simple-lambda-client

A simple, convenient way to invoke aws lambda functions with best practices.

Best practices:

optional logDebug of input and output
throw an error if response contains an error object

Install

npm install --save simple-lambda-client

Example

import { invokeLambdaFunction } from 'simple-lambda-client';
 
const service = 'svc-jobs;
const stage = getStage();
 
export const getJobByUuid = (event: { uuid: string }): Promise<{ job: Job | null }> =>
  invokeLambdaFunction({ service, stage, function: 'getJobByUuid', event });
 
export const getJobsByPostal = (event: { postal: string }): Promise<{ jobs: Job[] }> =>
  invokeLambdaFunction({ service, stage, function: 'getJobsByPostal', event });
 
// ...

Usage

invoke

simple-lambda-client exports a function that lets you invoke lambda functions with best practices.

You can use this function directly if you want...

import { invokeLambdaFunction } from 'simple-lambda-client';
 
const result = await invokeLambdaFunction({ service, stage, function, event });
// ...do amazing things with result...

type

But you'll probably want to add some typedefs and name it for readability:

export const getJobByUuid = (event: { uuid: string }) =>
  invokeLambdaFunction<{ job: Job | null }>({ service, stage, function: 'getJobByUuid', event });

which makes using that a lot easier:

const { job } = await getJobByUuid({ uuid: '__uuid__' });
// ...do amazing things with job

now you can just create a file of those typed lambda function methods, like above, and export each one, and let that be your client.

namespace (if you like)

optionally, you can build a full namespaced client:

// export the namespaced client
export const jobsServiceClient = {
  getJobByUuid,
  // other methods...
};

and add extra context about "where" getJobByUuid is coming from

import { jobsServiceClient } from '../path/to/client';
 
const { job } = await jobsServiceClient.getJobByUuid({ uuid: '__uuid__' });
// ...do amazing things with job

Tips

lambda permissions

if you're using this client from inside a lambda, ensure that this lambda has permission to invoke other lambdas

# serverless.yml
iamRoleStatements:
  - Effect: Allow
    Action:
      - lambda:InvokeFunction
      - lambda:InvokeAsync
    Resource: '*' # TODO: constrain to a specific account, region, service, and stage

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