AWS 람다, S3를 이용한 이미지 리사이징

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "VisualEditor0",
      "Effect": "Allow",
      "Action": ["logs:CreateLogStream", "logs:CreateLogGroup", "logs:PutLogEvents"],
      "Resource": "arn:aws:logs:*:*:*"
    },
    {
      "Sid": "VisualEditor1",
      "Effect": "Allow",
      "Action": ["s3:PutObject", "s3:GetObject"],
      "Resource": "*"
    }
  ]
}

// dependencies
const AWS = require('aws-sdk');
const util = require('util');
const sharp = require('sharp');

// get reference to S3 client
const s3 = new AWS.S3();

exports.handler = async (event, context, callback) => {
  // Read options from the event parameter.
  console.log('Reading options from event:\n', util.inspect(event, {depth: 5}));

  const srcBucket = event.Records[0].s3.bucket.name;
  // Object key may have spaces or unicode non-ASCII characters.
  const srcKey = decodeURIComponent(event.Records[0].s3.object.key.replace(/\+/g, ' '));
  const dstBucket = srcBucket + '-resized';

  // Infer the image type from the file suffix.
  const typeMatch = srcKey.match(/\.([^.]*)$/);
  if (!typeMatch) {
    console.log('Could not determine the image type.');
    return;
  }

  // Check that the image type is supported
  const imageType = typeMatch[1].toLowerCase();
  if (imageType != 'jpg' && imageType != 'png') {
    console.log(`Unsupported image type: ${imageType}`);
    return;
  }

  // Download the image from the S3 source bucket.

  try {
    const params = {
      Bucket: srcBucket,
      Key: srcKey,
    };
    var origimage = await s3.getObject(params).promise();
  } catch (error) {
    console.log(error);
    return;
  }

  // set thumbnail width. Resize will set the height automatically to maintain aspect ratio.

  /**
   * SMALL (width 368)
   */
  const smallWidth = 368;
  const smallDstKey = 'small-' + srcKey;
  // Use the sharp module to resize the image and save in a buffer.
  try {
    var buffer = await sharp(origimage.Body)
      .resize({
        width: smallWidth,
        withoutEnlargement: true,
      })
      .toBuffer();
  } catch (error) {
    console.log(error);
    return;
  }

  // Upload the thumbnail image to the destination bucket
  try {
    const destparams = {
      Bucket: dstBucket,
      Key: smallDstKey,
      Body: buffer,
      ContentType: 'image',
    };

    const putResult = await s3.putObject(destparams).promise();
  } catch (error) {
    console.log(error);
    return;
  }

  /**
   * MEDIUM (width 720)
   */
  const mediumWidth = 720;
  const mediumDstKey = 'medium-' + srcKey;
  // Use the sharp module to resize the image and save in a buffer.
  try {
    var buffer = await sharp(origimage.Body)
      .resize({
        width: mediumWidth,
        withoutEnlargement: true,
      })
      .toBuffer();
  } catch (error) {
    console.log(error);
    return;
  }

  // Upload the thumbnail image to the destination bucket
  try {
    const destparams = {
      Bucket: dstBucket,
      Key: mediumDstKey,
      Body: buffer,
      ContentType: 'image',
    };

    const putResult = await s3.putObject(destparams).promise();
  } catch (error) {
    console.log(error);
    return;
  }
  /**
   * LARGE (width 1440)
   */
  const largeWidth = 1440;
  const largeDstKey = 'large-' + srcKey;
  // Use the sharp module to resize the image and save in a buffer.
  try {
    var buffer = await sharp(origimage.Body)
      .resize({
        width: largeWidth,
        withoutEnlargement: true,
      })
      .toBuffer();
  } catch (error) {
    console.log(error);
    return;
  }

  // Upload the thumbnail image to the destination bucket
  try {
    const destparams = {
      Bucket: dstBucket,
      Key: largeDstKey,
      Body: buffer,
      ContentType: 'image',
    };

    const putResult = await s3.putObject(destparams).promise();
  } catch (error) {
    console.log(error);
    return;
  }

  console.log('Successfully resized ' + srcBucket + '/' + srcKey + ' and uploaded to ' + dstBucket);
};