Serverless Commons Example

build-serverless-template.js

#!/usr/bin/env node
/* eslint-disable no-console */
const path = require('path');
const fs = require('fs');

const templateFile = path.join(__dirname, '../../serverless.templates.yml');
const projectFile = path.join(__dirname, '../../serverless.project.yml');
const profileFile = path.join(__dirname, `../../serverless.project.${process.env.AWS_PROFILE}.yml`);
const slsFile = path.join(__dirname, '../../serverless.yml');

if (!fs.existsSync(projectFile)) {
  console.error('No serverless configuration found.');
  process.exit(0);
}
if (!fs.existsSync(templateFile)) {
  console.error('No serverless templates found.');
  process.exit(0);
}

const banner = '# this file is auto-generated, and will be replaced on npm run configure';
const templates = fs.readFileSync(templateFile);
const project = fs.readFileSync(projectFile);
let sls = `${banner}\n\n${templates}\n# project specific configuration: \n\n${project}`;

if (fs.existsSync(profileFile)) {
  const profile = fs.readFileSync(profileFile);
  sls = `${sls}\n# profile specific configuration: \n\n${profile}`;
}

fs.writeFileSync(slsFile, sls);
console.log('Compiled serverless.yml.');

package.json

{
  "name": "our-commons",
  "version": "2.0.0",
  "description": "Install common configuration for common files of serverless projects.",
  "scripts": {
    "postinstall": "node postinstall.js"
  },
  "bin": {
    "build-dp-sls-template": "./build-dp-sls-template.js"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    // common deps!
  }
}

postinstall.js

/* eslint-disable no-console */
const fs = require('fs');
const path = require('path');
const tasks = require('./scripts.js'); // <- outputs a { scripts: { } } object that defines package.json scripts.

const moduleDir = path.resolve();
const projectDir = path.resolve(moduleDir, '../../');

const postInstall = () => {
  console.info('Updating commons...');

  console.log('Loading config...');
  let config = {
    files: true,
    exclude: [],
    scripts: true,
    build: true,
  };
  const configFile = path.join(projectDir, 'commons.json'); 
  if (fs.existsSync(configFile)) {
    const fragment = JSON.parse(fs.readFileSync(configFile));
    config = Object.assign({}, config, fragment);
  }
  console.log(`Using config: ${JSON.stringify(config)}`);
  const {
    files, exclude, scripts, build,
  } = config;
  // files begining with a '.' are ignored by npm, so need to be saved with the prefix "dot" and are then renamed by script on copy to '.'
  // e.g. dotgitignore becomes .gitignore
  const dotFiles = ['.gitignore', '.npmrc'];
  // all files to keep in sync with common, this is relative to the commons package root:
  const allFiles = ['.editorconfig', '.eslintrc.yml', '.gitignore', '.npmrc', 'serverless.templates.yml',
    'webpack.config.js', 'webpack.base.config.js', 'webpack.prod.config.js', 'webpack.test.config.js'];
  const copy = allFiles
    .filter(f => exclude.indexOf(f) < 0)
    .map(f => (dotFiles.indexOf(f) > -1 ? f.replace(/^\./, 'dot') : f));

  if (files) {
    copy.forEach((f) => {
      console.info(`Installing common ${f.replace(/^dot/, '.')}...`);
      fs
        .createReadStream(path.join(moduleDir, f))
        .pipe(fs.createWriteStream(path.join(projectDir, f.replace(/^dot/, '.'))));
    });
  }

  if (scripts) {
    console.info('Installing common scripts...');
    const packageJson = path.join(projectDir, 'package.json');
    fs.readFile(packageJson, (err, data) => {
      const original = JSON.parse(data);
      const updated = Object.assign({}, original, tasks);
      fs.writeFile(packageJson, JSON.stringify(updated, null, 2));
    });
  }

  if (!build) {
    console.info('Deleting build...');
    fs.unlinkSync(path.join(projectDir, '.gitlab-ci.yml'));
  }
};

if (process.env.DP_SLS_SKIP_INSTALL) {
  console.log('Skipping sls-common post install.');
} else {
  postInstall();
}
/* eslint-enable no-console */

serverless.templates.yml

# for example

plugins:
  # it doesn't normally hurt to load a plugin you won't use, so make this all common
  - serverless-webpack
  - serverless-aws-documentation
  - serverless-plugin-bind-deployment-id
  - serverless-plugin-tracing

# common options
package:
  individually: true

# templates

.node-provider: &provider # you can now use this as '<<: *provider' to mix-in common options
  name: aws
  runtime: nodejs8.10
  stage: local
  region: eu-west-1