dynamic forms healthcheck npm

Summary

Supports AWS lambdas implemented in NodeJs using express for middleware and routing. Once added as a middleware function, the healthcheck module provides a GET endpoint that responds with a JSON body and appropriate HTTP status codes to indiate if the lambda is healthy or not.

Getting started

Required change to package.json for all health checks

The healthcheck module reads a file version.json at the root of the lambda distribution files. Modify package.json by adding a version command to create this file during the build phase:

#package.json
#Adds a version command that writes out the version from the parent package.json and writes it to a file in the deployment folder
"scripts": {
    ...,
    "build": "mkdir -p dist && <current build> && npm run version",
    "version": "jq '. | {version: .version}' package.json > ./dist/version.json"
}

The healthcheck module requires a file named version.json to exist at the root of the files deployed as the lambda. This file is read and the version is returned in the healthcheck response as the first check. If the version.json does not exist, the heathcheck will return a warn status as the initial status.

Default lambda health check

#Server.js
const HealthCheck = require('healthCheck');
...
app.use('/healthCheck', new HealthCheck().handler())

Custom health check

#Server.js
const { HealthCheck, Check } = require('healthCheck');
...
const options = {
    checks: [new Check("custom-check", "pass")]
};

app.use('/healthCheck', new HealthCheck(options).handler())

Development

Use TDD

Testing

npm run test

Deployment

Set auth token environment variable:

export NPM_TOKEN=<token>

Publish NPM

npm publish