Still incredibly relevant. Even if you don’t apply it, there is so much to learn by reading this in 15 minutes.
The only grievance I have with this is Chapter 3: Config [1]
“Store config in the environment”, “Credentials to external services such as Amazon S3 or Twitter”
Besides being bad advice, this had the second-order effect of leading devs to believe they could put all their local env secrets in ~/.bashrc files.
The unwritten assumption in 12 Factor is: the environment is secure. For example, a production system should always have a secure means of setting environment variables. Said another way: If a random dev can change an environment variable in production either directly by logging in or indirectly by pushing code then there is something very very wrong.
If the dev is pushing code to production they should not simultaneously be pushing environment configs, this is doing two logically distinct things at once: Changing application behavior AND reconfiguring the server environment.
If the dev is adding secrets to their local config and they’re pushing that config to insecure places that means their deployment pipeline is broken and it should be fixed. .env is never committed to source for this reason, for example.
"The environment" is not "environment variables" and not ".env files"
For cloud services, it would typically be called a vault. But it could also be a hardware security module (HSM) with bring-your-own-key (BYOK, eg for certificates.)
Ansible also calls it a vault and encrypts it with a password — that file you can check into version control.
> this had the second-order effect of leading devs to believe they could put all their local env secrets in ~/.bashrc files
Teach them to use dotenv.
We are moving away from configuration in config files because it is a pain to modify, especially if part of that configuration is secrets. You have to throw everything into your secrets vault of preference, and editing it requires extracting and reuploading the whole thing.
We are currently doing config in env by loading one or multiple secrets per kubernetes pod (mix and match).
Every time I leave my phone in the other room to “finally get some work done”, please enter this goddamn number we sent to your SMS, and I close my laptop.
My work uses “okta verify” for everything which is very helpful, as I can sue my work PC as a trusted device or fall back to a yubikey if not. 100x better than random SMS
.env as we know is full of problems... BUT! check out varlock (https://varlock.dev) - it's free and open source, and we have really modernized and adapted the familiar syntax (a small DSL on top) to make it much better.
Has built-in validation, type-safety, composition via functions, loading with plugins, leak prevention, and much more.
I think the idea to use the environment is misguided in general.
The environment was only ever good for things like GOMAXPROCS where you want a single point of truth for all processes on a machine but in a containerized world even that point is moot. Where regular config in the environment just problematic it is outright dangerous for secrets.
Heroku seemed like it was going to be the future back then. Every time I find myself struggling to understand some nonsense in Azure I dream of the simpler future we lost.
They got painfully expensive and then acquired. I still remember the arguments with clients and finally went all in AWS ECS, which is still quite pricey but clients seem to complain less about the Amazon bill then they did about Heroku.
Its interesting how this felt so natural and right way to do software. I remember people referencing it as the north star. And then gradually people came close to it but moved past it. Personally I feel that these concepts require to have generalist mindset aka application architect. What we have as of today are lot of product engineers within teams, product managers and management. The product engineers do not always have enough leverage or incentives to push for these kind of concepts.
And still at the same time these concepts feel like so much carved in stone that one way or another everyone is going to keep discovering them again.
Is it devs that haven't internalized this? Or management? Because I'd love to do this, but I always report to people who demand that everything be done in "a few days".
Every time it gets posted I read through the list and think "export services via port binding… of course a web server binds to a port, of course it‘s decoupled that way, what else would you do" and "treat backing services as attached resources… huh, is that really only about not linking in a database, but connecting using a JDBC string, for example?"
So let me ask for once: what am I missing? Why is that interesting and not trite?
If you go far enough back in time (this dates back to at least 2011), it's arguing against things like:
For port binding, for example, it used to be that you'd deploy your app to the web application container, rather than bundling them together. e.g., deploying your WAR file to Tomcat, rather than building a self-executing JAR which included Tomcat. The wording is a bit odd, but I think they were trying to make the point very generic, and not specifically about the Enterprise Java world.
For the backing resources, it's a combination of point 3, config often living inside the codebase, applications just shelling out to /usr/sbin/sendmail or what have you, and applications living on the same host as the DB, such that bringing up a new application necessarily required bringing up a new DB as well. Which also made it hard it to scale horizontally.
The whole "12 Factor" thing was partly because Heroku had specific solutions for all of these, so going down this road made it much easier to then sell Heroku, and partly because they really were frustrating. I'd say that the port binding one is more targeted at, say, WebSphere, and all that came along with it, such as sharing a single heap across multiple apps, needing to talk to the WebSphere admins to change configuration, needing to use a "lite" version of WebSphere to test locally, if that was even possible, and so on.
They sound super-obvious these days, but at the time, for a lot of us, they were really nice to see.
The same reason many older films seem cliche - because they were the first to do it, and it's accepted standard now. Heroku very much shaped how we think of "cloud applications", autoscaling, and containerization.
I think backing services as attached resources was opposed to the practice of having your DB, and cache, and whatnot managed and maintained by a completely separate team and not really treated as part of the application. Even the schema changes.
The port binding was really a response to tomcat or modphp being modules in the webserver, as opposed to hosting their own web service internally. This was before nginx took off, and proxying to internal application ports was common.
edit:
I was wrong about the backing services, it seems it is really about treating them as configurations and being able to swap them out without making code changes.
The only grievance I have with this is Chapter 3: Config [1] “Store config in the environment”, “Credentials to external services such as Amazon S3 or Twitter”
Besides being bad advice, this had the second-order effect of leading devs to believe they could put all their local env secrets in ~/.bashrc files.
Stop doing this. Do the other 11.5 factors.
[1]: https://12factor.net/config
If the dev is pushing code to production they should not simultaneously be pushing environment configs, this is doing two logically distinct things at once: Changing application behavior AND reconfiguring the server environment.
If the dev is adding secrets to their local config and they’re pushing that config to insecure places that means their deployment pipeline is broken and it should be fixed. .env is never committed to source for this reason, for example.
For cloud services, it would typically be called a vault. But it could also be a hardware security module (HSM) with bring-your-own-key (BYOK, eg for certificates.)
Ansible also calls it a vault and encrypts it with a password — that file you can check into version control.
Teach them to use dotenv.
We are moving away from configuration in config files because it is a pain to modify, especially if part of that configuration is secrets. You have to throw everything into your secrets vault of preference, and editing it requires extracting and reuploading the whole thing.
We are currently doing config in env by loading one or multiple secrets per kubernetes pod (mix and match).
What would be your suggestion?
What makes it bad advice?
> this had the second-order effect of leading devs to believe they could put all their local env secrets in ~/.bashrc files
You need some way to pass secrets to the app; doesn't every other way also suffer the same kind of issue?
Can you explain why do you feel MFA is painful/unsustainable? How would you fix it?
Has built-in validation, type-safety, composition via functions, loading with plugins, leak prevention, and much more.
The environment was only ever good for things like GOMAXPROCS where you want a single point of truth for all processes on a machine but in a containerized world even that point is moot. Where regular config in the environment just problematic it is outright dangerous for secrets.
And still at the same time these concepts feel like so much carved in stone that one way or another everyone is going to keep discovering them again.
Tomorrow it's back to wondering why they needed 10 GUI revisions and a 65% price hike in the past year alone.
So let me ask for once: what am I missing? Why is that interesting and not trite?
For port binding, for example, it used to be that you'd deploy your app to the web application container, rather than bundling them together. e.g., deploying your WAR file to Tomcat, rather than building a self-executing JAR which included Tomcat. The wording is a bit odd, but I think they were trying to make the point very generic, and not specifically about the Enterprise Java world.
For the backing resources, it's a combination of point 3, config often living inside the codebase, applications just shelling out to /usr/sbin/sendmail or what have you, and applications living on the same host as the DB, such that bringing up a new application necessarily required bringing up a new DB as well. Which also made it hard it to scale horizontally.
The whole "12 Factor" thing was partly because Heroku had specific solutions for all of these, so going down this road made it much easier to then sell Heroku, and partly because they really were frustrating. I'd say that the port binding one is more targeted at, say, WebSphere, and all that came along with it, such as sharing a single heap across multiple apps, needing to talk to the WebSphere admins to change configuration, needing to use a "lite" version of WebSphere to test locally, if that was even possible, and so on.
They sound super-obvious these days, but at the time, for a lot of us, they were really nice to see.
The same reason many older films seem cliche - because they were the first to do it, and it's accepted standard now. Heroku very much shaped how we think of "cloud applications", autoscaling, and containerization.
The port binding was really a response to tomcat or modphp being modules in the webserver, as opposed to hosting their own web service internally. This was before nginx took off, and proxying to internal application ports was common.
edit:
I was wrong about the backing services, it seems it is really about treating them as configurations and being able to swap them out without making code changes.
https://12factor.net/backing-services
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[1]: https://forcesunseen.com/blog/stop-storing-secrets-in-enviro...
https://xkcd.com/1053/