Add basic get_execution_history implementation for Step Functions (#3507)

* Add format command to makefile

* Refactor executions to be a attribute of StateMachine

* Begin to add tests for execution history

* Add tests for failed and successful event histories, with implementations

* Add failure case to environment var check

* Skip test if in server mode and update implementation coverage

* Add conditional import for mock to cover python 2

* Refactor stop execution logic into StateMachine

* Refactor event history environment variable into settings.py

* Remove typing and os import

IMPLEMENTATION_COVERAGE.md

@@ -8115,7 +8115,7 @@
 - [X] describe_state_machine
 - [ ] describe_state_machine_for_execution
 - [ ] get_activity_task
-- [ ] get_execution_history
+- [X] get_execution_history
 - [ ] list_activities
 - [X] list_executions
 - [X] list_state_machines

Makefile

@@ -20,12 +20,14 @@ lint:
 	flake8 moto
 	black --check moto/ tests/
 
+format:
+	black moto/ tests/
+
 test-only:
 	rm -f .coverage
 	rm -rf cover
 	@pytest -sv --cov=moto --cov-report html ./tests/ $(TEST_EXCLUDE)
 
-
 test: lint test-only
 
 test_server:

moto/settings.py

@@ -4,3 +4,12 @@ TEST_SERVER_MODE = os.environ.get("TEST_SERVER_MODE", "0").lower() == "true"
 INITIAL_NO_AUTH_ACTION_COUNT = float(
     os.environ.get("INITIAL_NO_AUTH_ACTION_COUNT", float("inf"))
 )
+
+
+def get_sf_execution_history_type():
+    """
+    Determines which execution history events `get_execution_history` returns
+    :returns: str representing the type of Step Function Execution Type events should be
+        returned. Default value is SUCCESS, currently supports (SUCCESS || FAILURE)
+    """
+    return os.environ.get("SF_EXECUTION_HISTORY_TYPE", "SUCCESS")

moto/stepfunctions/models.py

@@ -1,6 +1,7 @@
 import json
 import re
 from datetime import datetime
+from dateutil.tz import tzlocal
 
 from boto3 import Session
 
@@ -17,6 +18,7 @@ from .exceptions import (
     StateMachineDoesNotExist,
 )
 from .utils import paginate, api_to_cfn_tags, cfn_to_api_tags
+from moto import settings
 
 
 class StateMachine(CloudFormationModel):
@@ -27,10 +29,51 @@ class StateMachine(CloudFormationModel):
         self.name = name
         self.definition = definition
         self.roleArn = roleArn
+        self.executions = []
         self.tags = []
         if tags:
             self.add_tags(tags)
 
+    def start_execution(self, region_name, account_id, execution_name, execution_input):
+        self._ensure_execution_name_doesnt_exist(execution_name)
+        self._validate_execution_input(execution_input)
+        execution = Execution(
+            region_name=region_name,
+            account_id=account_id,
+            state_machine_name=self.name,
+            execution_name=execution_name,
+            state_machine_arn=self.arn,
+            execution_input=execution_input,
+        )
+        self.executions.append(execution)
+        return execution
+
+    def stop_execution(self, execution_arn):
+        execution = next(
+            (x for x in self.executions if x.execution_arn == execution_arn), None
+        )
+        if not execution:
+            raise ExecutionDoesNotExist(
+                "Execution Does Not Exist: '" + execution_arn + "'"
+            )
+        execution.stop()
+        return execution
+
+    def _ensure_execution_name_doesnt_exist(self, name):
+        for execution in self.executions:
+            if execution.name == name:
+                raise ExecutionAlreadyExists(
+                    "Execution Already Exists: '" + execution.execution_arn + "'"
+                )
+
+    def _validate_execution_input(self, execution_input):
+        try:
+            json.loads(execution_input)
+        except Exception as ex:
+            raise InvalidExecutionInput(
+                "Invalid State Machine Execution Input: '" + str(ex) + "'"
+            )
+
     def update(self, **kwargs):
         for key, value in kwargs.items():
             if value is not None:
@@ -176,6 +219,104 @@ class Execution:
         self.status = "RUNNING"
         self.stop_date = None
 
+    def get_execution_history(self, roleArn):
+        sf_execution_history_type = settings.get_sf_execution_history_type()
+        if sf_execution_history_type == "SUCCESS":
+            return [
+                {
+                    "timestamp": iso_8601_datetime_with_milliseconds(
+                        datetime(2020, 1, 1, 0, 0, 0, tzinfo=tzlocal())
+                    ),
+                    "type": "ExecutionStarted",
+                    "id": 1,
+                    "previousEventId": 0,
+                    "executionStartedEventDetails": {
+                        "input": "{}",
+                        "inputDetails": {"truncated": False},
+                        "roleArn": roleArn,
+                    },
+                },
+                {
+                    "timestamp": iso_8601_datetime_with_milliseconds(
+                        datetime(2020, 1, 1, 0, 0, 10, tzinfo=tzlocal())
+                    ),
+                    "type": "PassStateEntered",
+                    "id": 2,
+                    "previousEventId": 0,
+                    "stateEnteredEventDetails": {
+                        "name": "A State",
+                        "input": "{}",
+                        "inputDetails": {"truncated": False},
+                    },
+                },
+                {
+                    "timestamp": iso_8601_datetime_with_milliseconds(
+                        datetime(2020, 1, 1, 0, 0, 10, tzinfo=tzlocal())
+                    ),
+                    "type": "PassStateExited",
+                    "id": 3,
+                    "previousEventId": 2,
+                    "stateExitedEventDetails": {
+                        "name": "A State",
+                        "output": "An output",
+                        "outputDetails": {"truncated": False},
+                    },
+                },
+                {
+                    "timestamp": iso_8601_datetime_with_milliseconds(
+                        datetime(2020, 1, 1, 0, 0, 20, tzinfo=tzlocal())
+                    ),
+                    "type": "ExecutionSucceeded",
+                    "id": 4,
+                    "previousEventId": 3,
+                    "executionSucceededEventDetails": {
+                        "output": "An output",
+                        "outputDetails": {"truncated": False},
+                    },
+                },
+            ]
+        elif sf_execution_history_type == "FAILURE":
+            return [
+                {
+                    "timestamp": iso_8601_datetime_with_milliseconds(
+                        datetime(2020, 1, 1, 0, 0, 0, tzinfo=tzlocal())
+                    ),
+                    "type": "ExecutionStarted",
+                    "id": 1,
+                    "previousEventId": 0,
+                    "executionStartedEventDetails": {
+                        "input": "{}",
+                        "inputDetails": {"truncated": False},
+                        "roleArn": roleArn,
+                    },
+                },
+                {
+                    "timestamp": iso_8601_datetime_with_milliseconds(
+                        datetime(2020, 1, 1, 0, 0, 10, tzinfo=tzlocal())
+                    ),
+                    "type": "FailStateEntered",
+                    "id": 2,
+                    "previousEventId": 0,
+                    "stateEnteredEventDetails": {
+                        "name": "A State",
+                        "input": "{}",
+                        "inputDetails": {"truncated": False},
+                    },
+                },
+                {
+                    "timestamp": iso_8601_datetime_with_milliseconds(
+                        datetime(2020, 1, 1, 0, 0, 10, tzinfo=tzlocal())
+                    ),
+                    "type": "ExecutionFailed",
+                    "id": 3,
+                    "previousEventId": 2,
+                    "executionFailedEventDetails": {
+                        "error": "AnError",
+                        "cause": "An error occurred!",
+                    },
+                },
+            ]
+
     def stop(self):
         self.status = "ABORTED"
         self.stop_date = iso_8601_datetime_with_milliseconds(datetime.now())
@@ -346,38 +487,23 @@ class StepFunctionBackend(BaseBackend):
         return sm
 
     def start_execution(self, state_machine_arn, name=None, execution_input=None):
-        state_machine_name = self.describe_state_machine(state_machine_arn).name
-        self._ensure_execution_name_doesnt_exist(name)
-        self._validate_execution_input(execution_input)
-        execution = Execution(
+        state_machine = self.describe_state_machine(state_machine_arn)
+        execution = state_machine.start_execution(
             region_name=self.region_name,
             account_id=self._get_account_id(),
-            state_machine_name=state_machine_name,
             execution_name=name or str(uuid4()),
-            state_machine_arn=state_machine_arn,
             execution_input=execution_input,
         )
-        self.executions.append(execution)
         return execution
 
     def stop_execution(self, execution_arn):
-        execution = next(
-            (x for x in self.executions if x.execution_arn == execution_arn), None
-        )
-        if not execution:
-            raise ExecutionDoesNotExist(
-                "Execution Does Not Exist: '" + execution_arn + "'"
-            )
-        execution.stop()
-        return execution
+        self._validate_execution_arn(execution_arn)
+        state_machine = self._get_state_machine_for_execution(execution_arn)
+        return state_machine.stop_execution(execution_arn)
 
     @paginate
     def list_executions(self, state_machine_arn, status_filter=None):
-        executions = [
-            execution
-            for execution in self.executions
-            if execution.state_machine_arn == state_machine_arn
-        ]
+        executions = self.describe_state_machine(state_machine_arn).executions
 
         if status_filter:
             executions = list(filter(lambda e: e.status == status_filter, executions))
@@ -385,13 +511,32 @@ class StepFunctionBackend(BaseBackend):
         executions = sorted(executions, key=lambda x: x.start_date, reverse=True)
         return executions
 
-    def describe_execution(self, arn):
-        self._validate_execution_arn(arn)
-        exctn = next((x for x in self.executions if x.execution_arn == arn), None)
+    def describe_execution(self, execution_arn):
+        self._validate_execution_arn(execution_arn)
+        state_machine = self._get_state_machine_for_execution(execution_arn)
+        exctn = next(
+            (x for x in state_machine.executions if x.execution_arn == execution_arn),
+            None,
+        )
         if not exctn:
-            raise ExecutionDoesNotExist("Execution Does Not Exist: '" + arn + "'")
+            raise ExecutionDoesNotExist(
+                "Execution Does Not Exist: '" + execution_arn + "'"
+            )
         return exctn
 
+    def get_execution_history(self, execution_arn):
+        self._validate_execution_arn(execution_arn)
+        state_machine = self._get_state_machine_for_execution(execution_arn)
+        execution = next(
+            (x for x in state_machine.executions if x.execution_arn == execution_arn),
+            None,
+        )
+        if not execution:
+            raise ExecutionDoesNotExist(
+                "Execution Does Not Exist: '" + execution_arn + "'"
+            )
+        return execution.get_execution_history(state_machine.roleArn)
+
     def tag_resource(self, resource_arn, tags):
         try:
             state_machine = self.describe_state_machine(resource_arn)
@@ -444,20 +589,18 @@ class StepFunctionBackend(BaseBackend):
         if not arn or not match:
             raise InvalidArn(invalid_msg)
 
-    def _ensure_execution_name_doesnt_exist(self, name):
-        for execution in self.executions:
-            if execution.name == name:
-                raise ExecutionAlreadyExists(
-                    "Execution Already Exists: '" + execution.execution_arn + "'"
-                )
-
-    def _validate_execution_input(self, execution_input):
-        try:
-            json.loads(execution_input)
-        except Exception as ex:
-            raise InvalidExecutionInput(
-                "Invalid State Machine Execution Input: '" + str(ex) + "'"
+    def _get_state_machine_for_execution(self, execution_arn):
+        state_machine_name = execution_arn.split(":")[6]
+        state_machine_arn = next(
+            (x.arn for x in self.state_machines if x.name == state_machine_name), None
+        )
+        if not state_machine_arn:
+            # Assume that if the state machine arn is not present, then neither will the
+            # execution
+            raise ExecutionDoesNotExist(
+                "Execution Does Not Exist: '" + execution_arn + "'"
             )
+        return self.describe_state_machine(state_machine_arn)
 
     def _get_account_id(self):
         return ACCOUNT_ID

moto/stepfunctions/responses.py

@@ -208,6 +208,21 @@ class StepFunctionResponse(BaseResponse):
     @amzn_request_id
     def stop_execution(self):
         arn = self._get_param("executionArn")
-        execution = self.stepfunction_backend.stop_execution(arn)
-        response = {"stopDate": execution.stop_date}
-        return 200, {}, json.dumps(response)
+        try:
+            execution = self.stepfunction_backend.stop_execution(arn)
+            response = {"stopDate": execution.stop_date}
+            return 200, {}, json.dumps(response)
+        except AWSError as err:
+            return err.response()
+
+    @amzn_request_id
+    def get_execution_history(self):
+        execution_arn = self._get_param("executionArn")
+        try:
+            execution_history = self.stepfunction_backend.get_execution_history(
+                execution_arn
+            )
+            response = {"events": execution_history}
+            return 200, {}, json.dumps(response)
+        except AWSError as err:
+            return err.response()

tests/test_stepfunctions/test_stepfunctions.py

@@ -2,15 +2,23 @@ from __future__ import unicode_literals
 
 import boto3
 import json
+import os
 import sure  # noqa
-
+import sys
 from datetime import datetime
+from dateutil.tz import tzlocal
 from botocore.exceptions import ClientError
 import pytest
 
 from moto import mock_cloudformation, mock_sts, mock_stepfunctions
 from moto.core import ACCOUNT_ID
 
+if sys.version_info[0] < 3:
+    import mock
+    from unittest import SkipTest
+else:
+    from unittest import SkipTest, mock
+
 region = "us-east-1"
 simple_definition = (
     '{"Comment": "An example of the Amazon States Language using a choice state.",'
@@ -799,10 +807,30 @@ def test_state_machine_stop_execution():
 
 @mock_stepfunctions
 @mock_sts
-def test_state_machine_describe_execution_after_stoppage():
-    account_id
+def test_state_machine_stop_raises_error_when_unknown_execution():
+    client = boto3.client("stepfunctions", region_name=region)
+    client.create_state_machine(
+        name="test-state-machine",
+        definition=str(simple_definition),
+        roleArn=_get_default_role(),
+    )
+    with pytest.raises(ClientError) as ex:
+        unknown_execution = (
+            "arn:aws:states:"
+            + region
+            + ":"
+            + _get_account_id()
+            + ":execution:test-state-machine:unknown"
+        )
+        client.stop_execution(executionArn=unknown_execution)
+    ex.value.response["Error"]["Code"].should.equal("ExecutionDoesNotExist")
+    ex.value.response["Error"]["Message"].should.contain("Execution Does Not Exist:")
+
+
+@mock_stepfunctions
+@mock_sts
+def test_state_machine_describe_execution_after_stoppage():
     client = boto3.client("stepfunctions", region_name=region)
-    #
     sm = client.create_state_machine(
         name="name", definition=str(simple_definition), roleArn=_get_default_role()
     )
@@ -815,6 +843,146 @@ def test_state_machine_describe_execution_after_stoppage():
     description["stopDate"].should.be.a(datetime)
 
 
+@mock_stepfunctions
+@mock_sts
+def test_state_machine_get_execution_history_throws_error_with_unknown_execution():
+    client = boto3.client("stepfunctions", region_name=region)
+    client.create_state_machine(
+        name="test-state-machine",
+        definition=str(simple_definition),
+        roleArn=_get_default_role(),
+    )
+    with pytest.raises(ClientError) as ex:
+        unknown_execution = (
+            "arn:aws:states:"
+            + region
+            + ":"
+            + _get_account_id()
+            + ":execution:test-state-machine:unknown"
+        )
+        client.get_execution_history(executionArn=unknown_execution)
+    ex.value.response["Error"]["Code"].should.equal("ExecutionDoesNotExist")
+    ex.value.response["Error"]["Message"].should.contain("Execution Does Not Exist:")
+
+
+@mock_stepfunctions
+@mock_sts
+def test_state_machine_get_execution_history_contains_expected_success_events_when_started():
+    expected_events = [
+        {
+            "timestamp": datetime(2020, 1, 1, 0, 0, 0, tzinfo=tzlocal()),
+            "type": "ExecutionStarted",
+            "id": 1,
+            "previousEventId": 0,
+            "executionStartedEventDetails": {
+                "input": "{}",
+                "inputDetails": {"truncated": False},
+                "roleArn": _get_default_role(),
+            },
+        },
+        {
+            "timestamp": datetime(2020, 1, 1, 0, 0, 10, tzinfo=tzlocal()),
+            "type": "PassStateEntered",
+            "id": 2,
+            "previousEventId": 0,
+            "stateEnteredEventDetails": {
+                "name": "A State",
+                "input": "{}",
+                "inputDetails": {"truncated": False},
+            },
+        },
+        {
+            "timestamp": datetime(2020, 1, 1, 0, 0, 10, tzinfo=tzlocal()),
+            "type": "PassStateExited",
+            "id": 3,
+            "previousEventId": 2,
+            "stateExitedEventDetails": {
+                "name": "A State",
+                "output": "An output",
+                "outputDetails": {"truncated": False},
+            },
+        },
+        {
+            "timestamp": datetime(2020, 1, 1, 0, 0, 20, tzinfo=tzlocal()),
+            "type": "ExecutionSucceeded",
+            "id": 4,
+            "previousEventId": 3,
+            "executionSucceededEventDetails": {
+                "output": "An output",
+                "outputDetails": {"truncated": False},
+            },
+        },
+    ]
+
+    client = boto3.client("stepfunctions", region_name=region)
+    sm = client.create_state_machine(
+        name="test-state-machine",
+        definition=simple_definition,
+        roleArn=_get_default_role(),
+    )
+    execution = client.start_execution(stateMachineArn=sm["stateMachineArn"])
+    execution_history = client.get_execution_history(
+        executionArn=execution["executionArn"]
+    )
+    execution_history["events"].should.have.length_of(4)
+    execution_history["events"].should.equal(expected_events)
+
+
+@mock_stepfunctions
+@mock_sts
+@mock.patch.dict(os.environ, {"SF_EXECUTION_HISTORY_TYPE": "FAILURE"})
+def test_state_machine_get_execution_history_contains_expected_failure_events_when_started():
+    if os.environ.get("TEST_SERVER_MODE", "false").lower() == "true":
+        raise SkipTest("Cant pass environment variable in server mode")
+    expected_events = [
+        {
+            "timestamp": datetime(2020, 1, 1, 0, 0, 0, tzinfo=tzlocal()),
+            "type": "ExecutionStarted",
+            "id": 1,
+            "previousEventId": 0,
+            "executionStartedEventDetails": {
+                "input": "{}",
+                "inputDetails": {"truncated": False},
+                "roleArn": _get_default_role(),
+            },
+        },
+        {
+            "timestamp": datetime(2020, 1, 1, 0, 0, 10, tzinfo=tzlocal()),
+            "type": "FailStateEntered",
+            "id": 2,
+            "previousEventId": 0,
+            "stateEnteredEventDetails": {
+                "name": "A State",
+                "input": "{}",
+                "inputDetails": {"truncated": False},
+            },
+        },
+        {
+            "timestamp": datetime(2020, 1, 1, 0, 0, 10, tzinfo=tzlocal()),
+            "type": "ExecutionFailed",
+            "id": 3,
+            "previousEventId": 2,
+            "executionFailedEventDetails": {
+                "error": "AnError",
+                "cause": "An error occurred!",
+            },
+        },
+    ]
+
+    client = boto3.client("stepfunctions", region_name=region)
+    sm = client.create_state_machine(
+        name="test-state-machine",
+        definition=simple_definition,
+        roleArn=_get_default_role(),
+    )
+    execution = client.start_execution(stateMachineArn=sm["stateMachineArn"])
+    execution_history = client.get_execution_history(
+        executionArn=execution["executionArn"]
+    )
+    execution_history["events"].should.have.length_of(3)
+    execution_history["events"].should.equal(expected_events)
+
+
 @mock_stepfunctions
 @mock_cloudformation
 def test_state_machine_cloudformation():