. All rights reserved.
	# Use of this source code is governed by a BSD-style license that can be
	# found in the LICENSE file.
	"""
	Utility for loading Flutter infrastructure's yaml config into LUCI.

	See https://github.com/flutter/cocoon/blob/main/CI_YAML.md for more information.
	"""

	proto.new_descriptor_set(
	name = "scheduler",
	blob = io.read_file("./scheduler.bin"),
	).register()

	load("@proto//scheduler.proto", _scheduler_pb = "scheduler")
	load("//lib/common.star", "common")
	load("//lib/copy.star", "copy")
	load("//lib/helpers.star", "helpers")
	load("//lib/repos.star", "repos")

	def _ci_yaml(repo, branch):
	"""Creates ci_yaml object.

	ci_yamls are expected to have a generated jspb file under
	//config/generated/ci_yaml with the format `$repo_config.json` for tip of
	tree or `$repo_$branch_config.json` for release branches.

	ci_yaml json files are autogenerated based on the .ci.yaml in $repo.

	Args:
	repo(str): Name of the repository to follow.
	branch(str): Branch name.
	"""
	version = "" if _is_default_branch(branch) else "_%s" % branch
	return proto.from_jsonpb(
	_scheduler_pb.SchedulerConfig,
	io.read_file("./generated/ci_yaml/%s%s_config.json" % (repo, version)),
	)

	# lucicfg does not currently support enums from protos.
	# To work around this, statically redeclare the values from:
	# //config/lib/ci_yaml/scheduler.proto - SchedulerSytem
	SCHEDULER_COCOON = 1
	SCHEDULER_LUCI = 2

	# lucicfg is only intended to generate LUCI based targets.
	SUPPORTED_SCHEDULERS = [SCHEDULER_COCOON, SCHEDULER_LUCI]

	def _recipes(repo, branch, recipes_ref):
	"""Return the set of recipes specified in ci.yaml."""
	recipe_names = {}
	ci_yaml = _ci_yaml(repo, branch)
	for target in ci_yaml.targets:
	# Only LUCI based targets have recipes
	if target.scheduler not in SUPPORTED_SCHEDULERS:
	continue
	if target.enabled_branches and branch not in target.enabled_branches:
	continue
	recipe_name = _full_recipe_name(target.recipe, recipes_ref)
	if recipe_name not in recipe_names.keys():
	recipe_names[recipe_name] = target.recipe
	for recipe_name, recipe in recipe_names.items():
	luci.recipe(
	name = recipe_name,
	recipe = recipe,
	cipd_package = "flutter/recipe_bundles/flutter.googlesource.com/recipes",
	cipd_version = recipes_ref,
	use_bbagent = True,
	)

	def _add_recipes_cq(target):
	if "add_recipes_cq" in target.properties:
	return target.properties["add_recipes_cq"] == "true"
	return False

	def _swarming_caches(repo, version, dependencies = [], ios_runtimes = [], xcode = None):
	"""Return the equivalent swarming caches for target.

	Caches are generated based on a targets dependencies, the version, and their branch.
	"""
	if version == None:
	version = "main"
	legacy_paths = {
	"android_sdk": "android",
	"chrome_and_driver": "chrome",
	"open_jdk": "java",
	}
	swarming_caches = [
	swarming.cache(path = "builder", name = repo + "_" + version + "_builder"),
	swarming.cache(path = ".pub-cache", name = "pub_cache"),
	]
	for dependency in dependencies:
	path = dependency["dependency"]
	if path == "xcode":
	continue
	dep_version = dependency["version"] if "version" in dependency else "default"
	name = repo + "_" + version + "_" + path + "_" + dep_version
	name = name.replace(":", "_")
	name = name.replace("-", "_")
	name = name.replace(".", "_")
	swarming_caches.append(swarming.cache(name = name, path = path))
	if path in legacy_paths:
	swarming_caches.append(swarming.cache(name = name + "_legacy", path = legacy_paths[path]))
	for runtime in ios_runtimes:
	path = "xcode_runtime_" + runtime
	path = path.replace("-", "_")
	name = repo + "_" + version + "_" + path
	swarming_caches.append(swarming.cache(name = name, path = path))
	if xcode:
	name = repo + "_" + version + "_xcode_" + xcode
	swarming_caches.append(swarming.cache(name = name + "_legacy", path = "osx_sdk"))
	swarming_caches.append(swarming.cache(name = name, path = "xcode"))
	return swarming_caches

	def _legacy_swarming_caches(ci_yaml, target, platform):
	"""DEPRECATED: Return the swarming caches based on what is listed in ci.yaml."""
	swarming_caches = []
	caches = []
	cache_set = []

	# Target specific caches
	if target and "caches" in target.properties:
	caches = json.decode(target.properties["caches"])

	# Mark all in unique set to ensure platform does not override
	for cache in caches:
	cache_set.append(cache["name"])

	# Platform wide caches
	if "caches" in ci_yaml.platform_properties[platform].properties:
	platform_caches = json.decode(ci_yaml.platform_properties[platform].properties["caches"])

	# Ensure platform wide caches do not override target level caches
	for platform_cache in platform_caches:
	if platform_cache["name"] not in cache_set:
	caches.append(platform_cache)

	# Generate LUCI config caches
	for cache in caches:
	swarming_caches.append(swarming.cache(name = cache["name"], path = cache["path"]))
	return swarming_caches

	def _platform_dimensions(ci_yaml):
	"""Gets platform_dimensions from ci_yaml."""
	platform_dimensions = {}
	for platform, _ in dict(ci_yaml.platform_properties).items():
	platform_dimensions[platform] = {}
	for k, v in dict(ci_yaml.platform_properties[platform].dimensions).items():
	platform_dimensions[platform][k] = _parse_attribute(k, v)
	return platform_dimensions

	def _platform_properties(ci_yaml):
	"""Gets platform_properties from ci_yaml."""
	platform_properties = {}
	for platform, _ in dict(ci_yaml.platform_properties).items():
	platform_properties[platform] = {}
	for k, v in dict(ci_yaml.platform_properties[platform].properties).items():
	platform_properties[platform][k] = _parse_attribute(k, v)
	return platform_properties

	def _parse_attribute(key, value):
	"""Helper function to parse non string type properties."""
	json_list = ["android_sdk_license", "android_sdk_preview_license"]
	if value == "true":
	return True
	elif value == "false":
	return False
	elif key in json_list:
	# Yaml -> JSON -> Here adds an extra string escape that we unescape here
	return value.replace("\\n", "\n")
	elif value.startswith("["):
	return json.decode(value)
	elif value.isdigit():
	return int(value)
	else:
	return value

	def _dimensions(ci_yaml, target):
	dimensions = {}

	# Update with platform specific dimensions
	platform = _target_platform(target)
	input_platform_dimensions = _platform_dimensions(ci_yaml)
	if platform in input_platform_dimensions:
	for k, v in input_platform_dimensions[platform].items():
	dimensions[k] = v

	# Update with target specific dimensions
	for k, v in dict(target.dimensions).items():
	dimensions[k] = _parse_attribute(k, v)
	return dimensions

	def _properties(ci_yaml, target, default_properties = {}, repo = None, branch = None):
	"""Creates builder properties based on ci_yaml.

	Args:
	ci_yaml(SchedulerConfig): Config file that contains target.
	target(Target): Configuration to generate properties for.
	default_properties(dict): Repo level properties.
	repo(string): Name of the repo.
	branch(string): Name of the branch.
	"""
	properties = {}

	# Initialize with default repo properties
	for k, v in default_properties.items():
	properties[k] = v

	# Update with platform specific properties
	platform = _target_platform(target)
	input_platform_properties = _platform_properties(ci_yaml)
	if platform in input_platform_properties:
	for k, v in input_platform_properties[platform].items():
	properties[k] = v

	# Finally, update with target specific properties
	for k, v in dict(target.properties).items():
	if k == "dependencies":
	# Merge target dependencies with platform
	dependencies = json.decode(v)
	target_dependency_lookup_table = []
	for dep in dependencies:
	target_dependency_lookup_table.append(dep["dependency"])

	# Add platform dependencies that are not already defined
	for dep in properties[k]:
	if dep["dependency"] not in target_dependency_lookup_table:
	dependencies.append(dep)
	properties[k] = dependencies
	else:
	properties[k] = _parse_attribute(k, v)

	# Special case to pass xcode for engine
	for xcode_platform in ["mac", "mac_ios", "mac_arm64_ios"]:
	if platform != xcode_platform:
	continue
	if "xcode" not in properties:
	continue
	xcode_version = {
	"sdk_version": properties["xcode"],
	}

	# DeviceLab bots are on a slower lab network. We avoid LUCI caches on those bots
	if platform in ["mac_ios", "mac_arm64_ios"]:
	properties["$flutter/devicelab_osx_sdk"] = xcode_version
	else:
	properties["$flutter/osx_sdk"] = xcode_version

	# Special case to add runtimes for ios simultators
	if platform == "mac" and "runtime_versions" in properties:
	# Add to existing osx_sdk properties dict, or create new
	osx_sdk = properties.get("$flutter/osx_sdk", {})
	osx_sdk["runtime_versions"] = properties["runtime_versions"]
	properties["$flutter/osx_sdk"] = osx_sdk

	filter_list = ["caches"]
	for filter in filter_list:
	if filter in properties:
	properties.pop(filter)
	if repo:
	properties["git_repo"] = repo
	if branch:
	properties["git_branch"] = branch

	# Add `bringup` to properties.
	properties["bringup"] = target.bringup

	if "dependencies" not in properties:
	properties["dependencies"] = []
	return properties

	def _full_recipe_name(recipe_name, recipes_ref):
	"""Creates a recipe name for recipe and version.

	Args:
	recipe_name(str): This is a string with the recipe base name.
	recipes_ref(str): The git ref pointing to the recipes bundle to use.

	Returns:
	A string with the recipe's full name.
	"""
	ref = recipes_ref.replace("refs/heads/", "")
	return "%s-%s" % (ref, recipe_name)

	def _builder_name(builder_name, branch):
	"""Creates a builder name that is versioned to branch.

	Args:
	builder_name(str): The original builder name.
	branch(str): Branch this builder is for.
	"""
	if not _is_default_branch(branch):
	parts = builder_name.split(" ")
	parts.insert(1, branch)
	builder_name = " ".join(parts)
	return "%s\|%s" % (builder_name, common.short_name(builder_name))

	def _is_default_branch(branch):
	"""Returns whether the branch is a default branch."""
	return branch in ("main", "master")

	def _builders(repo, branch, version, testing_ref, dimensions, properties, triggering_policy, notifies = None, recipes_ref = "refs/heads/main"):
	"""Return the builders specified in ci.yaml.

	Targets defined in .ci.yaml are translated to their LUCI equivalents.
	Mostly, this is forward fields to the LUCI equivalent, but there
	are some fields that are special cased.

	Args:
	repo(str): Name of the repo to create builders for.
	branch(str): Name of the branch to create builders for. Either None:dev\|beta\|stable.
	version(str): The branch number, following major_minor.
	testing_ref(str): The git ref to trigger builds on.
	dimensions(dict): Platform dimensions to pass.
	properties(dict): Repo level properties to pass to every builder.
	triggering_policy(scheduler): Scheduler policy to implement on postsubmit builds.
	notifies(list): List of luci.notifier to send notifications on events from builders.
	recipes_ref(str): The git ref pointing to the recipes bundle to use.
	"""
	ci_yaml = _ci_yaml(repo, branch)

	# Only generate presubmit and staging builds on tip of tree
	staging_view_name = "%s_staging" % repo
	if _is_default_branch(branch):
	list_view_name = "%s-try" % repo
	luci.list_view(
	name = list_view_name,
	title = "%s try builders" % repo.capitalize(),
	)
	luci.console_view(
	name = staging_view_name,
	repo = repos.GIT_REMOTE[repo],
	refs = [testing_ref],
	)
	console_view_name = repo if _is_default_branch(branch) else "%s_%s" % (branch, repo)
	luci.console_view(
	name = console_view_name,
	repo = repos.GIT_REMOTE[repo],
	refs = [testing_ref],
	)

	# Defines prod schedulers
	trigger_name = "%s-gitiles-trigger-%s" % (branch, repo)
	luci.gitiles_poller(
	name = trigger_name,
	bucket = "prod",
	repo = repos.GIT_REMOTE[repo],
	refs = [testing_ref],
	)

	# Defines default triggering policy
	if not triggering_policy:
	triggering_policy = scheduler.greedy_batching(
	max_batch_size = 1,
	max_concurrent_invocations = 3,
	)

	for target in ci_yaml.targets:
	# Not all targets in ci.yaml are LUCI based, skip those.
	if target.scheduler not in SUPPORTED_SCHEDULERS:
	continue

	# Flaky tests should not be on releases
	if not _is_default_branch(branch) and target.bringup:
	continue
	platform = _target_platform(target)
	merged_dimensions = _dimensions(ci_yaml, target)
	merged_properties = _properties(ci_yaml, target, properties, repo, branch)
	ios_simulators = []
	if "runtime_versions" in merged_properties:
	ios_simulators = merged_properties["runtime_versions"]
	xcode = merged_properties["xcode"] if "xcode" in merged_properties else None
	caches = _swarming_caches(repo, version, merged_properties["dependencies"], ios_simulators, xcode)
	target_args = {
	"caches": caches,
	"dimensions": merged_dimensions,
	# On release branches, extend the timeout to handle goma misses.
	# TODO(godofredoc): Remove after hotfix 2.5.3 is released.
	"execution_timeout": target.timeout * time.minute * 3,
	"name": _builder_name(target.name, branch),
	"os": merged_properties["os"],
	"recipe": _full_recipe_name(target.recipe, recipes_ref),
	"repo": repos.GIT_REMOTE[repo],
	"properties": merged_properties,
	}

	# Set dimensions dimensions from properties.
	if platform in dimensions:
	target_args["dimensions"] = dimensions[platform]
	dimension_key_list = ("device_type", "device_os", "mac_model", "cores", "cpu")
	for dimension_key in dimension_key_list:
	if dimension_key in merged_properties:
	target_args["dimensions"][dimension_key] = str(merged_properties[dimension_key])

	# Try builds are generated for every target to enable led and presubmit runs
	if _is_default_branch(branch):
	presubmit_target_args = copy.deepcopy(target_args)
	presubmit_target_args["list_view_name"] = list_view_name
	if repo == "engine":
	presubmit_target_args["properties"]["no_lto"] = True
	if _add_recipes_cq(target):
	presubmit_target_args["add_cq"] = True
	common.common_try_builder(**presubmit_target_args)

	postsubmit_target_args = helpers.merge_dicts({
	"priority": 30,
	"notifies": notifies,
	"category": platform.capitalize(),
	}, target_args)

	# Postsubmit only generates if the target is enabled for this branch, which defaults to true.
	if not target.enabled_branches or branch in target.enabled_branches:
	# Set customized triggering policy for engine staging builders.
	# https://github.com/flutter/flutter/issues/92947
	if target.bringup:
	final_triggering_policy = scheduler.greedy_batching(
	max_batch_size = 6,
	max_concurrent_invocations = 1,
	)
	else:
	final_triggering_policy = triggering_policy

	# Mark triggering policy as none if the target is not scheduled by LUCI
	final_triggering_policy = final_triggering_policy if target.scheduler == SCHEDULER_LUCI else None

	# TODO(chillers): Remove when postsubmit properties are supported. https://github.com/flutter/flutter/issues/87675
	if target.recipe == "devicelab/devicelab_drone":
	if _is_default_branch(branch):
	postsubmit_target_args["properties"]["upload_metrics"] = True

	# Set a 2h expiration_timeout for non flaky devicelab builders.
	if not target.bringup:
	postsubmit_target_args["expiration_timeout"] = 120 * time.minute
	staging_target_args = helpers.merge_dicts({
	"bucket": "staging",
	"console_view_name": staging_view_name,
	"expiration_timeout": 24 * time.hour,
	"pool": "luci.flutter.staging",
	}, postsubmit_target_args)
	prod_target_args = helpers.merge_dicts({
	"bucket": "prod",
	"console_view_name": console_view_name,
	"pool": "luci.flutter.prod",
	}, postsubmit_target_args)

	# Only trigger targets in a single bucket based on bringup
	if target.bringup:
	staging_target_args["triggered_by"] = [trigger_name] if target.scheduler == SCHEDULER_LUCI else None
	staging_target_args["triggering_policy"] = final_triggering_policy
	else:
	prod_target_args["triggered_by"] = [trigger_name] if target.scheduler == SCHEDULER_LUCI else None
	prod_target_args["triggering_policy"] = final_triggering_policy

	# Both staging and prod builders are generated to retain information and make it easy to swap
	common.common_prod_builder(**prod_target_args)
	common.common_prod_builder(**staging_target_args)

	def _target_platform(target):
	"""Return the target platform based on the name."""
	platform = target.name.split(" ")[0]
	return platform.lower()

	def _generate(repo, branch, version, testing_ref, dimensions = {}, properties = {}, triggering_policy = None, notifies = None, recipes_ref = "refs/heads/main"):
	# CQ group configurations. Only FLUTTER_RECIPES is using
	# LUCI CQ but we still need the CQ configurations for all
	# the try configurations for led recipe tests.
	if _is_default_branch(branch):
	common.cq_group(repos.GIT_REMOTE[repo])
	_recipes(repo, branch, recipes_ref)
	_builders(repo, branch, version, testing_ref, dimensions, properties, triggering_policy, notifies = notifies, recipes_ref = recipes_ref)

	ci_yaml = struct(
	builder_name = _builder_name,
	ci_yaml = _ci_yaml,
	full_recipe_name = _full_recipe_name,
	generate = _generate,
	legacy_swarming_caches = _legacy_swarming_caches,
	platform_properties = _platform_properties,
	properties = _properties,
	swarming_caches = _swarming_caches,
	)