/localstack

💻 A fully functional local AWS cloud stack. Develop and test your cloud & Serverless apps offline!

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LocalStack - A fully functional local AWS cloud stack

LocalStack

LocalStack provides an easy-to-use test/mocking framework for developing Cloud applications.

Currently, the focus is primarily on supporting the AWS cloud stack.

Announcements

  • 2019-10-09: LocalStack Pro is out! We're incredibly excited to announce the launch of LocalStack Pro - the enterprise version of LocalStack with additional APIs and advanced features. Check out the free trial at https://localstack.cloud
  • 2018-01-10: Help wanted! Please fill out this survey to support a research study on the usage of Serverless and Function-as-a-Service (FaaS) services, conducted at the Chalmers University of Technology. The survey only takes 5-10 minutes of your time. Many thanks for your participation!!
    • The result from this study can be found here
  • 2017-08-27: We need your support! LocalStack is growing fast, we now have thousands of developers using the platform regularly. Last month we have recorded a staggering 100k test runs, with 25k+ DynamoDB tables, 20k+ SQS queues, 15k+ Kinesis streams, 13k+ S3 buckets, and 10k+ Lambda functions created locally - for 0$ costs (more details to be published soon). Bug and feature requests are pouring in, and we now need some support from you to keep the open-source version actively maintained. Please check out Open Collective and become a backer or supporter of the project today! Thanks, everybody for contributing. ♥
  • 2017-07-20: Please note: Starting with version 0.7.0, the Docker image will be pushed and kept up to date under the new name localstack/localstack. (This means that you may have to update your CI configurations.) Please refer to the updated End-User License Agreement (EULA) for the new versions. The old Docker image (atlassianlabs/localstack) is still available but will not be maintained any longer.

Overview

LocalStack spins up the following core Cloud APIs on your local machine.

Note: Starting with version 0.11.0, all APIs are exposed via a single edge service, which is accessible on http://localhost:4566 by default (customizable via EDGE_PORT, see further below). The API-specific endpoints below are still left for backward-compatibility but may get removed in a future release - please reconfigure your client SDKs to start using the single edge endpoint URL!

In addition to the above, the Pro version of LocalStack supports additional APIs and advanced features, including:

  • API Gateway V2 (WebSockets support)
  • AppSync
  • Athena
  • CloudFront
  • CloudTrail
  • Cognito
  • ECS/EKS
  • ElastiCache
  • EMR
  • Glacier / S3 Select
  • IoT
  • Lambda Layers
  • MediaStore
  • QLDB
  • RDS
  • Transfer
  • XRay
  • Interactive UIs to manage resources
  • Test report dashboards
  • ...and much, much more to come!

Why LocalStack?

LocalStack builds on existing best-of-breed mocking/testing tools, notably kinesalite/dynalite and moto, ElasticMQ, and others. While these tools are awesome (!), they lack functionality for certain use cases. LocalStack combines the tools, makes them interoperable, and adds important missing functionality on top of them:

  • Error injection: LocalStack allows to inject errors frequently occurring in real Cloud environments, for instance ProvisionedThroughputExceededException which is thrown by Kinesis or DynamoDB if the amount of read/write throughput is exceeded.
  • Isolated processes: Services in LocalStack can be run in separate processes. The overhead of additional processes is acceptable, and the entire stack can easily be executed on any developer machine and CI server. In moto, components are often hard-wired in memory (e.g., when forwarding a message on an SNS topic to an SQS queue, the queue endpoint is looked up in a local hash map). In contrast, LocalStack services live in isolation (separate processes communicating via HTTP), which fosters true decoupling and more closely resembles the real cloud environment.
  • Pluggable services: All services in LocalStack are easily pluggable (and replaceable), due to the fact that we are using isolated processes for each service. This allows us to keep the framework up-to-date and select best-of-breed mocks for each individual service.

Requirements

  • python (both Python 2.x and 3.x supported)
  • pip (python package manager)
  • Docker

Installing

The easiest way to install LocalStack is via pip:

pip install localstack

Note: Please do not use sudo or the root user - LocalStack should be installed and started entirely under a local non-root user. If you have problems with permissions in MacOS X Sierra, install with pip install --user localstack

Running in Docker

By default, LocalStack gets started inside a Docker container using this command:

localstack start

(Note that on MacOS you may have to run TMPDIR=/private$TMPDIR localstack start --docker if $TMPDIR contains a symbolic link that cannot be mounted by Docker.)

Note: Instead of using the default Docker image (localstack/localstack), you may also choose the more light-weight image localstack/localstack-light which has some large dependency files like Elasticsearch removed (and lazily downloads them, if requested). Please refer to the USE_LIGHT_IMAGE configuration below (note that the light version may become the default in the future).

Using docker-compose

You can also use the docker-compose.yml file from the repository and use this command (currently requires docker-compose version 2.1+):

docker-compose up

(Note that on MacOS you may have to run TMPDIR=/private$TMPDIR docker-compose up if $TMPDIR contains a symbolic link that cannot be mounted by Docker.)

To facilitate interoperability, configuration variables can be prefixed with LOCALSTACK_ in docker. For instance, setting LOCALSTACK_SERVICES=s3 is equivalent to SERVICES=s3.

Starting locally (non-Docker mode)

Alternatively, the infrastructure can be spun up on the local host machine (without using Docker) using the following command:

localstack start --host

(Note that this will require additional dependencies, and currently is not supported on some operating systems, including Windows.)

LocalStack will attempt to automatically fetch the missing dependencies when you first start it up in "host" mode; alternatively, you can use the full profile to install all dependencies at pip installation time:

pip install "localstack[full]"

Configurations

You can pass the following environment variables to LocalStack:

  • EDGE_PORT: Port number for the edge service, the main entry point for all API invocations (default: 4566).

  • SERVICES: Comma-separated list of service names (APIs) to start up. Service names basically correspond to the service names of the AWS CLI (kinesis, lambda, sqs, etc), although LocalStack only supports a subset of them. Example value: kinesis,lambda,sqs to start Kinesis, Lambda, and SQS. In addition, the following shorthand values can be specified to run a predefined ensemble of services:

    • serverless: run services often used for Serverless apps (iam, lambda, dynamodb, apigateway, s3, sns)

  • DEFAULT_REGION: AWS region to use when talking to the API (default: us-east-1).

  • HOSTNAME: Name of the host to expose the services internally (default: localhost). Use this to customize the framework-internal communication, e.g., if services are started in different containers using docker-compose.

  • HOSTNAME_EXTERNAL: Name of the host to expose the services externally (default: localhost). This host is used, e.g., when returning queue URLs from the SQS service to the client.

  • <SERVICE>_PORT: Port number to bind a specific service to (defaults to service ports above).

  • <SERVICE>_PORT_EXTERNAL: Port number to expose a specific service externally (defaults to service ports above). SQS_PORT_EXTERNAL, for example, is used when returning queue URLs from the SQS service to the client.

  • USE_SSL: Whether to use https://... URLs with SSL encryption (default: false).

  • IMAGE_NAME: Specific name and tag of LocalStack Docker image to use, e.g., localstack/localstack:0.11.0 (default: localstack/localstack).

  • USE_LIGHT_IMAGE: Whether to use the light-weight Docker image (default: 0). Overwritten by IMAGE_NAME.

  • KINESIS_ERROR_PROBABILITY: Decimal value between 0.0 (default) and 1.0 to randomly inject ProvisionedThroughputExceededException errors into Kinesis API responses.

  • KINESIS_SHARD_LIMIT: Integer value (default: 100) or Infinity (to disable), causing the Kinesis API to start throwing exceptions to mimick the default shard limit.

  • KINESIS_LATENCY: Integer value (default: 500) or 0 (to disable), causing the Kinesis API to delay returning a response in order to mimick latency from a live AWS call.

  • DYNAMODB_ERROR_PROBABILITY: Decimal value between 0.0 (default) and 1.0 to randomly inject ProvisionedThroughputExceededException errors into DynamoDB API responses.

  • STEPFUNCTIONS_LAMBDA_ENDPOINT: URL to use as the lambda service endpoint in step functions. By default this is the localstack lambda endpoint.

  • LAMBDA_EXECUTOR: Method to use for executing Lambda functions. Possible values are:

    • local: run Lambda functions in a temporary directory on the local machine
    • docker: run each function invocation in a separate Docker container
    • docker-reuse: create one Docker container per function and reuse it across invocations

    For docker and docker-reuse, if LocalStack itself is started inside Docker, then the docker command needs to be available inside the container (usually requires to run the container in privileged mode). Default is docker, fallback to local if Docker is not available.

  • LAMBDA_REMOTE_DOCKER determines whether Lambda code is copied or mounted into containers. Possible values are:

    • true (default): your Lambda function definitions will be passed to the container by copying the zip file (potentially slower). It allows for remote execution, where the host and the client are not on the same machine.
    • false: your Lambda function definitions will be passed to the container by mounting a volume (potentially faster). This requires to have the Docker client and the Docker host on the same machine.

  • LAMBDA_DOCKER_NETWORK: Optional Docker network for the container running your lambda function.

  • LAMBDA_CONTAINER_REGISTRY Use an alternative docker registry to pull lambda execution containers (default: lambci/lambda).

  • LAMBDA_REMOVE_CONTAINERS: Whether to remove containers after Lambdas finished executing (default: true).

  • DATA_DIR: Local directory for saving persistent data (currently only supported for these services: Kinesis, DynamoDB, Elasticsearch, S3, Secretsmanager, SSM, SQS, SNS). Set it to /tmp/localstack/data to enable persistence (/tmp/localstack is mounted into the Docker container), leave blank to disable persistence (default).

  • PORT_WEB_UI: Port for the Web user interface / dashboard (default: 8080).

  • <SERVICE>_BACKEND: Custom endpoint URL to use for a specific service, where <SERVICE> is the uppercase service name (currently works for: APIGATEWAY, CLOUDFORMATION, DYNAMODB, ELASTICSEARCH, KINESIS, S3, SNS, SQS). This allows to easily integrate third-party services into LocalStack.

  • FORCE_NONINTERACTIVE: when running with Docker, disables the --interactive and --tty flags. Useful when running headless.

  • DOCKER_FLAGS: Allows to pass custom flags (e.g., volume mounts) to "docker run" when running LocalStack in Docker.

  • DOCKER_CMD: Shell command used to run Docker containers, e.g., set to "sudo docker" to run as sudo (default: docker).

  • SKIP_INFRA_DOWNLOADS: Whether to skip downloading additional infrastructure components (e.g., specific Elasticsearch versions).

  • START_WEB: Flag to control whether the Web API should be started in Docker (values: 0/1; default: 1).

  • LAMBDA_FALLBACK_URL: Fallback URL to use when a non-existing Lambda is invoked. Either records invocations in DynamoDB (value dynamodb://<table_name>) or forwards invocations as a POST request (value http(s)://...).

  • EXTRA_CORS_ALLOWED_HEADERS: Comma-separated list of header names to be be added to Access-Control-Allow-Headers CORS header

  • EXTRA_CORS_EXPOSE_HEADERS: Comma-separated list of header names to be be added to Access-Control-Expose-Headers CORS header

  • LAMBDA_JAVA_OPTS: Allow passing custom JVM options (e.g., -Xmx512M) to Java Lambdas executed in Docker. Use _debug_port_ placeholder to configure the debug port (e.g., -agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=_debug_port_).

Additionally, the following read-only environment variables are available:

  • LOCALSTACK_HOSTNAME: Name of the host where LocalStack services are available. This is needed in order to access the services from within your Lambda functions (e.g., to store an item to DynamoDB or S3 from Lambda). The variable LOCALSTACK_HOSTNAME is available for both, local Lambda execution (LAMBDA_EXECUTOR=local) and execution inside separate Docker containers (LAMBDA_EXECUTOR=docker).

Dynamically updating configuration at runtime

Each of the service APIs listed above defines a backdoor API under the path /?_config_ which allows to dynamically update configuration variables defined in config.py.

For example, to dynamically set KINESIS_ERROR_PROBABILITY=1 at runtime, use the following command:

curl -v -d '{"variable":"KINESIS_ERROR_PROBABILITY","value":1}' 'http://localhost:4568/?_config_'

Service health checks

The service /health check endpoint on the edge port (http://localhost:4566/health by default) provides basic information about the status of each service (e.g., {"s3":"running","es":"starting"}). By default, the endpoint returns cached values that are determined during startup - the status values can be refreshed by adding the reload query parameter: http://localhost:4566/health?reload.

Initializing a fresh instance

When a container is started for the first time, it will execute files with extensions .sh that are found in /docker-entrypoint-initaws.d. Files will be executed in alphabetical order. You can easily create aws resources on localstack using awslocal (or aws) cli tool in the initialization scripts.

Using custom SSL certificates

To use your own SSL certificate (for USE_SSL=1) instead of the randomly generated certificate, you can place a file server.test.pem into the LocalStack temporary directory ($TMPDIR/localstack, or /tmp/localstack by default). The file server.test.pem must contain the key file, as well as the certificate file content:

-----BEGIN PRIVATE KEY-----
...
-----END PRIVATE KEY-----
-----BEGIN CERTIFICATE-----
...
-----END CERTIFICATE-----

Using USE_SSL and own persistent certificate with docker-compose

Typically with docker-compose you can add into docker-compose.yml this volume to the localstack services :

volumes:
      - "${PWD}/ls_tmp:/tmp/localstack"
      - "/var/run/docker.sock:/var/run/docker.sock"

local directory ls_tmp must contains the three files (server.test.pem, server.test.pem.crt, server.test.pem.key)

Accessing the infrastructure via CLI or code

You can point your aws CLI to use the local infrastructure, for example:

aws --endpoint-url=http://localhost:4568 kinesis list-streams
{
    "StreamNames": []
}

Use the below command to install aws CLI, if not installed already.

pip install awscli

Setting up local region and credentials to run localstack

aws requires the region and the credentials to be set in order to run the aws commands. Create the default configuration & the credentials. Below key will ask for the Access key id, secret Access Key, region & output format.

aws configure --profile default

# Config & credential file will be created under ~/.aws folder

NEW: Check out awslocal, a thin CLI wrapper that runs commands directly against LocalStack (no need to specify --endpoint-url anymore). Install it via pip install awscli-local, and then use it as follows:

awslocal kinesis list-streams
{
    "StreamNames": []
}

UPDATE: Use the environment variable $LOCALSTACK_HOSTNAME to determine the target host inside your Lambda function. See Configurations section for more details.

Client Libraries

Integration with nosetests

If you want to use LocalStack in your integration tests (e.g., nosetests), simply fire up the infrastructure in your test setup method and then clean up everything in your teardown method:

from localstack.services import infra

def setup():
    infra.start_infra(asynchronous=True)

def teardown():
    infra.stop_infra()

def my_app_test():
    # here goes your test logic

See the example test file tests/integration/test_integration.py for more details.

Integration with Serverless

You can use the serverless-localstack plugin to easily run Serverless applications on LocalStack. For more information, please check out the plugin repository here: https://github.com/localstack/serverless-localstack

Integration with Terraform

You can use Terraform to provision your resources locally. Please refer to the Terraform AWS Provider docs here on how to configure the API endpoints on localhost.

Using local code with Lambda

In order to mount a local folder, ensure that LAMBDA_REMOTE_DOCKER is set to false then set the S3 bucket name to __local__ and the S3 key to your local path:

awslocal lambda create-function --function-name myLambda \
    --code S3Bucket="__local__",S3Key="/my/local/lambda/folder" \
    --handler index.myHandler \
    --runtime nodejs8.10 \
    --role whatever

Integration with Java/JUnit

In order to use LocalStack with Java, the project ships with a simple JUnit runner, see sample below.

...
import cloud.localstack.LocalstackTestRunner;
import cloud.localstack.TestUtils;
import cloud.localstack.docker.annotation.LocalstackDockerProperties;

@RunWith(LocalstackTestRunner.class)
@LocalstackDockerProperties(services = { "s3", "sqs", "kinesis:77077" })
public class MyCloudAppTest {

  @Test
  public void testLocalS3API() {
    AmazonS3 s3 = TestUtils.getClientS3()
    List<Bucket> buckets = s3.listBuckets();
    ...
  }
}

For more details and a complete list of configuration parameters, please refer to the LocalStack Java Utils repository.

Troubleshooting

  • If you're using AWS Java libraries with Kinesis, please, refer to CBOR protocol issues with the Java SDK guide how to disable CBOR protocol which is not supported by kinesalite.

  • Accessing local S3: To avoid domain name resolution issues, you need to enable path style access on your S3 SDK client. Most AWS SDKs provide a config to achieve that, e.g., for Java:

s3.setS3ClientOptions(S3ClientOptions.builder().setPathStyleAccess(true).build());
// There is also an option to do this if you're using any of the client builder classes:
AmazonS3ClientBuilder builder = AmazonS3ClientBuilder.standard();
builder.withPathStyleAccessEnabled(true);
...

  • Mounting the temp. directory: Note that on MacOS you may have to run TMPDIR=/private$TMPDIR docker-compose up if $TMPDIR contains a symbolic link that cannot be mounted by Docker. (See details here: https://bitbucket.org/atlassian/localstack/issues/40/getting-mounts-failed-on-docker-compose-up)

  • If you run into file permission issues on pip install under Mac OS (e.g., Permission denied: '/Library/Python/2.7/site-packages/six.py'), then you may have to re-install pip via Homebrew (see this discussion thread). Alternatively, try installing with the --user flag: pip install --user localstack

  • If you are deploying within OpenShift, please be aware: the pod must run as root, and the user must have capabilities added to the running pod, in order to allow Elasticsearch to be run as the non-root localstack user.

  • If you are experiencing slow performance with Lambdas in Mac OS, you could either (1) try mounting local code directly into the Lambda container, or (2) disable mounting the temporary directory into the LocalStack container in docker-compose. (See also localstack#2515)

  • The environment variable no_proxy is rewritten by LocalStack. (Internal requests will go straight via localhost, bypassing any proxy configuration).

  • For troubleshooting LocalStack start issues, you can check debug logs by running DEBUG=1 localstack start

  • In case you get errors related to node/nodejs, you may find (this issue comment: localstack#227 (comment)) helpful.

  • If you are using AWS Java libraries and need to disable SSL certificate checking, add -Dcom.amazonaws.sdk.disableCertChecking to the java invocation.

Developing

Requirements for developing or starting locally

To develop new features, or to start the stack locally (outside of Docker), the following additional tools are required:

  • make
  • npm (node.js package manager)
  • java/javac (Java 8 runtime environment and compiler)
  • mvn (Maven, the build system for Java)
  • moto(for testing)
  • docker-compose (for running the localstack using docker-compose)
  • mock (for unit testing)
  • pytest (for unit testing)
  • pytest-cov (to check the unit-testing coverage)

Development Environment

If you pull the repo in order to extend/modify LocalStack, run this command to install all the dependencies:

make install

This will install the required pip dependencies in a local Python virtualenv directory .venv (your global python packages will remain untouched), as well as some node modules in ./localstack/node_modules/. Depending on your system, some pip/npm modules may require additional native libs installed.

The Makefile contains a target to conveniently run the local infrastructure for development:

make infra

Check out the developer guide which contains a few instructions on how to get started with developing (and debugging) features for LocalStack.

Testing

The project contains a set of unit and integration tests that can be kicked off via a make target:

make test

To check the Code Coverage

Once the new feature / bug fix is done, run the unit testing and check for the coverage.

# To run the particular test file (sample)
pytest --cov=localstack tests/unit/test_common.py

# To check the coverage in the console
coverage report

# To check the coverage as html (output will be redirected to the html folder)
coverage html

Web Dashboard

The projects also comes with a simple Web dashboard that allows to view the deployed AWS components and the relationship between them.

localstack web

Other UI Clients

Change Log

Please refer to CHANGELOG.md to see the complete list of changes for each release.

Contributing

We welcome feedback, bug reports, and pull requests!

For pull requests, please stick to the following guidelines:

  • Add tests for any new features and bug fixes. Ideally, each PR should increase the test coverage.
  • Follow the existing code style (e.g., indents). A PEP8 code linting target is included in the Makefile.
  • Put a reasonable amount of comments into the code.
  • Fork localstack on your github user account, do your changes there and then create a PR against main localstack repository.
  • Separate unrelated changes into multiple pull requests.
  • 1 commit per PR: Please squash/rebase multiple commits into one single commit (to keep the history clean).

Please note that by contributing any code or documentation to this repository (by raising pull requests, or otherwise) you explicitly agree to the Contributor License Agreement.

Contributors

This project exists thanks to all the people who contribute.

Backers

Thank you to all our backers! 🙏 [Become a backer]

Sponsors

Support this project by becoming a sponsor. Your logo will show up here with a link to your website. [Become a sponsor]

Stargazers over time

Stargazers over time

License

Copyright (c) 2017-2020 LocalStack maintainers and contributors.

Copyright (c) 2016 Atlassian and others.

This version of LocalStack is released under the Apache License, Version 2.0 (see LICENSE.txt). By downloading and using this software you agree to the End-User License Agreement (EULA).

We build on a number of third-party software tools, including the following:

Third-Party software License
Python/pip modules:
airspeed BSD License
amazon_kclpy Amazon Software License
boto3 Apache License 2.0
coverage Apache License 2.0
docopt MIT License
elasticsearch Apache License 2.0
flask BSD License
flask_swagger MIT License
jsonpath-rw Apache License 2.0
moto Apache License 2.0
requests Apache License 2.0
subprocess32 PSF License
Node.js/npm modules:
kinesalite MIT License
Other tools:
Elasticsearch Apache License 2.0
local-kms MIT License