Make unconteinerized build work on OSX

[2opremio]

@davkal PTAL

[tomwilkie]

I don't understand how this even works... surely when entering the container it tries to build something that it doesn't know about?

[2opremio]

What don't you understand? It simply names the binary based on the host
architecture/OS (for which it's also compiled).

It fixes trying to use a binary from the wrong architecture when mixing
builds in and out of the container (e.g. in an OSX host) which was being
experienced by @davkal.

From a conversation in Slack it seems @davkal may be having other problems
too, let's see if this helps.

On Wednesday, February 24, 2016, Tom Wilkie notifications@github.com
wrote:

I don't understand how this even works... surely when entering the
container it tries to build something that it doesn't know about?

—
Reply to this email directly or view it on GitHub
#1028 (comment).

[davkal]

Builds in container, and on Darwin. LGTM

[tomwilkie]

Pls hold off on this until I've had a chance to look at it, I have some concerns.

[tomwilkie]

I get this when trying to build using docker-machine on my mac:

docker run --rm -ti \
        -v /Users/twilkie/Documents/src/github.com/weaveworks/scope:/go/src/github.com/weaveworks/scope \
        -v /Users/twilkie/Documents/src/github.com/weaveworks/scope/.pkg:/go/pkg \
        --net=host \
        -e GOARCH -e GOOS -e CIRCLECI -e CIRCLE_BUILD_NUM -e CIRCLE_NODE_TOTAL \
        -e CIRCLE_NODE_INDEX -e COVERDIR -e SLOW \
        weaveworks/scope-backend-build SCOPE_VERSION=18964aa GO_BUILD_INSTALL_DEPS=-i vendor/github.com/ugorji/go/codec/codecgen/bin/codecgen_darwin_amd64
make: Entering directory '/go/src/github.com/weaveworks/scope'
make: *** No rule to make target 'vendor/github.com/ugorji/go/codec/codecgen/bin/codecgen_darwin_amd64'.  Stop.
make: Leaving directory '/go/src/github.com/weaveworks/scope'
make: *** [vendor/github.com/ugorji/go/codec/codecgen/bin/codecgen_darwin_amd64] Error 2

[2opremio]

@tomwilkie please take another look. I fixed it by moving all the codecgen dependencies to the non-containerized part (which is here they should be since codecgen depends on the host of whatever runs the non-containerized part)

[tomwilkie]

This now requires I have go installed, which I thought we'd decided against...

[2opremio]

This now requires I have go installed, which I thought we'd decided against...

No it doesn't. Have you actually tested it?

As I already said, the makefile variables are used lazily unless assigned with :=, although I can happily define the variable in the non-containerized-block if that's confusing.

vagrant@vagrant-ubuntu-vivid-64:~/scope$ echo $PATH
/home/vagrant/bin:/usr/local/go/bin:/home/vagrant/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games
vagrant@vagrant-ubuntu-vivid-64:~/scope$ export PATH=/home/vagrant/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games
vagrant@vagrant-ubuntu-vivid-64:~/scope$ which go
vagrant@vagrant-ubuntu-vivid-64:~/scope$ make

[davkal]

@2opremio how did you test the darwin build? Which command do you run?

[2opremio]

@davkal I have been relying on you to test the build in Darwin (I use a Linux VM). The purpose of this PR is to make you comfortable with the build, hence the PTAL :)

[tomwilkie]

This command used to work make report/report.codecgen.go (on my mac, building in a container) but now does not.

Also, if I change the build container the .codecgen.go files are not rebuilt and I kinda think they should be.

In general it makes me uncomfortable to have different dependancy trees inside the container to outside.

[tomwilkie]

Note both of these are minor issues. What precisely is the problem we're trying to solve here?

[tomwilkie]

I cant think of a nicer way of doing this, so assuming we still want to fix the build-in-container-then-build-on-a-mac-without-a-make-clean-inbetween problem, I'm LGTM.

[2opremio]

@davkal / @foot You would still like to have this, right?

[foot]

Yes please, easier it is to build in and out of container the better!

[2opremio]

Yes please, easier it is to build in and out of container the better!

Alright, then I will rebase the changes and ask you to take another look

[2opremio]

Rebased.

@foot Can you please test it so that we can merge it? (Ideally before it bit-rots again! :) )

[foot]

env -u doesn't work on osx! grrr.
Linux: env -u GOARCH -u GOOS $(GO)
Darwin equiv: unset GOARCH GOOS; $(GO)

• Made a quick patch for the above.
• I also made a mess when rebasing onto master, i think i fixed it though, look okay?
• I have a new file now: vendor/github.com/ugorji/go/codec/codecgen/codecgen, should this be gitignored?

[foot]

But otherwise it works nicely!

[foot]

Rebased onto master.

[foot]

But circle is giving a funny permission error now so maybe i broke something..

[2opremio]

I have a new file now: vendor/github.com/ugorji/go/codec/codecgen/codecgen, should this be gitignored?

That's because we now build vendor/github.com/ugorji/go/codec/codecgen/codecgen_OS_ARCH instead. Just remove the file manually (you will only need to do this once).

[2opremio]

I think we were overcomplicating it. My last commit makes it much simpler (although it will only work when ugorji/go#148 is merged and we bump the dependency).

• Get rid of GO15VENDOREXPERIMENT since it's enabled by default in Go >=1.6,
  just use go 1.6 if you want to build outside the container.
• Stop using unset/env -u, just avoid adding env variables where needed.
• Pass build flags consistently to codecgen.
• Let the experimental/ directory be.

[foot]

LGTM for me!