diff --git a/recipe_modules/shard_util_v2/api.py b/recipe_modules/shard_util_v2/api.py
index 208fc4b..7ed317e 100644
--- a/recipe_modules/shard_util_v2/api.py
+++ b/recipe_modules/shard_util_v2/api.py
@@ -161,7 +161,7 @@
       # Override recipe.
       drone_properties['recipe'] = recipe_name
 
-      environment = drone_properties['environment']
+      environment = drone_properties.get('environment')
       bucket = self.m.buildbucket.build.builder.bucket
       environment = '%s ' % environment if environment else ''
       environment = '' if bucket == 'try' else environment
diff --git a/recipes/engine/release_builder.expected/basic_linux.json b/recipes/engine/release_builder.expected/basic_linux.json
new file mode 100644
index 0000000..d194576
--- /dev/null
+++ b/recipes/engine/release_builder.expected/basic_linux.json
@@ -0,0 +1,526 @@
+[
+  {
+    "cmd": [],
+    "name": "Checkout flutter/engine"
+  },
+  {
+    "cmd": [
+      "python3",
+      "-u",
+      "RECIPE_MODULE[depot_tools::git]/resources/git_setup.py",
+      "--path",
+      "[START_DIR]/engine",
+      "--url",
+      "https://flutter.googlesource.com/mirrors/engine"
+    ],
+    "luci_context": {
+      "realm": {
+        "name": "proj:try"
+      },
+      "resultdb": {
+        "current_invocation": {
+          "name": "invocations/build:8945511751514863184",
+          "update_token": "token"
+        },
+        "hostname": "rdbhost"
+      }
+    },
+    "name": "Checkout flutter/engine.git setup",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "git",
+      "fetch",
+      "origin",
+      "--recurse-submodules",
+      "--progress",
+      "--tags"
+    ],
+    "cwd": "[START_DIR]/engine",
+    "env": {
+      "PATH": "RECIPE_REPO[depot_tools]:<PATH>"
+    },
+    "infra_step": true,
+    "luci_context": {
+      "realm": {
+        "name": "proj:try"
+      },
+      "resultdb": {
+        "current_invocation": {
+          "name": "invocations/build:8945511751514863184",
+          "update_token": "token"
+        },
+        "hostname": "rdbhost"
+      }
+    },
+    "name": "Checkout flutter/engine.git fetch",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "git",
+      "checkout",
+      "-f",
+      "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+    ],
+    "cwd": "[START_DIR]/engine",
+    "infra_step": true,
+    "luci_context": {
+      "realm": {
+        "name": "proj:try"
+      },
+      "resultdb": {
+        "current_invocation": {
+          "name": "invocations/build:8945511751514863184",
+          "update_token": "token"
+        },
+        "hostname": "rdbhost"
+      }
+    },
+    "name": "Checkout flutter/engine.git checkout",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "git",
+      "rev-parse",
+      "HEAD"
+    ],
+    "cwd": "[START_DIR]/engine",
+    "infra_step": true,
+    "luci_context": {
+      "realm": {
+        "name": "proj:try"
+      },
+      "resultdb": {
+        "current_invocation": {
+          "name": "invocations/build:8945511751514863184",
+          "update_token": "token"
+        },
+        "hostname": "rdbhost"
+      }
+    },
+    "name": "Checkout flutter/engine.read revision",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@",
+      "@@@STEP_TEXT@<br/>checked out 'deadbeef'<br/>@@@",
+      "@@@SET_BUILD_PROPERTY@got_revision@\"deadbeef\"@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "git",
+      "clean",
+      "-f",
+      "-d",
+      "-x"
+    ],
+    "cwd": "[START_DIR]/engine",
+    "infra_step": true,
+    "luci_context": {
+      "realm": {
+        "name": "proj:try"
+      },
+      "resultdb": {
+        "current_invocation": {
+          "name": "invocations/build:8945511751514863184",
+          "update_token": "token"
+        },
+        "hostname": "rdbhost"
+      }
+    },
+    "name": "Checkout flutter/engine.git clean",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "git",
+      "submodule",
+      "sync"
+    ],
+    "cwd": "[START_DIR]/engine",
+    "infra_step": true,
+    "luci_context": {
+      "realm": {
+        "name": "proj:try"
+      },
+      "resultdb": {
+        "current_invocation": {
+          "name": "invocations/build:8945511751514863184",
+          "update_token": "token"
+        },
+        "hostname": "rdbhost"
+      }
+    },
+    "name": "Checkout flutter/engine.submodule sync",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "git",
+      "submodule",
+      "update",
+      "--init",
+      "--recursive"
+    ],
+    "cwd": "[START_DIR]/engine",
+    "infra_step": true,
+    "luci_context": {
+      "realm": {
+        "name": "proj:try"
+      },
+      "resultdb": {
+        "current_invocation": {
+          "name": "invocations/build:8945511751514863184",
+          "update_token": "token"
+        },
+        "hostname": "rdbhost"
+      }
+    },
+    "name": "Checkout flutter/engine.submodule update",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [],
+    "name": "read ci yaml",
+    "~followup_annotations": [
+      "@@@STEP_LOG_LINE@yaml@@@@",
+      "@@@STEP_LOG_END@yaml@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "vpython3",
+      "-u",
+      "RECIPE_MODULE[recipe_engine::file]/resources/fileutil.py",
+      "--json-output",
+      "/path/to/tmp/json",
+      "copy",
+      "[START_DIR]/engine/.ci.yaml",
+      "/path/to/tmp/"
+    ],
+    "infra_step": true,
+    "luci_context": {
+      "realm": {
+        "name": "proj:try"
+      },
+      "resultdb": {
+        "current_invocation": {
+          "name": "invocations/build:8945511751514863184",
+          "update_token": "token"
+        },
+        "hostname": "rdbhost"
+      }
+    },
+    "name": "read ci yaml.read",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@",
+      "@@@STEP_LOG_END@.ci.yaml@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "vpython",
+      "RECIPE_MODULE[flutter::yaml]/resources/parse_yaml.py",
+      "--yaml_file",
+      "[START_DIR]/engine/.ci.yaml",
+      "--json_file",
+      "/path/to/tmp/json"
+    ],
+    "infra_step": true,
+    "luci_context": {
+      "realm": {
+        "name": "proj:try"
+      },
+      "resultdb": {
+        "current_invocation": {
+          "name": "invocations/build:8945511751514863184",
+          "update_token": "token"
+        },
+        "hostname": "rdbhost"
+      }
+    },
+    "name": "read ci yaml.parse",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@",
+      "@@@STEP_LOG_LINE@json.output@{@@@",
+      "@@@STEP_LOG_LINE@json.output@  \"targets\": [@@@",
+      "@@@STEP_LOG_LINE@json.output@    {@@@",
+      "@@@STEP_LOG_LINE@json.output@      \"name\": \"linux one\", @@@",
+      "@@@STEP_LOG_LINE@json.output@      \"properties\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@        \"release_build\": true@@@",
+      "@@@STEP_LOG_LINE@json.output@      }, @@@",
+      "@@@STEP_LOG_LINE@json.output@      \"recipe\": \"engine/something\"@@@",
+      "@@@STEP_LOG_LINE@json.output@    }@@@",
+      "@@@STEP_LOG_LINE@json.output@  ]@@@",
+      "@@@STEP_LOG_LINE@json.output@}@@@",
+      "@@@STEP_LOG_END@json.output@@@"
+    ]
+  },
+  {
+    "cmd": [],
+    "name": "launch builds"
+  },
+  {
+    "cmd": [
+      "bb",
+      "batch",
+      "-host",
+      "cr-buildbucket.appspot.com"
+    ],
+    "infra_step": true,
+    "luci_context": {
+      "realm": {
+        "name": "proj:try"
+      },
+      "resultdb": {
+        "current_invocation": {
+          "name": "invocations/build:8945511751514863184",
+          "update_token": "token"
+        },
+        "hostname": "rdbhost"
+      }
+    },
+    "name": "launch builds.schedule",
+    "stdin": "{\"requests\": [{\"scheduleBuild\": {\"builder\": {\"bucket\": \"try\", \"builder\": \"Linux Engine Drone\", \"project\": \"proj\"}, \"exe\": {\"cipdVersion\": \"refs/heads/main\"}, \"experimental\": \"NO\", \"experiments\": {\"luci.buildbucket.parent_tracking\": false}, \"fields\": \"builder,createTime,createdBy,critical,endTime,id,infra,input,number,output,startTime,status,updateTime\", \"gerritChanges\": [{\"change\": \"123456\", \"host\": \"flutter-review.googlesource.com\", \"patchset\": \"7\", \"project\": \"mirrors/engine\"}], \"gitilesCommit\": {\"host\": \"flutter.googlesource.com\", \"id\": \"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\", \"project\": \"mirrors/engine\", \"ref\": \"refs/heads/main\"}, \"priority\": 25, \"properties\": {\"build\": {\"name\": \"linux one\", \"properties\": {\"release_build\": true}, \"recipe\": \"engine/something\"}, \"environment\": \"Staging\", \"recipe\": \"engine/something\"}, \"requestId\": \"8945511751514863184-00000000-0000-0000-0000-000000001337\", \"swarming\": {\"parentRunId\": \"fake-task-id\"}, \"tags\": [{\"key\": \"cq_experimental\", \"value\": \"false\"}, {\"key\": \"parent_buildbucket_id\", \"value\": \"8945511751514863184\"}, {\"key\": \"user_agent\", \"value\": \"recipe\"}]}}]}",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@",
+      "@@@STEP_LOG_LINE@json.output@{@@@",
+      "@@@STEP_LOG_LINE@json.output@  \"responses\": [@@@",
+      "@@@STEP_LOG_LINE@json.output@    {@@@",
+      "@@@STEP_LOG_LINE@json.output@      \"scheduleBuild\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@        \"builder\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@          \"bucket\": \"try\", @@@",
+      "@@@STEP_LOG_LINE@json.output@          \"builder\": \"builder-subbuild1\", @@@",
+      "@@@STEP_LOG_LINE@json.output@          \"project\": \"fuchsia\"@@@",
+      "@@@STEP_LOG_LINE@json.output@        }, @@@",
+      "@@@STEP_LOG_LINE@json.output@        \"id\": \"8945511751514863186\"@@@",
+      "@@@STEP_LOG_LINE@json.output@      }@@@",
+      "@@@STEP_LOG_LINE@json.output@    }@@@",
+      "@@@STEP_LOG_LINE@json.output@  ]@@@",
+      "@@@STEP_LOG_LINE@json.output@}@@@",
+      "@@@STEP_LOG_END@json.output@@@",
+      "@@@STEP_LOG_LINE@request@{@@@",
+      "@@@STEP_LOG_LINE@request@  \"requests\": [@@@",
+      "@@@STEP_LOG_LINE@request@    {@@@",
+      "@@@STEP_LOG_LINE@request@      \"scheduleBuild\": {@@@",
+      "@@@STEP_LOG_LINE@request@        \"builder\": {@@@",
+      "@@@STEP_LOG_LINE@request@          \"bucket\": \"try\", @@@",
+      "@@@STEP_LOG_LINE@request@          \"builder\": \"Linux Engine Drone\", @@@",
+      "@@@STEP_LOG_LINE@request@          \"project\": \"proj\"@@@",
+      "@@@STEP_LOG_LINE@request@        }, @@@",
+      "@@@STEP_LOG_LINE@request@        \"exe\": {@@@",
+      "@@@STEP_LOG_LINE@request@          \"cipdVersion\": \"refs/heads/main\"@@@",
+      "@@@STEP_LOG_LINE@request@        }, @@@",
+      "@@@STEP_LOG_LINE@request@        \"experimental\": \"NO\", @@@",
+      "@@@STEP_LOG_LINE@request@        \"experiments\": {@@@",
+      "@@@STEP_LOG_LINE@request@          \"luci.buildbucket.parent_tracking\": false@@@",
+      "@@@STEP_LOG_LINE@request@        }, @@@",
+      "@@@STEP_LOG_LINE@request@        \"fields\": \"builder,createTime,createdBy,critical,endTime,id,infra,input,number,output,startTime,status,updateTime\", @@@",
+      "@@@STEP_LOG_LINE@request@        \"gerritChanges\": [@@@",
+      "@@@STEP_LOG_LINE@request@          {@@@",
+      "@@@STEP_LOG_LINE@request@            \"change\": \"123456\", @@@",
+      "@@@STEP_LOG_LINE@request@            \"host\": \"flutter-review.googlesource.com\", @@@",
+      "@@@STEP_LOG_LINE@request@            \"patchset\": \"7\", @@@",
+      "@@@STEP_LOG_LINE@request@            \"project\": \"mirrors/engine\"@@@",
+      "@@@STEP_LOG_LINE@request@          }@@@",
+      "@@@STEP_LOG_LINE@request@        ], @@@",
+      "@@@STEP_LOG_LINE@request@        \"gitilesCommit\": {@@@",
+      "@@@STEP_LOG_LINE@request@          \"host\": \"flutter.googlesource.com\", @@@",
+      "@@@STEP_LOG_LINE@request@          \"id\": \"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\", @@@",
+      "@@@STEP_LOG_LINE@request@          \"project\": \"mirrors/engine\", @@@",
+      "@@@STEP_LOG_LINE@request@          \"ref\": \"refs/heads/main\"@@@",
+      "@@@STEP_LOG_LINE@request@        }, @@@",
+      "@@@STEP_LOG_LINE@request@        \"priority\": 25, @@@",
+      "@@@STEP_LOG_LINE@request@        \"properties\": {@@@",
+      "@@@STEP_LOG_LINE@request@          \"build\": {@@@",
+      "@@@STEP_LOG_LINE@request@            \"name\": \"linux one\", @@@",
+      "@@@STEP_LOG_LINE@request@            \"properties\": {@@@",
+      "@@@STEP_LOG_LINE@request@              \"release_build\": true@@@",
+      "@@@STEP_LOG_LINE@request@            }, @@@",
+      "@@@STEP_LOG_LINE@request@            \"recipe\": \"engine/something\"@@@",
+      "@@@STEP_LOG_LINE@request@          }, @@@",
+      "@@@STEP_LOG_LINE@request@          \"environment\": \"Staging\", @@@",
+      "@@@STEP_LOG_LINE@request@          \"recipe\": \"engine/something\"@@@",
+      "@@@STEP_LOG_LINE@request@        }, @@@",
+      "@@@STEP_LOG_LINE@request@        \"requestId\": \"8945511751514863184-00000000-0000-0000-0000-000000001337\", @@@",
+      "@@@STEP_LOG_LINE@request@        \"swarming\": {@@@",
+      "@@@STEP_LOG_LINE@request@          \"parentRunId\": \"fake-task-id\"@@@",
+      "@@@STEP_LOG_LINE@request@        }, @@@",
+      "@@@STEP_LOG_LINE@request@        \"tags\": [@@@",
+      "@@@STEP_LOG_LINE@request@          {@@@",
+      "@@@STEP_LOG_LINE@request@            \"key\": \"cq_experimental\", @@@",
+      "@@@STEP_LOG_LINE@request@            \"value\": \"false\"@@@",
+      "@@@STEP_LOG_LINE@request@          }, @@@",
+      "@@@STEP_LOG_LINE@request@          {@@@",
+      "@@@STEP_LOG_LINE@request@            \"key\": \"parent_buildbucket_id\", @@@",
+      "@@@STEP_LOG_LINE@request@            \"value\": \"8945511751514863184\"@@@",
+      "@@@STEP_LOG_LINE@request@          }, @@@",
+      "@@@STEP_LOG_LINE@request@          {@@@",
+      "@@@STEP_LOG_LINE@request@            \"key\": \"user_agent\", @@@",
+      "@@@STEP_LOG_LINE@request@            \"value\": \"recipe\"@@@",
+      "@@@STEP_LOG_LINE@request@          }@@@",
+      "@@@STEP_LOG_LINE@request@        ]@@@",
+      "@@@STEP_LOG_LINE@request@      }@@@",
+      "@@@STEP_LOG_LINE@request@    }@@@",
+      "@@@STEP_LOG_LINE@request@  ]@@@",
+      "@@@STEP_LOG_LINE@request@}@@@",
+      "@@@STEP_LOG_END@request@@@",
+      "@@@STEP_LINK@8945511751514863186@https://cr-buildbucket.appspot.com/build/8945511751514863186@@@"
+    ]
+  },
+  {
+    "cmd": [],
+    "name": "collect builds"
+  },
+  {
+    "cmd": [],
+    "name": "collect builds.collect",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "bb",
+      "collect",
+      "-host",
+      "cr-buildbucket.appspot.com",
+      "-interval",
+      "20s",
+      "8945511751514863186"
+    ],
+    "infra_step": true,
+    "luci_context": {
+      "realm": {
+        "name": "proj:try"
+      },
+      "resultdb": {
+        "current_invocation": {
+          "name": "invocations/build:8945511751514863184",
+          "update_token": "token"
+        },
+        "hostname": "rdbhost"
+      }
+    },
+    "name": "collect builds.collect.wait",
+    "timeout": 86400,
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@2@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "bb",
+      "batch",
+      "-host",
+      "cr-buildbucket.appspot.com"
+    ],
+    "infra_step": true,
+    "luci_context": {
+      "realm": {
+        "name": "proj:try"
+      },
+      "resultdb": {
+        "current_invocation": {
+          "name": "invocations/build:8945511751514863184",
+          "update_token": "token"
+        },
+        "hostname": "rdbhost"
+      }
+    },
+    "name": "collect builds.collect.get",
+    "stdin": "{\"requests\": [{\"getBuild\": {\"fields\": \"builder,createTime,createdBy,critical,endTime,id,infra,infra.swarming.taskId,input,number,output,startTime,status,summaryMarkdown,updateTime\", \"id\": \"8945511751514863186\"}}]}",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@2@@@",
+      "@@@STEP_LOG_LINE@json.output@{@@@",
+      "@@@STEP_LOG_LINE@json.output@  \"responses\": [@@@",
+      "@@@STEP_LOG_LINE@json.output@    {@@@",
+      "@@@STEP_LOG_LINE@json.output@      \"getBuild\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@        \"builder\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@          \"bucket\": \"try\", @@@",
+      "@@@STEP_LOG_LINE@json.output@          \"builder\": \"builder-subbuild1\", @@@",
+      "@@@STEP_LOG_LINE@json.output@          \"project\": \"fuchsia\"@@@",
+      "@@@STEP_LOG_LINE@json.output@        }, @@@",
+      "@@@STEP_LOG_LINE@json.output@        \"createTime\": \"2018-05-25T23:50:17Z\", @@@",
+      "@@@STEP_LOG_LINE@json.output@        \"createdBy\": \"project:fuchsia\", @@@",
+      "@@@STEP_LOG_LINE@json.output@        \"id\": \"8945511751514863186\", @@@",
+      "@@@STEP_LOG_LINE@json.output@        \"infra\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@          \"resultdb\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@            \"invocation\": \"invocations/build:8945511751514863186\"@@@",
+      "@@@STEP_LOG_LINE@json.output@          }, @@@",
+      "@@@STEP_LOG_LINE@json.output@          \"swarming\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@            \"priority\": 30, @@@",
+      "@@@STEP_LOG_LINE@json.output@            \"taskId\": \"abc123\"@@@",
+      "@@@STEP_LOG_LINE@json.output@          }@@@",
+      "@@@STEP_LOG_LINE@json.output@        }, @@@",
+      "@@@STEP_LOG_LINE@json.output@        \"input\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@          \"gerritChanges\": [@@@",
+      "@@@STEP_LOG_LINE@json.output@            {@@@",
+      "@@@STEP_LOG_LINE@json.output@              \"change\": \"123456\", @@@",
+      "@@@STEP_LOG_LINE@json.output@              \"host\": \"chromium-review.googlesource.com\", @@@",
+      "@@@STEP_LOG_LINE@json.output@              \"patchset\": \"7\", @@@",
+      "@@@STEP_LOG_LINE@json.output@              \"project\": \"fuchsia\"@@@",
+      "@@@STEP_LOG_LINE@json.output@            }@@@",
+      "@@@STEP_LOG_LINE@json.output@          ]@@@",
+      "@@@STEP_LOG_LINE@json.output@        }, @@@",
+      "@@@STEP_LOG_LINE@json.output@        \"output\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@          \"properties\": {@@@",
+      "@@@STEP_LOG_LINE@json.output@            \"test_orchestration_inputs_hash\": \"abc\"@@@",
+      "@@@STEP_LOG_LINE@json.output@          }@@@",
+      "@@@STEP_LOG_LINE@json.output@        }, @@@",
+      "@@@STEP_LOG_LINE@json.output@        \"status\": \"SUCCESS\", @@@",
+      "@@@STEP_LOG_LINE@json.output@        \"tags\": [@@@",
+      "@@@STEP_LOG_LINE@json.output@          {@@@",
+      "@@@STEP_LOG_LINE@json.output@            \"key\": \"cq_experimental\", @@@",
+      "@@@STEP_LOG_LINE@json.output@            \"value\": \"false\"@@@",
+      "@@@STEP_LOG_LINE@json.output@          }@@@",
+      "@@@STEP_LOG_LINE@json.output@        ]@@@",
+      "@@@STEP_LOG_LINE@json.output@      }@@@",
+      "@@@STEP_LOG_LINE@json.output@    }@@@",
+      "@@@STEP_LOG_LINE@json.output@  ]@@@",
+      "@@@STEP_LOG_LINE@json.output@}@@@",
+      "@@@STEP_LOG_END@json.output@@@",
+      "@@@STEP_LOG_LINE@request@{@@@",
+      "@@@STEP_LOG_LINE@request@  \"requests\": [@@@",
+      "@@@STEP_LOG_LINE@request@    {@@@",
+      "@@@STEP_LOG_LINE@request@      \"getBuild\": {@@@",
+      "@@@STEP_LOG_LINE@request@        \"fields\": \"builder,createTime,createdBy,critical,endTime,id,infra,infra.swarming.taskId,input,number,output,startTime,status,summaryMarkdown,updateTime\", @@@",
+      "@@@STEP_LOG_LINE@request@        \"id\": \"8945511751514863186\"@@@",
+      "@@@STEP_LOG_LINE@request@      }@@@",
+      "@@@STEP_LOG_LINE@request@    }@@@",
+      "@@@STEP_LOG_LINE@request@  ]@@@",
+      "@@@STEP_LOG_LINE@request@}@@@",
+      "@@@STEP_LOG_END@request@@@",
+      "@@@STEP_LINK@8945511751514863186@https://cr-buildbucket.appspot.com/build/8945511751514863186@@@"
+    ]
+  },
+  {
+    "cmd": [],
+    "name": "display builds"
+  },
+  {
+    "cmd": [],
+    "name": "display builds.linux one",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@",
+      "@@@STEP_LINK@8945511751514863186@https://cr-buildbucket.appspot.com/build/8945511751514863186@@@"
+    ]
+  },
+  {
+    "name": "$result"
+  }
+]
\ No newline at end of file
diff --git a/recipes/engine/release_builder.py b/recipes/engine/release_builder.py
new file mode 100644
index 0000000..bb5ab00
--- /dev/null
+++ b/recipes/engine/release_builder.py
@@ -0,0 +1,98 @@
+# Copyright 2022 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# Orchestrator recipe that runs subbuilds required to release engine.
+#
+# This recipe reads <engine_checkout>/.ci_yaml, and for every target
+# marked with release_build: true, and spawens a subbuild.
+
+
+from contextlib import contextmanager
+
+from PB.recipes.flutter.engine.engine import InputProperties
+from PB.recipes.flutter.engine.engine import EnvProperties
+
+from google.protobuf import struct_pb2
+
+DEPS = [
+  'flutter/yaml',
+  'flutter/display_util',
+  'flutter/repo_util',
+  'flutter/shard_util_v2',
+  'recipe_engine/buildbucket',
+  'recipe_engine/json',
+  'recipe_engine/path',
+  'recipe_engine/platform',
+  'recipe_engine/properties',
+  'recipe_engine/step',
+]
+
+GIT_REPO = \
+  'https://flutter.googlesource.com/mirrors/engine'
+
+
+PROPERTIES = InputProperties
+ENV_PROPERTIES = EnvProperties
+
+
+def RunSteps(api, properties, env_properties):
+  repository = 'engine'
+  checkout_path = api.path['start_dir'].join(repository)
+  api.repo_util.checkout(
+    repository,
+    checkout_path=checkout_path,
+    url=api.properties.get('git_url'),
+    ref=api.properties.get('git_ref')
+  )
+
+  ci_yaml_path = checkout_path.join('.ci.yaml')
+  ci_yaml = api.yaml.read('read ci yaml', ci_yaml_path, api.json.output())
+
+  # Foreach target defined in .ci.yaml, if it contains
+  # release_build: True, then spawn a subbuild.
+  tasks = {}
+  build_results = []
+  with api.step.nest('launch builds') as presentation:
+    for target in ci_yaml.json.output['targets']:
+      if target.get("properties", {}).get("release_build", False) and (
+          target["name"].lower().startswith(api.platform.name)):
+        tasks.update(api.shard_util_v2.schedule(
+          [target, ], target["recipe"], presentation))
+  with api.step.nest('collect builds') as presentation:
+    build_results = api.shard_util_v2.collect(tasks, presentation)
+
+  api.display_util.display_subbuilds(
+    step_name='display builds',
+    subbuilds=build_results,
+    raise_on_failure=True,
+  )
+
+
+def GenTests(api):
+  try_subbuild1 = api.shard_util_v2.try_build_message(
+    build_id=8945511751514863186,
+    builder="builder-subbuild1",
+    output_props={"test_orchestration_inputs_hash": "abc"},
+    status="SUCCESS",
+  )
+  tasks_dict = {'targets': [
+    {'name': 'linux one', 'recipe': 'engine/something', 'properties': {'release_build': True, }}]}
+  yield api.test(
+    'basic_linux',
+    api.platform.name('linux'),
+    api.properties(environment='Staging'),
+    api.buildbucket.try_build(
+      project='proj',
+      builder='try-builder',
+      git_repo='https://flutter.googlesource.com/mirrors/engine',
+      revision='a' * 40,
+      build_number=123,
+    ),
+    api.shard_util_v2.child_build_steps(
+      subbuilds=[try_subbuild1],
+      launch_step="launch builds",
+      collect_step="collect builds",
+    ),
+    api.step_data('read ci yaml.parse', api.json.output(tasks_dict))
+  )