Author: Benjamin Coe @benjamincoe
Thumbd is an image thumbnailing server built on top of Node.js, SQS, S3, and ImageMagick.
apt-get install imagemagick
npm install thumbd
Thumbd requires the following environment variables to be set:
- AWS_KEY the key for your AWS account (the IAM user must have access to the appropriate SQS and S3 resources).
- AWS_SECRET the AWS secret key.
- BUCKET the bucket to download the original images from. The thumbnails will also be placed in this bucket.
- SQS_QUEUE the queue URL to listen for image thumbnaling. You can find this URL from your AWS control panel, it begins with
https://
.
You can export these variables to your environment, or specify them when running the thumbd CLI.
Personally, I set these environment variables in a .env file and execute thumbd using Foreman.
The thumbd server:
- listens for thumbnailing jobs on the queue specified.
- downloads the original image from our thumbnailng S3 bucket, or from an HTTP(s) resource.
- HTTP resources are prefixed with http:// or https://.
- S3 resources are a path to the image in the S3 bucket indicated by the BUCKET environment variable.
- Uses ImageMagick to perform a set of transformations on the image.
- uploads the thumbnails created back to S3, with the following naming convention: [original filename excluding extension]_[thumbnail suffix].jpg
Assume that the following thumbnail job was received over SQS:
{
"original": "example.png",
"descriptions": [
{
"suffix": "tiny",
"width": 48,
"height": 48
},
{
"suffix": "small",
"width": 100,
"height": 100,
"background": "red"
},
{
"suffix": "medium",
"width": 150,
"height": 150,
"strategy": "bounded"
}
]
}
Once thumbd processes the job, the files stored in S3 will look something like this:
- /example.png
- /example_tiny.jpg
- /example_small.jpg
- /example_medium.jpg
The descriptions received in the thumbnail job describe the way in which thumbnails should be generated.
description accepts the following keys:
- suffix a suffix describing the thumbnail.
- width the width of the thumbnail.
- height the height of the thumbnail.
- background background color for matte.
- strategy indicate an approach for creating the thumbnail.
- matted maintain aspect ratio, places image on width x height matte.
- bounded (default) maintain aspect ratio, don't place image on matte.
- fill both resizes and zooms into an image, filling the specified dimensions.
Starting the server:
thumbd server --aws_key=<key> --aws_secret=<secret> --tmp_dir=</tmp> --sqs_queue=<sqs queue name> --bucket=<s3 thumbnail bucket>
Manually submitting an SQS thumbnailing job (useful for testing purposes):
thumbd thumbnail --remote_image=<path to image s3 or http> --thumbnail_descriptions=<path to thumbnail description JSON file> --aws_key=<key> --aws_secret=<secret> --sqs_queue=<sqs queue name>
- remote_image indicates the S3 object to perform the thumbnailing operations on.
- thumbnail_descriptions the path to a JSON file describing the dimensions of the thumbnails that should be created (see example.json in the data directory).
thumbd is a rough first pass at creating an efficient, easy to deploy, thumbnailing pipeline. I need thumbd for work, and will be actively contributing to this project.
Copyright (c) 2012 Attachments.me. See LICENSE.txt for further details.