Add lua support.

[yajo]

Following #28 (comment), there you have Lua support for 1.6+.

It must be Lua >= 5.3, so I cannot use system packages for now. Debian and Alpine have older packaged versions.

@Tecnativa

[yosifkit]

Very nice work. Looks like we can get Lua 5.3 from jessie-backports, so we can just swap the Debian Dockerfiles to be from debian:jessie-backports and grab liblua5.3-dev in the buildDeps and lua5.3 in the first apt line at the top.

[yajo]

Cool, done

[lasley]

Nice 👍

[JayH5]

On Debian you'll need LUA_INC=/usr/include/lua5.3/ added to the make command to get it to link. You'll probably also want liblua5.3-0 as the runtime dependency to get the Lua libraries, not the lua5.3 package which is just the (statically-linked?) Lua interpreter.

[tianon]

Yeah, there are a few other minor changes that need to be made too (whitespace, cleanup), which I've got locally in progress. 👍

Thanks @yajo!

[tianon]

... and of course, today http://www.haproxy.org decides that it should refuse our connections 😢

[tianon]

Seems to be the same issue as in https://www.mail-archive.com/haproxy@formilux.org/msg24512.html

[ryansch]

@tianon Appears to be working now.

[tianon]

Rough size comparisons, for reference:

• 1.7-alpine: from ~13.8MB to ~14.6MB
• 1.7: from ~138MB to ~134.9MB (yes, legitimately smaller image with Lua included -- I did a --no-cache build twice on both before and after to make sure I wasn't seeing things)
• 1.6-alpine: from ~12.91MB to ~13.62MB
• 1.6: from ~137MB to ~133.8MB (yep, smaller here too)

[yajo]

I don't know why this (I have seen it below too a few times). Is it for adding a white line? Did you know Dockerfile's white/comment lines are ignored?

[yosifkit]

Yes, we like to have some whitespace to separate sections of the RUN line. The Dockerfile parser does currently ignore empty lines, but it was "fixed" to not do so in moby/moby#24725 and reverted because of moby/moby#29005 in moby/moby#29064, but still planned to be deprecated with moby/moby#29161. As far as I know, comments in RUN lines will stay even if empty lines get removed.

[yosifkit]

I see why it got smaller! You switched to wget and it doesn't leave behind stuff after the apt-get purge -y --auto-remove like curl does. 🎉