When I compile my Snap webapp (to deploy it to production server), it comes out to 19MB! What gives? Is this normal? Am I doing something wrong?
My site only has 3 static pages, basically snap's init project.
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Is this somehow a problem? Would using shared libraries make you feel better? – Thomas M. DuBuisson Jul 03 '12 at 05:01
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Well, I have to upload 20MB over slow `scp` connection to my EC2 instance every time I want to make a tiny change... – Andriy Drozdyuk Jul 03 '12 at 05:06
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1So it sounds like you should use shared Libraries to cut out the duplication. – Thomas M. DuBuisson Jul 03 '12 at 05:34
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2@ThomasM.DuBuisson: Could you expand that into an answer please? – Tikhon Jelvis Jul 03 '12 at 05:42
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[Making small haskell executables?](http://stackoverflow.com/questions/699908/making-small-haskell-executables) – hal Jul 03 '12 at 05:47
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2Or you could compress the executable with `xz` before the transfer and decompress it afterwards... or in one pass with `xz -c9 a.out | ssh -v ec2-host.amazon.com "xz -cd > a.out"`. That reduces a simple hello world app from 16MB to 1.6MB on my box. – Nathan Howell Jul 03 '12 at 07:55
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@hal Thanks, but those answers are quite OLD! – Andriy Drozdyuk Jul 03 '12 at 12:54
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@drozzy The answers in [the question linked by hal's question](http://stackoverflow.com/questions/6115459/small-haskell-program-compiled-with-ghc-into-huge-binary) aren't. – Daniel Wagner Jul 03 '12 at 13:13
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I guess Snap pulls a lot of dependencies. One solution to this problem, which unfortunately affects the (initial) compilation time is to install libraries your project depend on with --split-objs option. That will generate a ton of different object but will make the final executable a lot smaller, like 2-4 times smaller.
$ cabal install --enable-split-objs
If you already have the libraries installed you will need to remove them first, install a fresh GHC or use sandbox with it's own package set.
You should also use strip command (cabal does this automatically in some cases).
Additionally you may consider using upx for compressing executables and finally rsync to upload minimally different executable to the server.
Using shared libraries (cabal install --enable-shared) may or may not help here: I didn't experiment with that option.
Tener
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Should I do this both on the local server and on the production? Or just ensuring that production has Haskell is sufficient? – Andriy Drozdyuk Jul 04 '12 at 01:21
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I tried both `--enable-split-objs` and `--enabled-shared` on my snap project and neither one seems to work. The binary is exactly the same size. – Andriy Drozdyuk Jul 04 '12 at 03:31
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@drozzy You need to build the libraries that your project depend on with these options. Just recompiling your project won't do much. I would recommend starting with a clean installation of GHC for this purpose or using sandboxing solution for this (like virthualenv or something). – Tener Jul 04 '12 at 10:03
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Thanks, do I then need to install GHC and all the dependencies on my production server? Have you ever used something like [bsdiff](http://www.daemonology.net/bsdiff/)? – Andriy Drozdyuk Jul 18 '12 at 18:14