feat(LocalLambdaService): Invoke Local Lambdas through a Local Lambda Service #508

jfuss · 2018-06-26T19:54:25Z

Details:

Stand up a localhost endpoint
Listen to path /2015-03-31/functions/<function_name>/invocations for a POST
Invoke the Local Lambda function based on the request.

Description of changes:
This was modeled off of the API GW local service.
Adds a class that is responsible for standing up a Local Lambda Service. Functional and unit test pass but the code is not used in any context outside of this. Currently, only the happy path is implemented.

I used the AWS CLI and pointed it to this localhost service to inspect the path and request. I have not done a deeper dive into the Lambda Service, so things may be different than the cloud service at the moment.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

jfuss · 2018-06-26T20:50:23Z

samcli/local/lambda_service/service.py

+
+        Parameters
+        ----------
+        function_name_list list of str


I had two options here:

Use a list of Function Logical Ids

A list of Function NamedTuple

I went with the first to not couple them together but I think it might be ok. Wanted to get your thoughts on this @sanathkr

This looks good. The NamedTuple has too much information which is not a concern of this class

Ya that is why I originally leaned this way but couldn't completely convince myself it was right. :)

jfuss · 2018-06-26T20:54:51Z

samcli/local/lambda_service/service.py

+        self._app = Flask(__name__)
+
+        for function_name in self.function_name_list:
+            path = '/2015-03-31/functions/{}/invocations'.format(function_name)


At the moment, I create a path for each function but not sure this is the right approach at the moment. There is a date (api version) in the path of the API and am not sure if we should be hardcoding that into the path for Flask. Instead, we can catch all paths and do some path matching (we have to do some of this already to get the Function Logical Id out of the path). If we do the path matching, we can ignore the first part (2015-03-31). This would make our code a little more future proof but we have do handle most of the error cases and route handling ourselves (and not get some of this from Flask).

I am leaning towards accepting all paths and doing the path matching/inspection but haven't fully convinced myself yet. Thoughts?

Invoke might be version locked today, but could change in the future. Since we only support one Invoke API, this is good for now. It doesn't lead us thru one way doors and can be changed easily in the future.

jfuss · 2018-06-26T20:56:38Z

@sanathkr I made two comments and things I would like your thoughts on :)

sanathkr

Great start! I am excited about this 🎉

sanathkr · 2018-06-28T19:01:25Z

samcli/local/lambda_service/service.py

+LOG = logging.getLogger(__name__)
+
+
+class LocalLambdaService(BaseService):


worth calling this something other than LocalLambdaService. "Service" isn't too clear on what it means

sanathkr · 2018-06-28T19:02:46Z

samcli/local/lambda_service/service.py

+
+class LocalLambdaService(BaseService):
+
+    _DEFAULT_PORT = 3001


I don't like hard-coding defaults like port & host deep within this class. Let's make the port mandatory & have it dependency injected by the caller. The caller could read from a config file or from CLI args.

We did this for the APIGW service but I don't think it is a good idea there either

Make sense. I can't recall why I did this initially for APIGW originally. Will work on cleaning this up (and for APIGW as well).

sanathkr · 2018-06-28T19:04:24Z

samcli/local/lambda_service/service.py

+
+        Parameters
+        ----------
+        function_name_list list of str


This looks good. The NamedTuple has too much information which is not a concern of this class

sanathkr · 2018-06-28T19:08:14Z

samcli/local/lambda_service/service.py

+        self._app = Flask(__name__)
+
+        for function_name in self.function_name_list:
+            path = '/2015-03-31/functions/{}/invocations'.format(function_name)


Invoke might be version locked today, but could change in the future. Since we only support one Invoke API, this is good for now. It doesn't lead us thru one way doors and can be changed easily in the future.

sanathkr · 2018-06-28T19:09:25Z

samcli/local/lambda_service/service.py

+        if not self._app:
+            raise RuntimeError("The application must be created before running")
+
+        # Flask can operate as a single threaded server (which is default) and a multi-threaded server which is


so this logic is spread in two classes now? This one and the APIGW Service?

Ya. I didn't get far enough to get this abstracted yet but it totally should be. Will work on getting that and cleaning up the current 'Base' class.

sanathkr · 2018-06-28T19:10:24Z

samcli/local/lambda_service/service.py

+        """
+        flask_request = request
+
+        function_name_regex = re.compile(r'/2015-03-31/functions/(.*)/invocations')


you don't need a regex here. Flask should have already parsed the {} part out from the path.

I constructed every endpoint but instead, I can move to letting flask do this. It will clean up a lot of this code, which is great. Will update.

sanathkr · 2018-06-28T19:11:53Z

samcli/local/lambda_service/service.py

+        stdout_stream = io.BytesIO()
+
+        try:
+            self.lambda_runner.invoke(function_name, {}, stdout=stdout_stream, stderr=self.stderr)


why is the event parameter empty dict? We should be passing the request's body to event

Because I didn't get that far just yet :). I focused on just getting the main details working. It will be apart of the next commit.

sanathkr · 2018-06-28T19:13:21Z

tests/functional/local/lambda_service/test_lambda_service.py

+        self.assertEquals(response.status_code, 200)
+
+
+def make_service(list_of_function_names, function_provider, cwd):


Move all the make_service and random_port to a util class. Too many places where this is repated

I choose to ignore this but realize we need to deal with this sooner rather than later. I will try to setup a 'framework' functional tests can follow like the one we have for integ. Updating the existing functional tests will come later though. I want to keep this PR scoped (I already feel it is getting a little large).

sanathkr · 2018-06-28T19:14:19Z

samcli/local/lambda_service/service.py

@@ -0,0 +1,128 @@
+"""Local Lambda Service"""
+


Can we rename the file to something else? The word "service" is very generic, even though I know the file is creating a service

sanathkr · 2018-06-28T23:30:29Z

samcli/local/lambda_service/service.py

+        self._app = Flask(__name__)
+
+        for function_name in self.function_name_list:
+            path = '/2015-03-31/functions/{}/invocations'.format(function_name)


Also, I think the path must respond to /lambda/2015.... because, then users can set the general AWS endpoint to be localhost:3001 instead of overriding just the Lambda one. What do you think?

sanathkr · 2018-06-28T23:36:31Z

Documenting here for reference but not part of this PR: This command should automatically create and use a default Docker network called samcliproxy.example.com. All the Docker containers running the Lambda function will run inside this network. This will allow customers to do something like:

var lambda = new AWS.Lambda()
if(process.env.AWS_SAM_LOCAL) {
  // only run inside local lambda runner
  // Note the endpoint name
   var ep = new AWS.Endpoint('samcliproxy.example.com:3001');
   var lambda = new AWS.Lambda({endpoint: ep})
}

This will allow one local Lambda to call another locally.

jfuss · 2018-06-29T18:42:50Z

@sanathkr Updated base on your comments. I still think this is WIP. I still need up to update some naming (more on files/paths) and I combines to classes into one for because it was easy but they do not belong together (in the localhost runner file). It felt wrong to create yet another file for some 'helper related methods'. But would still like your thoughts on what is here.

sanathkr

This looks much better! I have a few minor suggestions to cleanup the base class, nothing too critical.

sanathkr · 2018-07-02T13:15:56Z

samcli/local/services/localhost_runner.py

+
+    def __init__(self, lambda_runner, port, host, stderr=None):
+        """
+        Creates a BaseService class


update class name

Missed that one.

sanathkr · 2018-07-02T13:17:06Z

samcli/local/services/localhost_runner.py

+        return response
+
+
+class LambdaOutputParser(object):


optional: doesn't need a class. It could be just its own top-level method

I am going to leave this as a class for now. We need to read the output for the Lambda to see if the return value from the container is a user exception/error. This is so we can properly handle some error cases and setting headers correctly. I was planning to use this class to contain that as well. I may just move it then but want to see how the structure/code looks after I handle that.

sanathkr · 2018-07-02T13:18:28Z

samcli/local/services/localhost_runner.py

+            Optional. port for the service to start listening on Defaults to 3000
+        host str
+            Optional. host to start the service on Defaults to '127.0.0.1
+        stderr io.BaseIO


stderr is not used in this class

I originally placed this here because it was used in both Local APIGW and Local Lambda. Since it is unused here, I pushed this up the hierarchy.

sanathkr · 2018-07-02T13:20:02Z

samcli/local/services/localhost_runner.py

+
+        Parameters
+        ----------
+        lambda_runner samcli.commands.local.lib.local_lambda.LocalLambdaRunner


this is used only to set is_debugging flag. Instead, can't you just take a is_debugging flag in the constructor and remove lambda_runner from it? That way this class is only about encapsulating Flask. So any regular class can inherit from this one to immediately become a "service".

In this light, BaseService makes sense for class name, or BaseLocalService. Subclasses could be LocalApigwService and LocalLambdaService. I won't nit pick on the names, but this is my two cents to keep them consistent.

Good call out. Will update the lambda_runner to is_debugging.

NAMING IS HARD!!! :) I like your suggestion more. Will update.

sanathkr · 2018-07-02T13:25:56Z

samcli/local/lambda_service/local_invoke.py

+            # TODO Change this
+            raise Exception('Change this later')
+
+        lambda_response, lambda_logs = LambdaOutputParser.get_lambda_output(stdout_stream)


Thanks for the refactor, this method reads fluently :)

sanathkr

Looks great! I like the new class name. Suits well :) Do you want me to approve & merge this PR while you build on top of this?

jfuss · 2018-07-03T13:03:33Z

@sanathkr

Do you want me to approve & merge this PR while you build on top of this?

Let's get this merged if you feel it is ready. I have spun off a branch locally that has the error handling cases (based on this already). I prefer incremental and scoped changes :)

I forgot to update the title and issue above. Let me do that now.

…quest Details: * Moved shared code between APIGW and Lambda service to a Base Class * Updated the Invoke function on the LocalLambdaService to invoke the Local Lambda based on the request * Updated Functional tests for invoking the Local Lambda

Details: * Updated some names * Forwarded request body to the event of the invoke * Added functional tests for echoing the event sent to lambda * More refactoring around shared code

jfuss · 2018-07-03T14:31:41Z

@sanathkr I force updated with the changes for HEAD of develop

sanathkr

LGTM

rohandesai · 2018-08-30T22:41:54Z

@sanathkr Is this supported in 0.4.0? I am trying to trigger a lambda locally using another lambda which is triggered by API GW. Do I need to add an Event type to the cloudformation template? Also, I tried the code posted above by you, but i can't seem to trigger the other lambda locally.

Edit1: I upgraded to 0.6.0 and I can start the lambda service locally. However, I still can't trigger the lamdba locally. Do I need to specify anything for events in the CloudFormation template?

Edit2: I got this working. I was running into a ECONNREFUSED error for 127.0.0.1. I have worked around it by aliasing the loopback address. Please let me know if there is a better approach to this.

markwilson · 2019-01-01T13:20:43Z

@rohandesai, can you confirm how you got this working?

I'm trying to do: API Gateway ➡️ Function1 ➡️ Function2. But I get a connection refused issue when trying to invoke Function2: dial tcp 127.0.0.1:3000: connect: connection refused.

main.go:-

package main

import (
	"github.com/aws/aws-lambda-go/lambda"
	"github.com/aws/aws-lambda-go/events"
	"github.com/aws/aws-sdk-go/aws/session"
	"github.com/aws/aws-sdk-go/aws"
	lambdasvc "github.com/aws/aws-sdk-go/service/lambda"
	"os"
)

var svc *lambdasvc.Lambda

func init() {
	if os.Getenv("AWS_SAM_LOCAL") == "true" {
		const e = "127.0.0.1:3000"
		svc = lambdasvc.New(session.Must(session.NewSession()), aws.NewConfig().WithEndpoint(e))
	} else {
		svc = lambdasvc.New(session.Must(session.NewSession()))
	}
}

func main() {
	lambda.Start(func (_ events.APIGatewayProxyRequest) (events.APIGatewayProxyResponse, error) {
		input := &lambdasvc.InvokeInput{
			ClientContext:  aws.String("Test"),
			FunctionName:   aws.String("Function2"),
			InvocationType: aws.String("Event"),
		}

		r, err := svc.Invoke(input)
		if err != nil {
			return events.APIGatewayProxyResponse{}, err
		}

		return events.APIGatewayProxyResponse{
			Body: r.GoString(),
		}, nil
	})
}

template.yaml:-

AWSTemplateFormatVersion : '2010-09-09'
Transform: AWS::Serverless-2016-10-31

Resources:
  Function1:
    Type: AWS::Serverless::Function
    Properties:
      Runtime: go1.x
      Handler: function1/function1
      Events:
        HttpHandler:
          Type: Api
          Properties:
            Path: '/'
            Method: get
  Function2:
    Type: AWS::Serverless::Function
    Properties:
      Runtime: go1.x
      Handler: function2/function2

rohandesai · 2019-01-02T17:50:44Z

@markwilson Try aliasing the loopback address by using the following command -
sudo ifconfig lo0 alias <ip>. Then run the lambda service locally and try.

markwilson · 2019-01-02T20:48:08Z

I tried running this:-

sudo ifconfig lo0 alias 10.1.1.1

... and updated to use 10.1.1.1:3000 as the Lambda endpoint configuration.

It didn't work though. I'll keep trying...

It would be good to get some official docs on how this is supposed to work 😅

piejanssens · 2019-04-01T15:40:02Z

Is there any official documentation by now?

kylevoyto · 2019-04-02T15:40:46Z

@markwilson I needed to use host.docker.internal:3000 to connect to the endpoint on the host machine since the function code runs inside a container.

https://docs.docker.com/docker-for-mac/networking/#i-want-to-connect-from-a-container-to-a-service-on-the-host

surbhi029 · 2019-10-11T06:46:57Z

I have created two lambdas -validateuserpermission and updateuserpermission. Here is the situation updateuserpermission calls validateuserpermission internally.
Now I did sam local start-lamda and then sam local invoke updateuserpermission which internally call validateuserpermission. I am getting below error

"Could not connect to the endpoint URL: "http://127.0.0.1:3001/2015-03-31/functions/validateuserpermission/invocations\""

ON AWS console this is working but not able to work it from SAM local.

However, if validateuserpermission invocation is removed from updateuserpermission , both lambda works fine in SAM LOCAL.

Could you please help me in resolving this issue so that i would be able to test this situation.

mike-tedford · 2019-10-14T18:01:39Z

+1

Any update on this? We need an officially supported way to locally invoke Lambda A from API Gateway, which in turn invokes Lambda B, built by the SAM CLI

ofhouse · 2020-08-25T18:31:35Z

For anyone wondering how to use it, here is an example:

sam local start-lambda --port 3000 --region local

You can then invoke your lambda through the aws-sdk (Example in JavaScript):

const { Lambda } = require('aws-sdk');

const lambda = new Lambda({
  endpoint: 'http://localhost:3000',
  region: 'local',
});

lambda
  .invoke({
    FunctionName: 'myFunction',
    InvocationType: 'RequestResponse',
    Payload: JSON.stringify({ hello: 'world' }),
  })
  .promise()
  .then((result) => {
    console.log('Received Response:', result.Payload);
  })
  .catch((error) => {
    console.error('Error:', error);
  });

You could also run this code from inside another local Lambda.
For more info about this run sam local start-lambda --help

danjenson · 2020-12-04T10:31:31Z

Is there a python example? I can't seem to find a way to do this from one python function to another locally, and I'm not sure boto is respecting any options I pass it when I get the lambda client, i.e.

lambda_client = boto3.client('lambda',
                             endpoint_url="http://127.0.0.1:3001",
                             use_ssl=False,
                             verify=False)

* Add nodejs20.x support for samcli * Add nodejs20.x as preview runtime * change github action to install nodejs 20.x --------- Co-authored-by: Mohamed Elasmar <[email protected]>

* Add nodejs20.x support for samcli (#508) * Add nodejs20.x support for samcli * Add nodejs20.x as preview runtime * change github action to install nodejs 20.x --------- Co-authored-by: Mohamed Elasmar <[email protected]> * move test to arm64 --------- Co-authored-by: Andrea Culot <[email protected]> Co-authored-by: Mohamed Elasmar <[email protected]> Co-authored-by: Haresh Nasit <[email protected]>

jfuss requested a review from sanathkr June 26, 2018 19:54

jfuss commented Jun 26, 2018

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sanathkr suggested changes Jun 28, 2018

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sanathkr added the stage/in-progress A fix is being worked on label Jun 28, 2018

sanathkr reviewed Jun 28, 2018

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sanathkr mentioned this pull request Jun 28, 2018

Support one Local Lambda calling another Local Lambda scenarios #510

Open

sanathkr suggested changes Jul 2, 2018

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sanathkr reviewed Jul 3, 2018

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jfuss changed the title ~~[WIP] Initial implementation to start up Local Lambda Service~~ feat(LocalLambdaService): Invoke Local Lambdas through a Local Lambda Service Jul 3, 2018

jfuss added 6 commits July 3, 2018 06:56

Initial implementation to start up Local Lambda Service

d2afc9b

fix naming of Functional tests

a689482

Update unit tests based on refactor of Lambda and APIGW Service

29e117c

Updated based on feedback from PR

d8e5c68

Details: * Updated some names * Forwarded request body to the event of the invoke * Added functional tests for echoing the event sent to lambda * More refactoring around shared code

More naming updates based on feedback

628a506

jfuss force-pushed the local-lambda-service branch from 87cd117 to 628a506 Compare July 3, 2018 14:28

sanathkr approved these changes Jul 4, 2018

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sanathkr merged commit bd09c29 into aws:develop Jul 4, 2018

jfuss mentioned this pull request Jul 6, 2018

[Feature request] offline mode / local cache #529

Closed

jfuss mentioned this pull request Oct 18, 2018

Container cannot be connected to host network #669

Closed

ejhayes mentioned this pull request Nov 5, 2018

feat(event-invocation-type): Add support for Event invocation type #749

Closed

		LOG = logging.getLogger(__name__)


		class LocalLambdaService(BaseService):

		self.assertEquals(response.status_code, 200)


		def make_service(list_of_function_names, function_provider, cwd):

feat(LocalLambdaService): Invoke Local Lambdas through a Local Lambda Service #508

feat(LocalLambdaService): Invoke Local Lambdas through a Local Lambda Service #508

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