Creating Lambdas to inspect their execution environment

Creation of three Lambdas sharing the same code

The code generated by this example is available here.

Lets create a new Myrmex project.

myrmex new lambda-profiling @myrmex/iam @myrmex/lambda
cd lambda-profiling

We create a simple execution role for our Lambdas.

myrmex create-role LambdaInspection --model LambdaBasicExecutionRole

We create a node module called inspection. It will inspect its own execution environment.

myrmex create-node-module inspection

The inspection module is created in lambda-profiling/lambda/modules/inspection and only contain a package.json file for now.

Lets create an index.js file that exposes data from the os native module and the process global object in our module.

// lambda-profiling/lambda/modules/inspection/index.js
'use strict';

const os = require('os');

module.exports = () => {
  return {
    host: {
      name: os.hostname(),
      architecture: process.arch,
      memory: os.totalmem(),
      cpus: os.cpus()
    },
    os: {
      platform: process.platform,
      release: os.release(),
      uptime: os.uptime()
    },
    user: {
      uid: process.getuid(),
      gid: process.getgid(),
      groups: process.getgroups
    },
    process: {
      command: process.argv,
      execArgs: process.execArgv,
      pid: process.pid,
      uptime: process.uptime(),
      memoryUsage: process.memoryUsage()
    },
    exec: {
      env: process.env,
      currentDirectory: process.cwd(),
      // mainModule: process.mainModule,
      config: process.config
    }
  };
};

Now we create three Lambdas that will use the inspection module as a dependency. Their are configured with different memory values: 128MB, 512MB and 1536MB.

myrmex create-lambda config-128 --runtime nodejs6.10 --timeout 30 --memory 128 --dependencies inspection --role LambdaInspection
myrmex create-lambda config-512 --runtime nodejs6.10 --timeout 30 --memory 512 --dependencies inspection --role LambdaInspection
myrmex create-lambda config-1536 --runtime nodejs6.10 --timeout 30 --memory 1536 --dependencies inspection --role LambdaInspection

We alter the handler of the three Lambdas to call the inspection module, log its output (it will be visible in cloudwatch) and return it.

// lambda-profiling/lambda/lambdas/config-128/index.js
// lambda-profiling/lambda/lambdas/config-512/index.js
// lambda-profiling/lambda/lambdas/config-1536/index.js
'use strict';

const inspection = require('inspection');

module.exports.handler = function(event, context, cb) {
  const inspect = inspection();
  console.log(JSON.stringify(inspect));
  cb(null, inspect);
};

We can execute the lambdas locally to test them.

# Install dependencies of the Lambdas
myrmex install-lambdas-locally config-128 config-512 config-1536
# Execute Lambdas locally
myrmex test-lambda-locally config-128
myrmex test-lambda-locally config-512
myrmex test-lambda-locally config-1536

Testing the Lambdas in AWS

Lets deploy in AWS!

myrmex deploy-lambdas config-128 config-1536 config-512 --region us-east-1 --environment DEV --alias v0

Now we can execute the Lambdas in AWS using Myrmex, but you can also use the AWS console if you prefer.

myrmex test-lambda config-128 --region us-east-1 --environment DEV --alias v0
myrmex test-lambda config-512 --region us-east-1 --environment DEV --alias v0
myrmex test-lambda config-1536 --region us-east-1 --environment DEV --alias v0

Check the result of the functions to have insights about the execution environment of Lambdas. Observe the variations when calling several times the same function.

TODO: explain results and add a module to profile the use of require() with/without warm up of a Lambda.