npm package: @lendi/serverless-simplify-default-exec-role-plugin
Description: serverless-simplify-default-exec-role-plugin
Author: Lendi Engineering
Latest version: 1.0.0

# serverless-simplify-default-exec-role-plugin

** This is a fork of [serverless-simplify-default-exec-role-plugin](https://github.com/woebot/serverless-simplify-default-exec-role-plugin) by [woebot](https://github.com/woebot)

which in itself was a fork of [serverless-simplify-default-exec-role-plugin](https://github.com/shelfio/serverless-simplify-default-exec-role-plugin) by [shelfio](https://github.com/shelfio) **

A quick solution for the `IamRoleLambdaExecution` error: `Maximum policy size of 10240 bytes exceeded`.

- This plugin modifies the `IamRoleLambdaExecution` policy to reduce its size.  
- Unlike the [original version](https://www.npmjs.com/package/@shelf/serverless-simplify-default-exec-role-plugin), this maintains any custom IAM statements attached to the Lambda role. 
- It also doesn't collapse `"logs:CreateLogStream"`, `"logs:CreateLogGroup"`, and `"logs:PutLogEvents"` permissions into the same IAM statement.

## Installation

```
$ npm install --dev @lendi/serverless-simplify-default-exec-role-plugin
```

## Usage

In your `serverless.yml` file:

```yaml
plugins:
  - "@lendi/serverless-simplify-default-exec-role-plugin"
```

## IAM simplification for `logs:` statements

By default the Serverless framework adds something like the IAM statement below in order to allow write access to CloudWatch log groups that are part of the deployment stack. For stacks with a lot of lambda functions, this can cause the role to exceed the maximum allowed size of 10240 bytes. This plugin reduces the size of the generated lambda role by replacing the resource list with a single ARN to grants write access to _all_ log groups that are part of the same region and account.

### Before
```json5
{
  "Effect": "Allow",
  "Action": ["logs:CreateLogStream", "logs:CreateLogGroup"],
  "Resource": [
    {
      "Fn::Sub": "arn:${AWS::Partition}:logs:${AWS::Region}:${AWS::AccountId}:log-group:/aws/lambda/production-users-createUser:*",
    },
    {
      "Fn::Sub": "arn:${AWS::Partition}:logs:${AWS::Region}:${AWS::AccountId}:log-group:/aws/lambda/production-users-updateUser:*",
    },
    {
      "Fn::Sub": "arn:${AWS::Partition}:logs:${AWS::Region}:${AWS::AccountId}:log-group:/aws/lambda/production-users-deleteUser:*",
    },
    // ... and so on, for each lambda function that logs to cloudwatch
  ],
}
```

### After

```json5
{
  "Effect": "Allow",
  "Action": ["logs:CreateLogStream", "logs:CreateLogGroup"],
  "Resource": [
    {
      "Fn::Sub": "arn:${AWS::Partition}:logs:${AWS::Region}:${AWS::AccountId}:log-group:*",
    },
  ],
}
```

## IAM simplification for `kinesis:*` statements

**Needs more testing**

When you attach a kinesis stream as an event source, it creates an IAM policy per kinesis stream

### Before
```json5
{
    "Effect": "Allow",
    "Action": [
        "kinesis:GetRecords",
        "kinesis:GetShardIterator",
        "kinesis:DescribeStreamSummary",
        "kinesis:ListShards"
    ],
    "Resource": [
        "arn:aws:kinesis:<region>:<account>:stream/<stream-name>"
    ]
},
...many depending on number of input events to lambdas
{
    "Effect": "Allow",
    "Action": [
        "kinesis:GetRecords",
        "kinesis:GetShardIterator",
        "kinesis:DescribeStreamSummary",
        "kinesis:ListShards"
    ],
    "Resource": [
        "arn:aws:kinesis:<region>:<account>:stream/<stream-name>"
    ]
},
```

### After

```json5
{
    "Effect": "Allow",
    "Action": [
        "kinesis:GetRecords",
        "kinesis:GetShardIterator",
        "kinesis:DescribeStreamSummary",
        "kinesis:ListShards"
    ],
    "Resource": [
        "arn:aws:kinesis:<region>:<account>:stream/<stream-name>"
    ]
},
```

## tests

We have every intention of creating more tests to validate this plugin...

## License

MIT ©