List Lambda Functions and Lambda Layers with the AWS CLI

Here are a few helper functions to list Lambda functions and layers (and to count them) using the AWS Command Line Interface (AWS CLI) to inspect the serverless resources of your Amazon Web Services (AWS) account.

Listing Lambda Layers of a Function

aws lambda get-function --function-name {name|arn} | \
jq .Configuration.Layers

[
  {
    "Arn": "arn:aws:lambda:us-west-2:00000000:layer:layer-name:1",
    "CodeSize": 1231231
  }
]

Counting Lambda Layers of a Function

aws lambda get-function --function-name {name|arn} | \
jq '.Configuration.Layers | length'

# Returns 1 (or number of layers attached to function)

Counting Lambda Layers in an AWS account

aws lambda list-layers | \
jq '.Layers | length'

# Returns 4 (or number of layers in your account)

Listing All Layers in an AWS account

aws lambda list-layers

{
    "Layers": [
        {
            "LayerName": "layer-name",
            "LayerArn": "arn:aws:lambda:us-west-2:0123456789:layer:layer-name",
            "LatestMatchingVersion": {
                "LayerVersionArn": "arn:aws:lambda:us-west-2:0123456789:layer:layer-name:1",
                "Version": 1,
                "Description": "Layer Description",
                "CreatedDate": "2021-07-14T14:00:27.370+0000",
                "CompatibleRuntimes": [
                    "python3.7"
                ],
                "LicenseInfo": "MIT"
            }
        },
        {
            "LayerName": "another-layer-name",
            "LayerArn": "arn:aws:lambda:us-west-2:0123456789:layer:another-layer-name",
            "LatestMatchingVersion": {
                "LayerVersionArn": "arn:aws:lambda:us-west-2:0123456789:layer:another-layer-name:4",
                "Version": 4,
                "Description": "Layer Description",
                "CreatedDate": "2021-07-14T11:41:45.520+0000",
                "CompatibleRuntimes": [
                    "python3.6"
                ],
                "LicenseInfo": "MIT"
            }
        }
    ]
}

Listing Lambda Functions in an AWS account

aws lambda list-functions

{
    "Functions": [
        {
            "FunctionName": "function-name",
            "FunctionArn": "arn:aws:lambda:us-west-2:0123456789:function:function-name",
            "Runtime": "python3.7",
            "Role": "arn:aws:iam::0123456789:role/role-name",
            "Handler": "lambda_function.lambda_handler",
            "CodeSize": 1234,
            "Description": "Function description.",
            "Timeout": 30,
            "MemorySize": 128,
            "LastModified": "2021-07-14T16:48:19.052+0000",
            "CodeSha256": "28ua8s0aw0820492r=",
            "Version": "$LATEST",
            "Environment": {
                "Variables": {
                }
            },
            "TracingConfig": {
                "Mode": "PassThrough"
            },
            "RevisionId": "1b0be4c3-4eb6-4254-9061-050702646940",
            "Layers": [
                {
                    "Arn": "arn:aws:lambda:us-west-2:0123456789:layer:layer-name:1",
                    "CodeSize": 1563937
                }
            ],
            "PackageType": "Zip"
        }
    ]
}