Syntax overview (original) (raw)

To create a workflow, you use the Workflows syntax to define the steps you want and their order of execution. For more information about creating workflows, see Create and manage workflows.

For other functions available in addition to the core syntax, refer to theStandard library andConnectors references.

File structure

Workflow source files have the following characteristics:

• They contain only one main workflow.
• They might contain subworkflows.
• They are either a valid YAML orJSON file.
  Code samples are provided in both YAML and the equivalent JSON.

Search the syntax

You can search the Workflows syntax for its reserved words and other details. To see examples of the syntax in action, see thecheat sheet.

Example: `` args

YAML

• STEP_NAME: call: ... args: ... result: VARIABLE

JSON

[ { "STEP_NAME": { "call": ..., "args": { ... }, "result": "VARIABLE" } } ]

Example: assign

YAML

• STEP_NAME: assign: - VARIABLE_NAME: VALUE

JSON

[ { "STEP_NAME": { "assign": [ { "VARIABLE_NAME": "VALUE" } ] } } ]

Example: branches

YAML

• PARALLEL_STEP_NAME: parallel: ... branches: - BRANCH_NAME_A: steps: ... - BRANCH_NAME_B: steps: ...

JSON

[ { "PARALLEL_STEP_NAME": { "parallel": { ... "branches": [ { "BRANCH_NAME_A": { "steps": ... } }, { "BRANCH_NAME_B": { "steps": ... } } ] } } } ]

Example: break

YAML

• FOR_LOOP_STEP_NAME_A: for: value: LOOP_VARIABLE_NAME_A in: ${LIST_EXPRESSION_A} # or simply in: LIST_DEFINITION steps: - STEP_NAME_A: next: continue
• FOR_LOOP_STEP_NAME_B: for: value: LOOP_VARIABLE_NAME_B range: [${BEGIN_EXPRESSION}, ${END_EXPRESSION}] steps: - STEP_NAME_B: next: break

JSON

[ { "FOR_LOOP_STEP_NAME_A": { "for": { "value": "LOOP_VARIABLE_NAME_A", "in": "${LIST_EXPRESSION_A}", "steps": [ { "STEP_NAME_A": { "next": "continue" } } ] } } }, { "FOR_LOOP_STEP_NAME_B": { "for": { "value": "LOOP_VARIABLE_NAME_B", "range": [ "${BEGIN_EXPRESSION}", "${END_EXPRESSION}" ], "steps": [ { "STEP_NAME_B": { "next": "break" } } ] } } } ]

Example: call

YAML

• STEP_NAME: call: ... args: ... result: VARIABLE

JSON

[ { "STEP_NAME": { "call": ..., "args": { ... }, "result": "VARIABLE" } } ]

Example: condition

YAML

• STEP_NAME_A: switch: - condition: ${EXPRESSION_A} next: STEP_NAME_B - condition: ${EXPRESSION_B} next: STEP_NAME_C - condition: true next: STEP_NAME_C next: STEP_NAME_D

JSON

[ { "STEP_NAME_A": { "switch": [ { "condition": "${EXPRESSION_A}", "next": "STEP_NAME_B" }, { "condition": "${EXPRESSION_B}", "next": "STEP_NAME_C" } { "condition": true, "next": "STEP_NAME_C" } ], "next": "STEP_NAME_D" } } ]

Example: continue

YAML

• FOR_LOOP_STEP_NAME_A: for: value: LOOP_VARIABLE_NAME_A in: ${LIST_EXPRESSION_A} # or simply in: LIST_DEFINITION steps: - STEP_NAME_A: next: continue
• FOR_LOOP_STEP_NAME_B: for: value: LOOP_VARIABLE_NAME_B range: [${BEGIN_EXPRESSION}, ${END_EXPRESSION}] steps: - STEP_NAME_B: next: break

JSON

[ { "FOR_LOOP_STEP_NAME_A": { "for": { "value": "LOOP_VARIABLE_NAME_A", "in": "${LIST_EXPRESSION_A}", "steps": [ { "STEP_NAME_A": { "next": "continue" } } ] } } }, { "FOR_LOOP_STEP_NAME_B": { "for": { "value": "LOOP_VARIABLE_NAME_B", "range": [ "${BEGIN_EXPRESSION}", "${END_EXPRESSION}" ], "steps": [ { "STEP_NAME_B": { "next": "break" } } ] } } } ]

Example: end

YAML

• STEP_NAME: ... next: end

JSON

[ { "STEP_NAME": { ... "next": "end" } } ]

Example: except

YAML

• STEP_NAME: try: call: http.get ... except: as: ERROR_MAP steps: ...

JSON

[ { "STEP_NAME": { "try": { "call": "http.get" ... }, "except": { "as": "ERROR_MAP", "steps": ... } } } ]

Example: for

YAML

• FOR_LOOP_STEP_NAME: for: value: LOOP_VARIABLE_NAME index: INDEX_VARIABLE_NAME in: ${LIST_EXPRESSION} steps: - STEP_NAME_A: ...

JSON

[ { "FOR_LOOP_STEP_NAME": { "for": { "value": "LOOP_VARIABLE_NAME", "index": "INDEX_VARIABLE_NAME", "in": "${LIST_EXPRESSION}", "steps": [ { "STEP_NAME_A": ... } ] } } } ]

Example: main

YAML

main: params: [MAP_NAME] steps: - STEP_NAME: ... ...

JSON

{
  "**main**": {
    "params": [
      "MAP_NAME"
    ],
    "steps": [
      {
        "STEP_NAME": {
          ...
        }
      },
      ...
    ]
  }
}

Example: next

YAML

• STEP_NAME: ... next: STEP_NAME_TO_JUMP_TO

JSON

[ { "STEP_NAME": { ... "next": "STEP_NAME_TO_JUMP_TO" } } ]

Example: params

YAML

main: steps: - STEP_NAME: call: SUBWORKFLOW_NAME args: ARG_1: VALUE_1 ARG_2: VALUE_2 ... result: OUTPUT_VARIABLE SUBWORKFLOW_NAME: params: [PARAMETER_1,PARAMETER_2...] steps: - step_1: ...

JSON

{ "main": { "steps": [ { "STEP_NAME": { "call": "SUBWORKFLOW_NAME", "args": { "ARG_1": "VALUE_1", "ARG_2": "VALUE_2" }, "result": "OUTPUT_VARIABLE" } } ] }, "SUBWORKFLOW_NAME": { "params": ["PARAMETER_1,PARAMETER_2"...], "steps": [ { "step_1": ... } ] } }

Example: parallel

YAML

• PARALLEL_STEP_NAME: parallel: exception_policy: POLICY shared: [VARIABLE_A, VARIABLE_B, ...] BRANCHES_OR_FOR: ...

JSON

[ { "PARALLEL_STEP_NAME": { "parallel": { "exception_policy": "POLICY", "shared": [ "VARIABLE_A", "VARIABLE_B", ... ], "BRANCHES_OR_FOR": ... } } } ]

Example: raise

YAML

• step_a: raise: "Something went wrong."

JSON

[ { "step_a": { "raise": "Something went wrong." } } ]

Example: result

YAML

• STEP_NAME: call: ... args: ... result: VARIABLE

JSON

[ { "STEP_NAME": { "call": ..., "args": ..., "result": "VARIABLE" } } ]

Example: retry

YAML

• step_name: try: steps: ... retry: RETRY_POLICY predicate: RETRY_PREDICATE max_retries: NUMBER_OF_RETRIES backoff: initial_delay: DELAY_SECONDS max_delay: MAX_DELAY_SECONDS multiplier: DELAY_MULTIPLIER

JSON

[ { "step_name": { "try": { "steps": [ ... ] }, "retry": "RETRY_POLICY" "predicate": "RETRY_PREDICATE", "max_retries": NUMBER_OF_RETRIES, "backoff": { "initial_delay": DELAY_SECONDS, "max_delay": MAX_DELAY_SECONDS, "multiplier": DELAY_MULTIPLIER } } } ]

Example: return

YAML

• STEP_NAME: ... return: ${VARIABLE}

JSON

[ { "STEP_NAME": { ... "return": "${VARIABLE}" } } ]

Example: steps

YAML

• STEP_NAME: steps:
  • STEP_NAME_1: steps: - STEP_NAME_A: ... - STEP_NAME_B: ...
  • STEP_NAME_2: steps: - STEP_NAME_C: ...

JSON

{
  STEP_NAME: {
  "**steps**": [
    {
      STEP_NAME_1: {
        "**steps**": [
          {
            STEP_NAME_A:
              ...
          },
          {
            STEP_NAME_B:
              ...
          }
        ]
      }
    },
    {
      STEP_NAME_2: {
        "**steps**": [
          {
            STEP_NAME_C:
              ...
          }
        ]
      }
    }
  ]
}

}

Example: switch

YAML

• STEP_NAME_A: switch: - condition: ${EXPRESSION_A} next: STEP_NAME_B - condition: ${EXPRESSION_B} next: STEP_NAME_C - condition: true next: STEP_NAME_C next: STEP_NAME_D

JSON

[ { "STEP_NAME_A": { "switch": [ { "condition": "${EXPRESSION_A}", "next": "STEP_NAME_B" }, { "condition": "${EXPRESSION_B}", "next": "STEP_NAME_C" } { "condition": true, "next": "STEP_NAME_C" } ], "next": "STEP_NAME_D" } } ]

Example: try

YAML

• STEP_NAME: try: call: http.get ... except: as: ERROR_MAP steps: ...

JSON

[ { "STEP_NAME": { "try": { "call": "http.get" ... }, "except": { "as": "ERROR_MAP", "steps": ... } } } ]

Example: stub

Using code samples

For all samples that communicate with other Google Cloud resources, your workflow must be associated with a service account that has sufficient privileges to access those resources. To learn more about granting roles to service accounts, seeManage access to projects, folders, and organizations. To learn how to change the service account associated with a workflow, seeupdate a workflow. For more information about authentication, seeGrant a workflow permission to access Google Cloud resources.

Some samples might require that you first enable a Google Cloud API. Learn more about listing services andenabling services.

See all Workflows code samples.

Notation key