component/caddy: make it possible to extend the workspace

by using a trailing, \ we can do in another profile:

[buildout]
extends = ../../component/caddy/buildout.cfg

[gowork]
install +=
  github.com/xxx/yyy \

component/caddy/buildout.cfg

@@ -8,8 +8,9 @@ parts =
   caddy
 
 [gowork]
+# the trailing \ is so that we can user += in other components sharing the workspace
 install =
-  github.com/mholt/caddy
+  github.com/mholt/caddy \
 
 [caddy]
 recipe  = slapos.recipe.cmmi

[Jérome Perrin]

@luke I had to do this so that to be able to "extend" the workspace with other packages here 41343688

I might be misunderstanding, but I think we have one go workspace per software release.

/cc @kirr

[Kirill Smelkov]

@jerome, thanks for heads up. Yes, gowork is only one per whole build - it is umbrella place for everything from Go land - like e.g. eggs is umbrella place for Python etc. From this point of view gowork.install is similar to buildout.parts - it is only one and global.

Regarding "" - I propose we drop it completely - please see (untested for now) nexedi/slapos!430 (merged).

[Jérome Perrin]

Yes, thanks. If this works I'll drop this commit and update the rest of the MR where it's used ( nexedi/slapos!417 (merged) )

[Łukasz Nowak]

Thanks guys :)

[Jérome Perrin]

By the way, buildout somehow supports installing different versions of eggs in different sections:

[buildout]
parts = a b

[a]
recipe = zc.recipe.egg
eggs =
  slapos.recipe.cmmi==0.8
interpreter = python-0.8

[b]
recipe = zc.recipe.egg
eggs =
  slapos.recipe.cmmi==0.7
interpreter = python-0.7

$ ./bin/buildout 
Creating directory '/tmp/xxx/eggs'.
Getting distribution for 'zc.recipe.egg>=2.0.6'.
Got zc.recipe.egg 2.0.7.
Updating a.
Getting distribution for 'slapos.recipe.cmmi==0.8'.
Got slapos.recipe.cmmi 0.8.
Getting distribution for 'slapos.recipe.build>=0.37'.
Got slapos.recipe.build 0.39.
Updating b.
Getting distribution for 'slapos.recipe.cmmi==0.7'.
Got slapos.recipe.cmmi 0.7.
$ echo "import slapos.recipe.cmmi; print slapos.recipe.cmmi" | /tmp/xxx/bin/python-0.7

>>> <module 'slapos.recipe.cmmi' from '/tmp/xxx/eggs/slapos.recipe.cmmi-0.7-py2.7.egg/slapos/recipe/cmmi/__init__.pyc'>

>>> $ 
$ echo "import slapos.recipe.cmmi; print slapos.recipe.cmmi" | /tmp/xxx/bin/python-0.8

>>> <module 'slapos.recipe.cmmi' from '/tmp/xxx/eggs/slapos.recipe.cmmi-0.8-py2.7.egg/slapos/recipe/cmmi/__init__.pyc'>

>>> $ 

I'm not sure we are relying on it though.

With go.work with don't have this flexibility. But once again, for now we don't seem to need it.

[Kirill Smelkov]

@jerome, if we ever needs this, we'll first need to upgrade gowork to support Go modules:

https://golang.org/doc/go1.11#modules
https://go.googlesource.com/proposal/+/master/design/24301-versioned-go.md