Rely on a locally installed copy of godep binary.

[dmitshur]

Install godep into a local .bin folder. That way, it will always be accessible even if the user does not have $GOPATH/bin added to their $PATH.

This is an implementation of the alternative idea described in #46 (comment). Review and thoughts are welcome.

Closes #46.

[dmitshur]

Note, I have not tested this Makefile yet, it is an idea up for review first. If it looks good, I'll test before merging. I do not have enough confidence in Makefile semantics to make this change blindly (perhaps the way I am setting the env variable that way is not supported, etc.).

[sqs]

You pointed out the complexity of figuring out the right cwd in the Makefile in the other PR. But does godep handle it properly? I mean, if a Makefile recipe executes godep go xyz and you run the Makefile with make -C some/other/dir, does Godep properly set GOPATH to /abspath/to/some/other/dir/Godeps/_workspace:$GOPATH or does it set it to the Godeps dir that's the nearest parent of $PWD?

[dmitshur]

I think the processes that are started via the listed commands have their current working directory set where the Makefile lives. If that weren't the case, the -o .bin/srclib-go part of go build step would not work as expected.

The problem is figuring out the current working directory as an absolute path string which can be passed as a string parameter. Namely, $GOPATH needs to be be made of absolute paths only; that was the difficulty.

I think it's best to test this and confirm it works as expected.

[dmitshur]

Ok, I've tested it (on a fresh Ubuntu live VM), it worked as expected.

I was able to reproduce the failure when $GOPATH/bin was not in my $PATH, and switching to this branch allowed the following command to succeed.

Before:

Building Go toolchain program
Running  [make -C /home/ubuntu/.srclib/sourcegraph.com/sourcegraph/srclib-go]
make: Entering directory '/home/ubuntu/.srclib/sourcegraph.com/sourcegraph/srclib-go'
go get github.com/tools/godep
godep go build -o .bin/srclib-go
make: godep: Command not found
Makefile:7: recipe for target 'install' failed
make: *** [install] Error 127
make: Leaving directory '/home/ubuntu/.srclib/sourcegraph.com/sourcegraph/srclib-go'
failed to install/upgrade Go (sourcegraph.com/sourcegraph/srclib-go) toolchain: command ["make" "-C" "/home/ubuntu/.srclib/sourcegraph.com/sourcegraph/srclib-go"] failed: exit status 2
The following toolchains were not installed:
Go (sourcegraph.com/sourcegraph/srclib-go)

After:

Building Go toolchain program
Running  [make -C /home/ubuntu/.srclib/sourcegraph.com/sourcegraph/srclib-go]
make: Entering directory '/home/ubuntu/.srclib/sourcegraph.com/sourcegraph/srclib-go'
GOBIN=.bin go get github.com/tools/godep
.bin/godep go build -o .bin/srclib-go
make: Leaving directory '/home/ubuntu/.srclib/sourcegraph.com/sourcegraph/srclib-go'
OK! Installed/upgraded Go (sourcegraph.com/sourcegraph/srclib-go) toolchain
================================================================================

[sqs]

LGTM. And wanna just remove the unused var decls at the top of the Makefile after merge?