s3-resizer: An HCL repository from MeLlamoPablo

What is it?

It's AWS Lambda, which is a compute service that lets you run code without provisioning or managing servers.

Read more about AWS Lambda.

Demo

https://sagidm.github.io/smartuploader/examples/4.s3-resizer.html

What this lambda provides

Let's say we have some shared image in S3, for example:
https://example.com/images/pretty_photo.jpg

to resize on fly this image to, say, 150x150, we can make a request like this:
https://example.com/images/150x150/pretty_photo.jpg

So, if there's not image in this path, it's redirected to lambda and, after a moment, lambda creates the suitable image and then redirects back. We'll obviously have a new image next time.

Instead of WxH there're some extra available magic paths:
.../AUTOx150/...
.../150xAUTO/...
or
.../150x150_max/...
.../150x150_min/...

Note that s3-resizer does not enlarge an image if the original image width or height are less than the requested dimensions. You can read about withoutEnlargement method.

Setting up

s3-resizer can be easily bootstrapped using Terraform. If you would rather do it manually, you can take a look at the old setup instructions.

Prerequisites

The Terraform CLI installed in your system, version v0.12.25 or above.
The latest s3-resizer release for nodejs_12.13.0. You can grab it from here.
An Amazon S3 bucket where the source images will be stored. This bucket does not necessarily have to be public.

Note: the Terraform plan does not create this bucket to facilitate integration with existing infrastructure.
An AWS IAM user with administrator permissions and programmatic access. This user is temporary and should be deleted after the infrastructure creation finishes.
Optionally, if you want to host the service in a custom subdomain, you will need to provision an AWS Certificate Manager certificate for your subdomain. If you don't specify a domain, the default CloudFront endpoint will be used.

Note: the Terraform plan does not create either the certificate, nor the validation DNS entries in your behalf. This is also to facilitate integration with existing infrastructure. For example, you may not want or be able to host your DNS on Amazon Route 53.

Overview

The Terraform plan will create:

The AWS Lambda function containing the s3-resizer code.
An API Gateway API to interface with the function.
An Amazon S3 bucket where the image outputs will be stored.

Note: this is a different bucket than the source bucket that you must create manually.
An Amazon CloudFront distribution that will cache the images from the S3 bucket and distribute them to the internet.
All the necessary policies, roles and permissions to make everything work together.

Bootstrapping instructions

Clone this repository:

git clone https://github.com/sagidM/s3-resizer.git

Navigate to the infra directory:
```
cd s3-resizer/infra
```
Place the s3-resizer code that you downloaded from the releases page inside the infra directory. It must be named exactly s3-resizer_nodejs_12.13.0.zip.
Run:
```
terraform init
```

Add the AWS credentials to the environment:

export AWS_ACCESS_KEY_ID="XXXXXXXXXXXXXXXXXXXX"
export AWS_SECRET_ACCESS_KEY="XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"

Run the Terraform plan:
```
terraform plan -out tfplan \
    -var 'source_bucket=my-source-s3-bucket-name' \
    -var 'service_domain_name=img.example.com' \
    -var 'size_whitelist=AUTOx150 300x200 100x100_max'
```
- In source_bucket, pass the name of the source bucket that you created.
- If you wish to use a custom domain, pass it in service_domain_name. If you want to use the default cloudfront generated domain, remove this line.
- In size_whitelist, define your whitelisted sizes. If you wish to allow any size, remove this line.
Note: you may change these values at any time by running the plan command again and applying the changes.

Review the Terraform plan. You should see something like this:

Plan: 13 to add, 0 to change, 0 to destroy.

------------------------------------------------------------------------

This plan was saved to: tfplan

To perform exactly these actions, run the following command to apply:
    terraform apply "plan"

Apply the Terraform plan:

terraform apply tfplan && rm tfplan

It will take a while. Afterwards, you should see something like this:

Apply complete! Resources: 13 added, 0 changed, 0 destroyed.

Outputs:

cloudfront_endpoint = d37qm260myncmt.cloudfront.net

If you used a custom domain, you will need to set up the ALIAS or CNAME record. If you use Amazon Route 53, this document explains how to do it.

If you use a DNS provider other than Route 53, you will need to set up a CNAME record pointing to the generated CloudFront endpoint:
```
img.example.com. CNAME d37qm260myncmt.cloudfront.net
```
A terraform.tfstate file will be created inside the infra directory. Keep this file somewhere safe, as it will allow to easily make modifications to the created infrastructure. For example, if you want to modify the whitelist, or add a custom domain, you will need this file.

It will also allow you to easily destroy all provisioned resources instead of having to delete them manually. Please keep in mind that in order to destroy the output S3 bucket, you will need to delete all items on it first, else terraform destroy will fail.