Introduction to testing with sam local generate-event

To see a list of supported Amazon Web Services

1. Run the following:

   $ sam local generate-event

2. The list of supported Amazon Web Services will display. The following is an example:

   $ sam local generate-event
   ...
   Commands:
     alb
     alexa-skills-kit
     alexa-smart-home
     apigateway
     appsync
     batch
     cloudformation
     ...

To generate a local event

1. Run sam local generate-event and provide the supported service name. This will display a list of event types that you can generate. The following is an example:

   $ sam local generate-event s3
   
   Usage: sam local generate-event s3 [OPTIONS] COMMAND [ARGS]...
   
   Options:
     -h, --help  Show this message and exit.
   
   Commands:
     batch-invocation  Generates an Amazon S3 Batch Operations Invocation Event
     delete            Generates an Amazon S3 Delete Event
     put               Generates an Amazon S3 Put Event

2. To generate the sample event, run sam local generate-event, providing the service and event type.

   $ sam local generate-event <service> <event>

   The following is an example:

   $ sam local generate-event s3 put
   {
     "Records": [
       {
         "eventVersion": "2.0",
         "eventSource": "aws:s3",
         "awsRegion": "us-east-1",
         "eventTime": "1970-01-01T00:00:00.000Z",
         "eventName": "ObjectCreated:Put",
         "userIdentity": {
           "principalId": "EXAMPLE"
         },
         "requestParameters": {
           "sourceIPAddress": "127.0.0.1"
         },
         "responseElements": {
           "x-amz-request-id": "EXAMPLE123456789",
           "x-amz-id-2": "EXAMPLE123/5678abcdefghijklambdaisawesome/mnopqrstuvwxyzABCDEFGH"
         },
         "s3": {
           "s3SchemaVersion": "1.0",
           "configurationId": "testConfigRule",
           "bucket": {
             "name": "example-bucket",
             "ownerIdentity": {
               "principalId": "EXAMPLE"
             },
             "arn": "arn:aws:s3:::example-bucket"
           },
           "object": {
             "key": "test/key",
             "size": 1024,
             "eTag": "0123456789abcdef0123456789abcdef",
             "sequencer": "0A1B2C3D4E5F678901"
           }
         }
       }
     ]
   }

To modify a sample event

1. You can modify sample events at the command prompt. To see your options, run the following:

   $ sam local generate-event <service> <event> --help

   The following is an example:

   $ sam local generate-event s3 put --help
   
   Usage: sam local generate-event s3 put [OPTIONS]
   
   Options:
     --region TEXT       Specify the region name you'd like, otherwise the
                         default = us-east-1
     --partition TEXT    Specify the partition name you'd like, otherwise the
                         default = aws
     --bucket TEXT       Specify the bucket name you'd like, otherwise the
                         default = example-bucket
     --key TEXT          Specify the key name you'd like, otherwise the default =
                         test/key
     --debug             Turn on debug logging to print debug message generated
                         by AWS SAM CLI and display timestamps.
     --config-file TEXT  Configuration file containing default parameter values.
                         [default: samconfig.toml]
     --config-env TEXT   Environment name specifying default parameter values in
                         the configuration file.  [default: default]
     -h, --help          Show this message and exit.

2. Use any of these options at the command prompt to modify your sample event payload. The following is an example:

   $ sam local generate-event s3 put--bucket MyBucket
   
   {
     "Records": [
       {
         "eventVersion": "2.0",
         "eventSource": "aws:s3",
         "awsRegion": "us-east-1",
         "eventTime": "1970-01-01T00:00:00.000Z",
         "eventName": "ObjectCreated:Put",
         "userIdentity": {
           "principalId": "EXAMPLE"
         },
         "requestParameters": {
           "sourceIPAddress": "127.0.0.1"
         },
         "responseElements": {
           "x-amz-request-id": "EXAMPLE123456789",
           "x-amz-id-2": "EXAMPLE123/5678abcdefghijklambdaisawesome/mnopqrstuvwxyzABCDEFGH"
         },
         "s3": {
           "s3SchemaVersion": "1.0",
           "configurationId": "testConfigRule",
           "bucket": {
             "name": "MyBucket",
             "ownerIdentity": {
               "principalId": "EXAMPLE"
             },
             "arn": "arn:aws:s3:::MyBucket"
           },
           "object": {
             "key": "test/key",
             "size": 1024,
             "eTag": "0123456789abcdef0123456789abcdef",
             "sequencer": "0A1B2C3D4E5F678901"
           }
         }
       }
     ]
   }

To save your generated events locally

• Run the following:

  $ sam local generate-event <service> <event> <event-option> > <filename.json>

  The following is an example of an event being saved as an s3.json file in the events folder of our project.

  sam-app$ sam local generate-event s3 put --bucket MyBucket > events/s3.json

To use a generated event for local testing

• Pass the event with other sam local subcommands by using the --event option.

  The following is an example of using the s3.json event to invoke our Lambda function locally:

  sam-app$ sam local invoke --event events/s3.json S3JsonLoggerFunction
  
  Invoking src/handlers/s3-json-logger.s3JsonLoggerHandler (nodejs18.x)
  Local image is up-to-date
  Using local image: public.ecr.aws/lambda/nodejs:18-rapid-x86_64.
  
  Mounting /Users/.../sam-app/.aws-sam/build/S3JsonLoggerFunction as /var/task:ro,delegated, inside runtime container
  START RequestId: f4f45b6d-2ec6-4235-bc7b-495ec2ae0128 Version: $LATEST
  END RequestId: f4f45b6d-2ec6-4235-bc7b-495ec2ae0128
  REPORT RequestId: f4f45b6d-2ec6-4235-bc7b-495ec2ae0128  Init Duration: 1.23 ms  Duration: 9371.93 ms      Billed Duration: 9372 ms        Memory Size: 128 MB     Max Memory Used: 128 MB