### [Read this on the main serverless docs site](https://www.serverless.com/framework/docs/providers/aws/cli-reference/invoke-local) # AWS - Invoke Local This runs your code locally by emulating the AWS Lambda environment. Please keep in mind, it's not a 100% perfect emulation, there may be some differences, but it works for the vast majority of users. We mock the `context` with simple mock data. ```bash serverless invoke local --function functionName ``` ## Options - `--function` or `-f` The name of the function in your service that you want to invoke locally. **Required**. - `--path` or `-p` The path to a json file holding input data to be passed to the invoked function as the `event`. This path is relative to the root directory of the service. - `--data` or `-d` String data to be passed as an event to your function. Keep in mind that if you pass both `--path` and `--data`, the data included in the `--path` file will overwrite the data you passed with the `--data` flag. ## Environment The invoke local command sets reasonable environment variables for the invoked function. All AWS specific variables are set to values that are quite similar to those found in a real "physical" AWS Lambda environment. Additionally the `IS_LOCAL` variable is set, that allows you to determine a local execution within your code. ## Examples ### Local function invocation ```bash serverless invoke local --function functionName ``` This example will locally invoke your function. ### Local function invocation with data ```bash serverless invoke local --function functionName --data "hello world" ``` ```bash serverless invoke local --function functionName --data '{"a":"bar"}' ``` ### Local function invocation with data from standard input ```bash node dataGenerator.js | serverless invoke local --function functionName ``` ### Local function invocation with data passing ```bash serverless invoke local --function functionName --path lib/data.json ``` This example will pass the json data in the `lib/data.json` file (relative to the root of the service) while invoking the specified/deployed function. ### Example `data.json` ```json { "resource": "/", "path": "/", "httpMethod": "GET", // etc. // } ``` ### Limitations Currently, `invoke local` only supports the NodeJs and Python runtimes. ## Resource permissions Lambda functions assume an *IAM role* during execution: the framework creates this role, and set all the permission provided in the `iamRoleStatements` section of `serverless.yml`. Unless you explicitly state otherwise, every call to the AWS SDK inside the lambda function is made using this role (a temporary pair of key / secret is generated and set by AWS as environment variables, `AWS_ACCESS_KEY_ID` and `AWS_SECRET_ACCESS_KEY`). When you use `serverless invoke local`, the situation is quite different: the role isn't available (the function is executed on your local machine), so unless you set a different user directly in the code (or via a key pair of environment variables), the AWS SDK will use the default profile specified inside you AWS credential configuration file. Take a look to the official AWS documentation (in this particular instance, for the javascript SDK, but should be similar for all SDKs): - [http://docs.aws.amazon.com/sdk-for-javascript/v2/developer-guide/loading-node-credentials-shared.html](http://docs.aws.amazon.com/sdk-for-javascript/v2/developer-guide/loading-node-credentials-shared.html) - [http://docs.aws.amazon.com/sdk-for-javascript/v2/developer-guide/loading-node-credentials-lambda.html](http://docs.aws.amazon.com/sdk-for-javascript/v2/developer-guide/loading-node-credentials-lambda.html) Whatever approach you decide to implement, **be aware**: the set of permissions might be (and probably is) different, so you won't have an exact simulation of the *real* IAM policy in place.