dotnetcore-buildpack Reduce publish slug size

@jincod As I am also having an issue of large slug size similar to #19 , I have implemented logic to reduce the slug size when publish to heroku. In my case, the slug size is reduced from 470MB to 81MB.

It is done by publishing a self-contained dotnet app instead of embedding the whole dotnet core runtime into the slug, hence the great reduction in size. See if you could accept this PR, thanks 😄

Sep 06 '17 12:09 karlwancl

Thank you for working on this! Slug size has been an issue for me as well.

Sep 06 '17 23:09 stavro

Hi @lppkarl

Many thanks for your contribution!

I'll review it.

Sep 10 '17 08:09 jincod

@lppkarl I've tried this but it still outputs a .dll (which can't be executed) - is there some additional config i need to change in my project?

Sep 12 '17 15:09 chrisanderton

@chrisanderton Maybe you have targeted a wrong framework? The publish command generates executable (with no extension) only when you're targeting netcoreapp instead of netstandard

Sep 13 '17 05:09 karlwancl

hmm @lppkarl i'm targeting netcoreapp1.1 - but tbh i'm not so strong on dotnet - does this only work with 2.0?

Sep 15 '17 20:09 chrisanderton

@chrisanderton As I see it, --self-contained tag only works for netcoreapp2.0, you may migrate your project from 1.1 to 2.0. See https://docs.microsoft.com/en-us/aspnet/core/migration/1x-to-2x/ 😄

Sep 16 '17 04:09 karlwancl

@lppkarl , I'm currently using your pull request link for buildpack and it reduces my heroku app slug size from 430MB to 40MB. My app is .net core app 2.0. Great works!

Oct 15 '17 05:10 toannguyen83

Hi @lppkarl

Would be great to do this feature optional export SELF_CONTAINED=${SELF_CONTAINED:-false} for example. Could you please implement it?

Also I've added env var DOTNET_SKIP_FIRST_TIME_EXPERIENCE (https://github.com/jincod/dotnetcore-buildpack/blob/master/bin/compile#L28) which helps to reduce slug size.

Nov 12 '17 04:11 jincod

@jincod ya, I could help implement it.

I'm interested in how DOTNET_SKIP_FIRST_TIME_EXPERIENCE help reduces slug size? Is there a mechanism for heroku to cache its installation files or restored file so that the process is not done again for second time onwards?

Nov 12 '17 13:11 karlwancl

Hi @lppkarl

Thanka a lot! Ping me if you have any questions.

DOTNET_SKIP_FIRST_TIME_EXPERIENCE dotnet core cli option. You can find more info here http://www.erikschierboom.com/2017/03/21/continuous-integration-of-dotnet-core-applications/

Nov 12 '17 14:11 jincod