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> I believe a tool like asdf would also achieve this (correct me if I'm wrong). This is true for very simple applications, where you’re just running `npm ci` o

> I believe a tool like asdf would also achieve this (correct me if I'm wrong). This is true for very simple applications, where you’re just running `npm ci` or `pip install`, but breaks down as soon as you have sophisticated dependencies with system / library requirements or dependencies (e.g. databases, caches, message brokers, queues) that are beyond the scope of asdf. Also, since you’re probably deploying containers to production, it’s useful to have a similar environment for local development so that you know what will actually happen in production.

jen20 4y ago
> since you’re probably deploying containers to production Citation needed I feel - I’d wager the number of containerized deployments pales in comparison to the number of binaries scp’d into a production host.
- jhardy54 4y ago
  I’d also be interested to know the answer! I said “probably” because the vast majority of deployments I’ve done over the past decade have been containerized, but I have no trouble believing that my experience isn’t indicative of the average.
999900000999 4y ago
Absolutely. Docker is NOT about local dev, it's about deployment. We forgot this...
- nordsieck 4y ago
  > Docker is NOT about local dev, it's about deployment. I mean... if Vagrant can be about local development, I don't see why Docker can't be about local development too.
- dns_snek 4y ago
  It can be anything you want it to be, especially inside the confines of your own setup. Do you want to quickly debug some software that relies on an older version of Postgres 9 but you don't want to clutter your host machine? Just run the following command to fetch and start an instance. With --rm flag it's going to be removed as soon as you terminate it: docker run --rm -p 5432:5432 postgres:9
  - 999900000999 4y ago
    It can be. But that was never the primary purpose of Docker. Like I can use Mac Minis as door stops, etc. Docker runs best on top of Linux. As in actually run a Linux host , everything else in my experience is a hack. As long as you have internet access, spinning up an ec2 instance to test stuff shouldn't be too hard.
throwawaylala1 4y ago
> Also, since you’re probably deploying containers to production, it’s useful to have a similar environment for local development so that you know what will actually happen in production. This such a complete and utter lie and I'm surprised people in 2022 still believe it. You do know what's happening when you run Docker on your Macbook, right? Right?
- jhardy54 4y ago
  Ignoring your tone, here’s a concrete example: I was debugging a HTML-to-PDF service that was crashing for some payloads, but I couldn’t reproduce the problem locally. I used Docker to run the application using the exact same image that was deployed to production, and was able to replicate the issue. Why? Because the PDF renderer depended on loads of finicky dependencies (e.g. linked libraries), and it turns out that the default fonts in our base image didn’t support the Unicode code points in the example payload. I couldn’t replicate this outside of Docker because I have a completely different set of linked libraries and don’t stack. Happy to answer any questions you have.
  - jayceekay 4y ago
    you always have that option though and i assumed it was a fairly common debug thing to have to do if you use docker enough. not just for the times it works (ie you find a bug between the layers) but for all the times it isn't the culprit. the other post mentioned setup, so i thought he meant they imposed presetup containers for developers to use?
- viraptor 4y ago
  > You do know what's happening when you run Docker on your Macbook, right? A Linux vm spawns a process with new namespaces - which is often exactly what happens in production as well.
brightball 4y ago
Best dev setup I've seen has been to use Docker compose for all of those dependencies, but just use asdf for the main application development. You get all the dependency wins of Docker for the peripherals but with the faster native local dev experience.

jen20 4y ago

> since you’re probably deploying containers to production Citation needed I feel - I’d wager the number of containerized deployments pales in comparison to the number of binaries scp’d into a production host.

jhardy54 4y ago
I’d also be interested to know the answer! I said “probably” because the vast majority of deployments I’ve done over the past decade have been containerized, but I have no trouble believing that my experience isn’t indicative of the average.

999900000999 4y ago

Absolutely. Docker is NOT about local dev, it's about deployment. We forgot this...

nordsieck 4y ago
> Docker is NOT about local dev, it's about deployment. I mean... if Vagrant can be about local development, I don't see why Docker can't be about local development too.
dns_snek 4y ago
It can be anything you want it to be, especially inside the confines of your own setup. Do you want to quickly debug some software that relies on an older version of Postgres 9 but you don't want to clutter your host machine? Just run the following command to fetch and start an instance. With --rm flag it's going to be removed as soon as you terminate it: docker run --rm -p 5432:5432 postgres:9
- 999900000999 4y ago
  It can be. But that was never the primary purpose of Docker. Like I can use Mac Minis as door stops, etc. Docker runs best on top of Linux. As in actually run a Linux host , everything else in my experience is a hack. As long as you have internet access, spinning up an ec2 instance to test stuff shouldn't be too hard.

throwawaylala1 4y ago

> Also, since you’re probably deploying containers to production, it’s useful to have a similar environment for local development so that you know what will actually happen in production. This such a complete and utter lie and I'm surprised people in 2022 still believe it. You do know what's happening when you run Docker on your Macbook, right? Right?

jhardy54 4y ago
Ignoring your tone, here’s a concrete example: I was debugging a HTML-to-PDF service that was crashing for some payloads, but I couldn’t reproduce the problem locally. I used Docker to run the application using the exact same image that was deployed to production, and was able to replicate the issue. Why? Because the PDF renderer depended on loads of finicky dependencies (e.g. linked libraries), and it turns out that the default fonts in our base image didn’t support the Unicode code points in the example payload. I couldn’t replicate this outside of Docker because I have a completely different set of linked libraries and don’t stack. Happy to answer any questions you have.
- jayceekay 4y ago
  you always have that option though and i assumed it was a fairly common debug thing to have to do if you use docker enough. not just for the times it works (ie you find a bug between the layers) but for all the times it isn't the culprit. the other post mentioned setup, so i thought he meant they imposed presetup containers for developers to use?
viraptor 4y ago
> You do know what's happening when you run Docker on your Macbook, right? A Linux vm spawns a process with new namespaces - which is often exactly what happens in production as well.

brightball 4y ago

Best dev setup I've seen has been to use Docker compose for all of those dependencies, but just use asdf for the main application development. You get all the dependency wins of Docker for the peripherals but with the faster native local dev experience.