Create API Gateway with Lambda Backend

stacks/src/template.py

@@ -1,18 +1,214 @@
-from troposphere import Template
+from awacs.aws import Action, Statement, Principal, Policy
+from troposphere import Template, GetAtt, Ref, Join, Output, iam, awslambda
+from troposphere.apigateway import RestApi, Resource, Method, Integration, IntegrationResponse, MethodResponse, \
+    Deployment, Stage
+from troposphere.awslambda import Function, Code
+from troposphere.s3 import Bucket
+from troposphere.sns import Topic, Subscription
 from troposphere.sqs import Queue
 
 from util import Util
 
 PROJECT_NAME: str = "Tweeter"
+REST_API_NAME: str = "TweeterAPI"
+REST_API_STAGE_NAME: str = "v1"
+API_LAMBDA_NAME: str = "ApiLambda"
+API_LAMBDA_KEBAB_NAME: str = "api-lambda"
+SHARED_CONFIG_BUCKET_NAME: str = "SharedConfig"
+
 S3_QUEUE_NAME: str = "S3Queue"
-TWEETER_QUEUE_NAME: str = "TwitterQueue"
+TWITTER_QUEUE_NAME: str = "TwitterQueue"
 DYNAMO_DB_QUEUE_NAME: str = "DynamoDbQueue"
+FANOUT_TOPIC_NAME: str = "FanoutTopic"
 
 template: Template = Template(PROJECT_NAME + "Workflow")
 templateUtil: Util = Util(template)
 
+shared_config_bucket: Bucket = template.add_resource(Bucket(SHARED_CONFIG_BUCKET_NAME))
+rest_api: RestApi = template.add_resource(RestApi(REST_API_NAME, Name=REST_API_NAME))
+
+api_lambda_execute_statements = [
+    Statement(
+        Action=[
+            Action("logs", "*"),
+            Action("cloudwatch", "*"),
+            Action("cloudformation", "DescribeStacks"),
+            Action("cloudformation", "DescribeStackEvents"),
+            Action("cloudformation", "DescribeStackResource"),
+            Action("cloudformation", "DescribeStackResources"),
+            Action("cloudformation", "GetTemplate"),
+            Action("cloudformation", "List*"),
+        ],
+        Effect="Allow",
+        Resource=["*"]
+    ),
+    Statement(
+        Action=[
+            Action("sns", "Publish")
+        ],
+        Effect="Allow",
+        Resource=[Ref(FANOUT_TOPIC_NAME)]
+    ),
+]
+
+
+api_lambda_execute_role: iam.Role = template.add_resource(
+    iam.Role(
+        API_LAMBDA_NAME + "ExecuteRole",
+        AssumeRolePolicyDocument=Policy(
+            Statement=[
+                Statement(
+                    Effect="Allow",
+                    Action=[Action("sts", "AssumeRole")],
+                    Principal=Principal("Service", ["lambda.amazonaws.com", "apigateway.amazonaws.com"])
+                )
+            ]
+        ),
+        Policies=[
+            iam.Policy(
+                PolicyName=API_LAMBDA_NAME + "ExecutePolicy",
+                PolicyDocument=Policy(Statement=api_lambda_execute_statements)
+            )
+        ]
+    )
+)
+
+api_lambda_code: Code = Code(
+    S3Bucket=Ref(shared_config_bucket),
+    S3Key=Join("", [API_LAMBDA_KEBAB_NAME, "/code/", API_LAMBDA_KEBAB_NAME, "-", "1", ".zip"])
+)
+
+api_lambda: Function = template.add_resource(
+    Function(
+        API_LAMBDA_NAME + "Function",
+        Code=api_lambda_code,
+        Description=API_LAMBDA_NAME + " Function",
+        Handler="request_handler.event_handler",
+        Role=GetAtt(API_LAMBDA_NAME + "ExecuteRole", "Arn"),
+        Runtime="python3.9",
+        Timeout=300,
+        MemorySize=1024
+    )
+)
+
+api_lambda_invoke_permission = template.add_resource(awslambda.Permission(
+    "APILambdaPermission",
+    Action="lambda:InvokeFunction",
+    FunctionName=Ref(api_lambda),
+    Principal="apigateway.amazonaws.com",
+    SourceArn=Join("", ["arn:aws:execute-api:", Ref("AWS::Region"), ":", Ref("AWS::AccountId"), ":", Ref(rest_api), "/*/*/*"])
+))
+
+rest_api_resource: Resource = template.add_resource(
+    Resource(
+        API_LAMBDA_NAME + "Resource",
+        RestApiId=Ref(rest_api),
+        PathPart="tweet",
+        ParentId=GetAtt(REST_API_NAME, "RootResourceId")
+    )
+)
+
+api_lambda_method: Method = template.add_resource(
+    Method(
+        API_LAMBDA_NAME + "Method",
+        DependsOn=API_LAMBDA_NAME + "Function",
+        RestApiId=Ref(rest_api),
+        AuthorizationType="NONE",
+        ResourceId=Ref(rest_api_resource),
+        HttpMethod="POST",
+        Integration=Integration(
+            Type="AWS",
+            IntegrationHttpMethod="POST",
+            IntegrationResponses=[IntegrationResponse(StatusCode="200")],
+            Uri=Join(
+                "",
+                [
+                    "arn:aws:apigateway:eu-west-1:lambda:path/2015-03-31/functions/",
+                    GetAtt(api_lambda, "Arn"),
+                    "/invocations"
+                ]
+            )
+        ),
+        MethodResponses=[MethodResponse("SuccessResponse", StatusCode="200")]
+    )
+)
+
+rest_api_deployment: Deployment = template.add_resource(
+    Deployment(
+        REST_API_STAGE_NAME + "Deployment",
+        DependsOn=API_LAMBDA_NAME + "Method",
+        RestApiId=Ref(rest_api)
+    )
+)
+
+rest_api_stage: Stage = template.add_resource(
+    Stage(
+        REST_API_STAGE_NAME + "Stage",
+        StageName=REST_API_STAGE_NAME,
+        RestApiId=Ref(rest_api),
+        DeploymentId=Ref(rest_api_deployment)
+    )
+)
+
+template.add_output(
+    [
+        Output(
+            "RestApiEndpoint",
+            Value=Join(
+                "",
+                [
+                    "https://",
+                    Ref(rest_api),
+                    ".execute-api.eu-west-1.amazonaws.com/",
+                    REST_API_STAGE_NAME,
+                ],
+            ),
+            Description="Endpoint for this stage of the api",
+        )
+    ]
+)
+
 s3_queue: Queue = templateUtil.create_queue(S3_QUEUE_NAME)
-tweeter_queue: Queue = templateUtil.create_queue(TWEETER_QUEUE_NAME)
+twitter_queue: Queue = templateUtil.create_queue(TWITTER_QUEUE_NAME)
 dynamo_db_queue: Queue = templateUtil.create_queue(DYNAMO_DB_QUEUE_NAME)
 
+fanout_topic: Topic = template.add_resource(Topic(
+    FANOUT_TOPIC_NAME,
+    Subscription=[
+        Subscription(
+            Protocol="sqs",
+            Endpoint=GetAtt(s3_queue, "Arn")
+        ),
+        Subscription(
+            Protocol="sqs",
+            Endpoint=GetAtt(twitter_queue, "Arn")
+        ),
+        Subscription(
+            Protocol="sqs",
+            Endpoint=GetAtt(dynamo_db_queue, "Arn")
+        )
+    ]
+))
+
+templateUtil.add_queue_policy_for_write_to_topic(
+    s3_queue,
+    "S3QueuePolicy",
+    "AllowS3QueueToWriteToFanoutTopic",
+    fanout_topic
+)
+
+templateUtil.add_queue_policy_for_write_to_topic(
+    twitter_queue,
+    "TwitterQueuePolicy",
+    "AllowTwitterQueueToWriteToFanoutTopic",
+    fanout_topic
+)
+
+templateUtil.add_queue_policy_for_write_to_topic(
+    dynamo_db_queue,
+    "DynamoDbQueuePolicy",
+    "AllowDynamoDbQueueToWriteToFanoutTopic",
+    fanout_topic
+)
+
 print(template.to_json())