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lambroll is a simple deployment tool for AWS Lambda.

lambroll does,

  • Create a function.
  • Create a Zip archive from local directory.
  • Deploy function code / configuration / tags / aliases / function URLs.
  • Rollback a function to previous version.
  • Invoke a function with payloads.
  • Manage function versions.
  • Show status of a function.
  • Show function logs.
  • Show diff of function code / configuration.
  • Delete a function.

lambroll does not,

  • Manage resources related to the Lambda function.
    • For example, IAM Role, function triggers, API Gateway, and etc.
    • Only the function URLs can be managed by lambroll if you want.
  • Build native binaries or extensions for Linux (AWS Lambda running environment).

When you hope to manage these resources, we recommend other deployment tools (AWS SAM, Serverless Framework, etc.).

Differences of lambroll v0 and v1.

See docs/


Homebrew (macOS and Linux)

$ brew install fujiwara/tap/lambroll


aqua is a declarative CLI Version Manager.

$ aqua g -i fujiwara/lambroll

Binary packages


CircleCI Orb

version: 2.1
  lambroll: fujiwara/lambroll@2.0.1
      - image: cimg/base
      - checkout
      - lambroll/install:
          version: v1.0.1
      - run:
          command: |
            lambroll deploy

GitHub Actions

Action fujiwara/lambroll@v0 installs lambroll binary for Linux into /usr/local/bin. This action runs install only.

    runs-on: ubuntu-latest
      - uses: actions/checkout@v4
      - uses: fujiwara/lambroll@v1
          version: v1.0.1
      - run: |
          lambroll deploy

Quick start

Try migrate your existing Lambda function hello.

$ mkdir hello
$ cd hello
$ lambroll init --function-name hello --download
2019/10/26 01:19:23 [info] function hello found
2019/10/26 01:19:23 [info] downloading
2019/10/26 01:19:23 [info] creating function.json
2019/10/26 01:19:23 [info] completed

$ unzip -l
  Length      Date    Time    Name
---------  ---------- -----   ----
      408  10-26-2019 00:30   index.js
---------                     -------
      408                     1 file

$ unzip
 extracting: index.js

$ rm

See or edit function.json or index.js.

Now you can deploy hello function using lambroll deploy.

$ lambroll deploy
2019/10/26 01:24:52 [info] starting deploy function hello
2019/10/26 01:24:53 [info] creating zip archive from .
2019/10/26 01:24:53 [info] zip archive wrote 1042 bytes
2019/10/26 01:24:53 [info] updating function configuration
2019/10/26 01:24:53 [info] updating function code hello
2019/10/26 01:24:53 [info] completed


Usage: lambroll <command>

  -h, --help                              Show context-sensitive help.
      --function=STRING                   Function file path ($LAMBROLL_FUNCTION)
      --log-level="info"                  log level (trace, debug, info, warn, error) ($LAMBROLL_LOGLEVEL)
      --color                             enable colored output ($LAMBROLL_COLOR)
      --region=REGION                     AWS region ($AWS_REGION)
      --profile=PROFILE                   AWS credential profile name ($AWS_PROFILE)
      --tfstate=TFSTATE                   URL to terraform.tfstate ($LAMBROLL_TFSTATE)
      --prefixed-tfstate=KEY=VALUE;...    key value pair of the prefix for template function name and URL to
                                          terraform.tfstate ($LAMBROLL_PREFIXED_TFSTATE)
      --endpoint=ENDPOINT                 AWS API Lambda Endpoint ($AWS_LAMBDA_ENDPOINT)
      --envfile=ENVFILE,...               environment files ($LAMBROLL_ENVFILE)
      --ext-str=KEY=VALUE;...             external string values for Jsonnet ($LAMBROLL_EXTSTR)
      --ext-code=KEY=VALUE;...            external code values for Jsonnet ($LAMBROLL_EXTCODE)

    deploy or create function

  init --function-name=
    init function.json

    list functions

    rollback function

    invoke function

    archive function

    show logs of function

    show diff of function

    render function.json

    show status of function

    delete function

    show versions of function

    show version

Run "lambroll <command> --help" for more information on a command.


lambroll init initialize function.json by existing function.

Usage: lambroll init --function-name=

init function.json

      --function-name=                    Function name for init
      --download                          Download
      --jsonnet                           render function.json as jsonnet
      --qualifier=QUALIFIER               function version or alias
      --function-url                      create function url definition file

init creates function.json as a configuration file of the function.


Usage: lambroll deploy

deploy or create function

      --src="."                           function zip archive or src dir
      --publish                           publish function
      --alias="current"                   alias name for publish
      --alias-to-latest                   set alias to unpublished $LATEST version
      --dry-run                           dry run
      --skip-archive                      skip to create zip archive. requires Code.S3Bucket and Code.S3Key in function
      --keep-versions=0                   Number of latest versions to keep. Older versions will be deleted. (Optional
                                          value: default 0).
      --function-url=""                   path to function-url definition
      --skip-function                     skip to deploy a function. deploy function-url only
      --exclude-file=".lambdaignore"      exclude file

deploy works as below.

  • Create a zip archive from --src directory.
    • Excludes files matched (wildcard pattern) in --exclude-file.
  • Create / Update Lambda function
  • Create an alias to the published version when --publish (default).

Deploy container image

lambroll also support to deploy a container image for Lambda.

PackageType=Image and Code.ImageUri are required in function.json. ImageConfig is optional.

  "FunctionName": "container",
  "MemorySize": 128,
  "Role": "arn:aws:iam::012345678912:role/test_lambda_function",
  "PackageType": "Image",
  "Code": {
    "ImageUri": ""
  "ImageConfig": {
    "Command": [
    "WorkingDirectory": "/var/task",
    "EntryPoint": [


Usage: lambroll rollback

rollback function

      --dry-run                   dry run
      --alias="current"           alias to rollback
      --version=""                version to rollback (default: previous version auto detected)
      --delete-version            delete rolled back version

lambroll deploy create/update alias to the published function version on deploy.

lambroll rollback works as below.

  1. Find the previous version from the alias with no other aliases.
  2. Update the alias to the previous version.
    • If --version is specified, update the alias to the specified version.
  3. When --delete-version is specified, delete the old version of the function.

If you add multiple aliases to the function, lambroll rollback --alias={some-alias} may not work as expected. Because the previous version that auto-detected may be the older version of other aliases.

So you should specify the version to rollback with --version flag to clear the ambiguity.


Usage: lambroll invoke

invoke function

      --async                             invocation type async
      --log-tail                          output tail of log to STDERR
      --qualifier=QUALIFIER               version or alias to invoke
      --payload=PAYLOAD                   payload to invoke. if not specified, read from STDIN

lambroll invoke accepts multiple JSON payloads for invocations from --payload flag or STDIN.

If the payload is a concatenation of multiple JSON payloads, lambroll invoke will invoke the function for each JSON payload.

Outputs from the function invoked are printed to STDOUT.

$ lambroll invoke --payload='{"foo":1} --log-tail'
{"success": true, "payload": {"foo":1}}
2019/10/28 23:16:43 [info] StatusCode:200 ExecutionVersion:$LATEST
START RequestId: aa38233f-a179-4192-8469-c86414fe463c Version: $LATEST
END RequestId: aa38233f-a179-4192-8469-c86414fe463c
REPORT RequestId: 60140e16-018e-41b1-bb46-3f021d4960c0	Duration: 561.77 ms	Billed Duration: 600 ms	Memory Size: 128 MB	Max Memory Used: 50 MB

$ echo '{"foo":1}{"foo":2}' | lambroll invoke --log-tail
{"success": true, payload{"foo":1}}
2019/10/28 23:16:43 [info] StatusCode:200 ExecutionVersion:$LATEST
START RequestId: 60140e16-018e-41b1-bb46-3f021d4960c0 Version: $LATEST
END RequestId: 60140e16-018e-41b1-bb46-3f021d4960c0
REPORT RequestId: 60140e16-018e-41b1-bb46-3f021d4960c0	Duration: 561.77 ms	Billed Duration: 600 ms	Memory Size: 128 MB	Max Memory Used: 50 MB
{"success": true, payload:{"foo":2}}
2019/10/28 23:16:43 [info] StatusCode:200 ExecutionVersion:$LATEST
START RequestId: dcc584f5-ceaf-4109-b405-8e59ca7ae92f Version: $LATEST
END RequestId: dcc584f5-ceaf-4109-b405-8e59ca7ae92f
REPORT RequestId: dcc584f5-ceaf-4109-b405-8e59ca7ae92f	Duration: 597.87 ms	Billed Duration: 600 ms	Memory Size: 128 MB	Max Memory Used: 50 MB
2019/10/28 23:16:43 [info] completed


function.json is a definition for Lambda function. JSON structure is based from CreateFunction for Lambda API.

  "Architectures": [
  "Description": "hello function for {{ must_env `ENV` }}",
  "EphemeralStorage": {
    "Size": 1024
  "Environment": {
    "Variables": {
      "BAR": "baz",
      "FOO": "{{ env `FOO` `default for FOO` }}"
  "FunctionName": "{{ must_env `ENV` }}-hello",
  "FileSystemConfigs": [
      "Arn": "arn:aws:elasticfilesystem:ap-northeast-1:123456789012:access-point/fsap-04fc0858274e7dd9a",
      "LocalMountPath": "/mnt/lambda"
  "Handler": "index.js",
  "MemorySize": 128,
  "Role": "arn:aws:iam::123456789012:role/hello_lambda_function",
  "Runtime": "nodejs18.x",
  "Tags": {
    "Env": "dev"
  "Timeout": 5,
  "TracingConfig": {
    "Mode": "PassThrough"


When "Tags" key exists in function.json, lambroll set / remove tags to the lambda function at deploy.

  // ...
  "Tags": {
    "Env": "dev",
    "Foo": "Bar"

When "Tags" key does not exist, lambroll doesn't manage tags. If you hope to remove all tags, set "Tags": {} expressly.

Expand SSM parameter values

At reading the file, lambroll evaluates {{ ssm }} syntax in JSON.

For example,

{{ ssm `/path/to/param` }}

SSM parameter value of /path/to/param is expanded here.

Expand environment variables

At reading the file, lambroll evaluates {{ env }} and {{ must_env }} syntax in JSON.

For example,

{{ env `FOO` `default for FOO` }}

Environment variable FOO is expanded here. When FOO is not defined, use default value.

{{ must_env `FOO` }}

Environment variable FOO is expanded. When FOO is not defined, lambroll will panic and abort.

json_escape template function escapes JSON meta characters in string values. This is useful for inject structured values into environment variables.

    "Environment": {
        "Variables": {
            "JSON": "{{ env `JSON` | json_escape }}"

Environment variables from envfile

lambroll --envfile .env1 .env2 reads files named .env1 and .env2 as environment files and export variables in these files.

These files are parsed by hashicorp/go-envparse.

export BAR="bar"

Lookup resource attributes in tfstate (Terraform state)

When --tfstate option set to an URL to terraform.tfstate, tfstate template function enabled.

For example, define your AWS resources by terraform.

data "aws_iam_role" "lambda" {
  name = "hello_lambda_function"

terraform apply creates a terraform.tfstate file.

lambroll --tfstate URL ... enables to lookup resource attributes in the tfstate URL.

  "Description": "hello function",
  "FunctionName": "hello",
  "Handler": "index.js",
  "MemorySize": 128,
  "Role": "{{ tfstate `data.aws_iam_role.lambda.arn` }}",
  "Runtime": "nodejs12.x",
  "Timeout": 5,
  "TracingConfig": {
    "Mode": "PassThrough"
  "VpcConfig": {
    "SubnetIds": [
      "{{ tfstate `aws_subnet.lambda['az-a'].id` }}",
      "{{ tfstate `aws_subnet.lambda['az-b'].id` }}"
    "SecurityGroupIds": [
      "{{ tfstatef `aws_security_group.internal['%s'].id` (must_env `WORLD`) }}"

Likewise, if you have AWS resource definitions spread across multiple tfstate files, you can utilize --prefixed-tfstate option:


lambroll --prefixed-tfstate="my_first_=s3://my-bucket/first.tfstate" --prefixed-tfstate="my_second_=s3://my-bucket/second.tfstate" ...

which then exposes additional template functions available like:

  "Description": "hello function",
  "Environment": {
    "Variables": {
      "FIRST_VALUE": "{{ my_first_tfstate `data.aws_iam_role.lambda.arn` }}",
      "SECOND_VALUE": "{{ my_second_tfstate `data.aws_iam_role.lambda.arn` }}"
  "rest of the parameters": "..."

Jsonnet support for function configuration

lambroll also can read function.jsonnet as Jsonnet format instead of plain JSON.

  FunctionName: 'hello',
  Handler: 'index.handler',
  MemorySize: std.extVar('memorySize'),
  Role: 'arn:aws:iam::%s:role/lambda_role' % [ std.extVar('accountID') ],
  Runtime: 'nodejs20.x',
$ lambroll \
    --function function.jsonnet \
    --ext-str accountID=0123456789012 \
    --ext-code memorySize="128 * 4" \


lambroll will ignore files defined in .lambdaignore file at creating a zip archive.

For example,

# comment


For each line in .lambdaignore are evaluated as Go's path/filepath#Match.

Lambda@Edge support

lambroll can deploy Lambda@Edge functions.

Edge functions require two preconditions:

  • --region must set to us-east-1.
  • The IAM Role must be assumed by and both.

Otherwise, it works as usual.

Lambda function URLs support

lambroll can deploy Lambda function URLs.

lambroll deploy --function-url=function_url.json deploys a function URL after the function deploied.

Even if your Lambda function already has a function URL, lambroll deploy without --function-url option does not touch the function URLs resources.

When you want to deploy a public (without authentication) function URL, function_url.json is shown below.

  "Config": {
    "AuthType": "NONE"

When you want to deploy a private (requires AWS IAM authentication) function URL, function_url.json is shown below.

  "Config": {
    "AuthType": "AWS_IAM",
    "Cors": {
      "AllowOrigins": [
      "AllowMethods": [
  "Permissions": [
      "Principal": "0123456789012"
      "PrincipalOrgID": "o-123456789",
      "Principal": "*"
  • Config maps to CreateFunctionUrlConfigInput in AWS SDK Go v2.
    • Config.AuthType must be AWS_IAM or NONE.
    • Config.Qualifier is optional. Default is $LATEST.
  • Permissions is optional.
    • If Permissions is not defined and AuthType is NONE, Principal is set to * automatically.
    • When AuthType is AWS_IAM, you must define Permissions to specify allowed principals.
    • Each elements of Permissions maps to AddPermissionInput in AWS SDK Go v2.
  • function_url.jsonnet is also supported like function.jsonnet.

CloudFront origin access control (OAC) support

CloudFront provides origin access control (OAC) for restricting access to a Lambda function URL origin.

When you want to restrict access to a Lambda function URL origin by CloudFront, you can specify Principal as and SourceArn as the ARN of the CloudFront distribution.

See also Restricting access to an AWS Lambda function URL origin.

  "Config": {
    "AuthType": "AWS_IAM",
  "Permissions": [
      "Principal": "",
      "SourceArn": "arn:aws:cloudfront::123456789012:distribution/EXXXXXXXX"

If you need to allow access from any CloudFront distributions in your account, you can specify SourceArn as arn:aws:cloudfront::123456789012:distribution/*.

Specifying SourceArn as * is not recommended because it allows access from any CloudFront distribution in any AWS account.


MIT License

Copyright (c) 2019 FUJIWARA Shunichiro