Add GNU gettext

[codingjoe]

gettext is commonly used in various frameworks and
programming languages to provide support for i18n. Such as

• Python/Django
• Ruby/translation
• Python/flask-babel
• ... may more.

I does not make sense to have it available in side the runtime dyno, but during build time, it is helpful to have the package available to compile gettext po files (to mo).

There are already some buildpacks doing that, but since this is a GNU tool, it makes sense to have it in the main image.

[codingjoe]

@tt what needs to be done to get this thing on the road? Anything I can do?

[ojacobson]

Hi, and thanks for the contribution!

One question. Putting the actual gettext package here will install the headers and the required .so files in the heroku-16-build image, but not in the heroku-16 image. The library will be available at build-time only. Is this intended?

[codingjoe]

Yes, one should compile gettext files only during deploy not during runtime.

[dmathieu]

@codingjoe could you give us the size of the package when installed?

[codingjoe]

@codingjoe could you give us the size of the package when installed?
@dmathieu what's the recommended why to measure that? Only package or including dependencies?

[edmorley]

The Travis script outputs the image sizes to the log to help with decisions like these :-)

master:

• heroku/heroku:16 461MB
• heroku/heroku:16-build 852MB

HEAD~2 (this PR's parent until it's rebased) which doesn't have #89:

• heroku/heroku:16 460MB
• heroku/heroku:16-build 851MB

This PR:

• heroku/heroku:16 461MB
• heroku/heroku:16-build 858MB

[codingjoe]

6MB than, thanks @ojacobson
How often/When do you release new images?

[dmathieu]

@codingjoe we release stack images when required. It just happens that we're releasing one today (without your patch).
We could release again next week though. I'd like to get some else from @heroku/build to approve the PR though.

[dmathieu]

ping @dzuelke too.
WDYT? Especially about having it only in -dev?

[codingjoe]

@codingjoe we release stack images when required. It just happens that we're releasing one today (without your patch).
We could release again next week though. I'd like to get some else from @heroku/build to approve the PR though.

sounds cool, always a pleasure to work with you guys 🥇

[dzuelke]

Yeah the dev-only part is fine @dmathieu. Really all that's needed is msgfmt but we can only install the entire package. I suppose many people still produce .mo files locally and check them into version control, but thinking about it, it actually makes sense to do so at build time.

[codingjoe]

I suppose many people still produce .mo files locally and check them into version control, but thinking about it, it actually makes sense to do so at build time.

My point exactly 👍

[codingjoe]

Awesome, docker works. How long does it take until the new image is available during the regular buildpack builds?

[dmathieu]

I'll let you know here once I've finished updating the stack image.

[dmathieu]

It's out: https://devcenter.heroku.com/changelog-items/1356

[codingjoe]

Nice, I do get a msgfmt: Command not found but I guess I just need to wait a bit.

[dmathieu]

Yes, not all instances have finished updating yet. That'll be done in the next couple of hours.

[codingjoe]

I still get make: msgfmt: Command not found even after two days. I call msgfmt from post_compile inside the Python buildpack :/

[dmathieu]

@codingjoe we're aware of the issue which is not related to your patch. We're working on it and will let you know once the stack image is shipped again.

[dmathieu]

@codingjoe sorry for the delay here. gettext should be available now.

[codingjoe]

🎉 I can confirm it works 👍