helloweb: Switch to cloning helloweb.git via gowork infrastructure

- it is gowork that is now used by Go-related bits in SlapOS, so using
  gowork is preferred as example. Besides we need gowork to be able to
  use any third-party Go package.

- other languages can use helloweb repository from under gowork/ tree as
  well.

The hash of helloweb.git is changed, becuase its layout had to be too
adjusted to match gowork mode:

nexedi/helloweb@a072af78...8bfedac6

component/helloweb/buildout.cfg

@@ -4,6 +4,7 @@ extends =
   ../git/buildout.cfg
   ../ruby/buildout.cfg
   ../golang/buildout.cfg
+  gowork.cfg
 
 parts =
   helloweb-python
@@ -11,20 +12,40 @@ parts =
   helloweb-go
 
 
-# repository with examples
-[helloweb-repository]
-recipe  = slapos.recipe.build:gitclone
-git-executable = ${git:location}/bin/git
-repository = https://lab.nexedi.com/nexedi/helloweb.git
-revision = a072af789dcd3a1106b69ef4dc2a310d8daa5c48
-location = ${buildout:parts-directory}/helloweb
+# helloweb.git repository with examples.
+#
+# We clone it via golang infrastructure into a Go workspace.
+# Via gowork helloweb/go is not only cloned, but also built and installed into gowork/bin.
+#
+# Another option would be to use slapos.recipe.build:gitclone and handle
+# cloning+building manually. However to be able to use third-party Go packages
+# we need gowork support, and other languages can use helloweb repository from
+# under gowork as well.
+[gowork]
+install =
+    lab.nexedi.com/nexedi/helloweb/go/...
+
+golang  = ${golang1.11:location}
+
+
+# -*- go -*-
+[helloweb-go]
+# we already have gowork/bin/helloweb with helloweb Go build.
+# Add bin/helloweb-go that runs go version of helloweb without any environment preset needed.
+recipe  = collective.recipe.template
+output  = ${buildout:bin-directory}/${:_buildout_section_name_}
+mode    = 0755
+input   = inline:
+    #!/bin/sh
+    . ${gowork:env.sh}
+    exec helloweb "$@"
 
 
 # -*- python -*-
 [helloweb-egg]
 recipe  = zc.recipe.egg:develop
 egg     = helloweb
-setup   = ${helloweb-repository:location}/python/
+setup   = ${gowork:src}/lab.nexedi.com/nexedi/helloweb/python/
 
 [helloweb-python]
 recipe  = zc.recipe.egg:scripts
@@ -66,7 +87,7 @@ environment =
 
 [helloweb-ruby-bundle]
 recipe  = slapos.recipe.cmmi
-path    = ${helloweb-repository:location}/ruby/
+path    = ${gowork:src}/lab.nexedi.com/nexedi/helloweb/ruby/
 
 configure-command = :
 make-binary =
@@ -84,15 +105,3 @@ input   = inline:
     exec ${bundler:bundle} exec sh -c 'helloweb.rb "$@"' ${:_buildout_section_name_} "$@"
 
 
-# -*- go -*-
-[helloweb-go]
-recipe  = slapos.recipe.cmmi
-path    = ${helloweb-repository:location}/go/
-
-go      = ${golang1.11:location}/bin/go
-configure-command = :
-make-binary =
-make-targets= cd ${:path} &&
-     ${:go} build
-        -o ${buildout:bin-directory}/${:_buildout_section_name_}
-        helloweb.go

component/helloweb/gowork.cfg

+# Code generated by gowork-snapshot; DO NOT EDIT.
+
+# list of go git repositories to fetch
+[gowork.goinstall]
+depends_gitfetch  =
+    ${go_lab.nexedi.com_nexedi_helloweb:recipe}
+
+
+[go_lab.nexedi.com_nexedi_helloweb]
+<= go-git-package
+go.importpath = lab.nexedi.com/nexedi/helloweb
+repository    = https://lab.nexedi.com/nexedi/helloweb.git
+revision      = 8bfedac656