jaysoifer
I need to provide some context before asking the question:
CONTEXT
I have a Phoenix application that is being deployed to Heroku. As default, Brunch is being used to compile the Static Assets like .js,.css and images.
- Those assets are stored on
./assets(Phoenix 1.3). - Those assets are compiled to
./priv/static/.
The compilation process generates a cache_manifest.json, after the assets are digested using MD5 fingerprinting.
It maybe important to notice I’m using CloudFlare’s free version as a CDN.
I’m not concerned about user uploaded assets, I’m talking about the app’s assets
Relevant part of the apps config/prod.exs
config :bespoke_work, BespokeWork.Web.Endpoint,
on_init: {BespokeWork.Web.Endpoint, :load_from_system_env, []},
http: [port: {:system, "PORT"}],
url: [scheme: "https", host: System.get_env("HEROKU_HOST"), port: System.get_env("HEROKU_PORT")],
static_url: [scheme: "https", host: System.get_env("STATIC_ASSETS"), port: 443],
force_ssl: [rewrite_on: [:x_forwarded_proto]],
cache_static_manifest: "priv/static/cache_manifest.json",
secret_key_base: System.get_env("SECRET_KEY_BASE")```
QUESTION
-
How can I prevent Heroku from building the assets and, instead, during deploy, automatically upload the digested assets to an Amazon S3 Bucket?
-
Will that make Heroku’s slug smaller?
POSSIBLE SOLUTION
1.Reducing Heroku’s Slug Size:
• On the Procfile redirect mix phx.digest to output digested items to /dev/null.
or
• Redefine mix deps.compile for Prod, not generating the assets.
2.Generate the assets locally.
3.Either Manually upload them or use a Shell Script to upload them to S3.
4.Use static_url to generate paths “pointing” to the S3 Bucket.
• Is there any simpler way to accomplish this? •
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outlog
the biggest question is why? what problem are you trying to solve?
that said you can create a custom compile script for your assets.. where I suppose you can do the normal assets compilation/digesting - then upload to s3 and then rm the compiled assets dir - GitHub - gjaldon/heroku-buildpack-phoenix-static: A Heroku buildpack for building Phoenix's static assets · GitHub
but I would warn against this, it accomplishes close to nothing, and adds a lot of complexity.
also don’t use s3 as a cdn, it’s not really optimized for that.
static_url+cloudfront takes no time to set up, and is what I would recommend.
btw: you are already using cloudflare cdn which is working fine (look for cf-cache-status:HIT)
jaysoifer
Problem: Heroku’s Slug Size Limitation (300 mb).
I have to upload a lot of big images (>5 mb/ea.) to this project and this limit is really low.
Regarding the CDN: yes, I’m already using CloudFlare, the question mentions that.
jaysoifer
This is what I’m considering right now:
• One possible solution is to use a CI/CD environment like Codeship to automate the deployment process, including the Amazon S3 part (and setup scripts, and tests, and what have you).
• This doesn’t fix the Heroku Slug size limitation (which is already big). It maybe interesting to consider alternative way of storing those assets like a database.
outlog
ok, that is a very special use case, that goes beyond ‘normal’ assets.
without knowing anything about these images (can the app server start with no images, how does it reference the images etc - what is their life cycle - create/update/delete)
my best guess is go for ‘admin uploaded’ images eg. store them on s3 with references to them in a db table (most likely using arc | Hex + ex_aws).
Also note that heroku has a 1gb limit on your git repo size.
jaysoifer
So I just talked to the really nice guys @ Heroku and here is the deal:
.slugignorefile for basic use cases (like .pdf or .psd)and / or
outlog
create a custom mix task that uploads your assets to s3, then rm them from the slug.. call the mix task in your custom compile file.. heroku-buildpack-phoenix-static/compile at master · gjaldon/heroku-buildpack-phoenix-static · GitHub
just remember the 1gb limit that heroku has. Limits | Heroku Dev Center