audiowaveform for lambda - https://github.com/bbc/audiowaveform

index.js

// install first binaries from http://ffxsam.s3.amazonaws.com/public/audiowaveform-lambda.zip
// @author Andrzej Ojczenasz https://github.com/ojczeo
// @version '1.0.0'
'use strict';

process.env.PATH = process.env.PATH + ':' + process.env.LAMBDA_TASK_ROOT + '/bin';

function getExtension(filename) {
    var ext = path.extname(filename||'').split('.');
    return ext[ext.length - 1];
};

const aws = require('aws-sdk');
const s3 = new aws.S3({apiVersion: '2006-03-01'});
const child_process = require('child_process');
const uuidv4 = require('uuid/v4');
const fs = require('fs');
const path = require('path');
const os = require('os');

exports.handler = (event, context, callback) => {

    // vars
    const { w, h, pps, b, ext, bucket, bg = '555555' } = event;
    const tempDir = process.env['TEMP'] || (0, os.tmpdir)();

    // input
    const key = decodeURIComponent(event.key.replace(/\+/g, ' '));
    const localFileName = (0, path.join)(tempDir, `${uuidv4()}.${getExtension(event.key)}`);
    const localFile = fs.createWriteStream(localFileName);

    // output
    const outputKey = decodeURIComponent(event.outputKey.replace(/\+/g, ' '));
    const resFile = `${uuidv4()}.${ext}`;
    const resPath = (0, path.join)(tempDir, resFile);

    // audiowaveform args
    const args = [
        '-i', localFileName,
        '-w', w,
        '-h', h,
        '-c', 'audition',
        '--no-axis-labels',
        '--pixels-per-second', pps,
        '--background-color', bg,
        '-b', b,
        '-o', resPath
    ];

    const cb = (error, stdout) => {
        if (error) {
            console.log('audiowaveform error: ', error);
            callback(error);
        } else {
            console.log('audiowaveform success ', stdout);
            fs.readFile(resPath, (err, data) => {
                if (err) {
                    console.log('File read error: ', err);
                    callback(err);
                }
                const upload_params = {
                    Bucket: bucket,
                    Key: outputKey,
                    Body: data
                };
                console.log('upload params: ', upload_params);
                s3.putObject(upload_params, err => {
                    if (err) {
                        console.log('Upload error', err);
                        callback(err);
                    }
                    else {
                        console.log('Upload success');
                        callback(null, { key: outputKey });
                    }
                })
            });
        }
    };

    s3.getObject({
        Bucket: bucket,
        Key: key,
    })
    .createReadStream()
        .on('error', (err) => {
            console.log('createReadStream error', err);
            callback(err);
        })
    .pipe(localFile) // write to local /tmp directory
        .on('data', (data) => {
            console.log('data received', data);
        })
        .on('finish', function(endRes) {
            console.log(endRes);
            (0, child_process.execFile)('audiowaveform', args, {}, cb)
                .on('error', (err) => {
                    console.log('audiowaveform error', err);
                    callback(err);
                })
        })
        .on('err', function(err) {
            console.log('download error', err);
            callback(err);
        })
};