Cleanup build script

[cuonglm]

Build release script assumes GNU toolchains to make it works, thus running the script under Mac OSX fails. There're two problems:

• date command invocation using GNU specific parameters.
• Incorrect handling of checksum command invocation.

To fix them:

• Use common parameters of both GNU date and BSD date, also use a specific time format form, instead of relying on --iso-8601 GNU option. This will change the timezone offset format from +00:00 to +0000.
• Use an array to handle checksum command invocation.

While at it, also add -trimpath to all go build and go install command.

[codecov-io]

Codecov Report

Merging #1245 into master will decrease coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1245      +/-   ##
==========================================
- Coverage    75.3%   75.28%   -0.02%     
==========================================
  Files         149      149              
  Lines       10841    10841              
==========================================
- Hits         8164     8162       -2     
- Misses       2210     2212       +2     
  Partials      467      467

Impacted Files	Coverage Δ
stats/cloud/collector.go	76.99% <0%> (-0.62%)	⬇️

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[na--]

Ah, actually, can you add -trimpath in these places as well:
https://github.com/loadimpact/k6/blob/5f12764462a93260eee80d88c749d30552e18749/appveyor.yml#L55
https://github.com/loadimpact/k6/blob/5f12764462a93260eee80d88c749d30552e18749/.circleci/config.yml#L142

And update the PR title and description, since it's fixing more things than the MacOS incompatibilities... 😊

[imiric]

LGTM

It's a shame we can't rely on GNU tools, as find dist -type f | parallel ... would cleanup and speed up the checksum generation (assuming our CI is multi-core). But maybe we can standardize on GNU tools once we move away from Circle and automate these builds.

[cuonglm]

LGTM

It's a shame we can't rely on GNU tools, as find dist -type f | parallel ... would cleanup and speed up the checksum generation (assuming our CI is multi-core). But maybe we can standardize on GNU tools once we move away from Circle and automate these builds.

You don't need parallel for this task, use xargs instead. But that won't work though, concurrently append to file with >> will make the file content corrupted.

[imiric]

You don't need parallel for this task, use xargs instead.

Ah, but which variant of xargs? ;) Do they all support -P? Also, see man parallel_alternatives. parallel is just nicer to use, though I agree that it's over-engineered (SQL support, remote execution).

But that won't work though, concurrently append to file with >> will make the file content corrupted.

Hhmm true. Would this solve it?

find dist -type f -printf '%P\n' | parallel sha256sum > checksums.txt

In any case, parallelizing this likely won't matter much as a) this script won't be run frequently, and b) there's not a lot of artifacts to checksum, and it's a quick operation anyway.

It would still be good to standardize on a single toolchain, and it should be possible once this is automated.

[cuonglm]

Ah, but which variant of xargs? ;) Do they all support -P?

both GNU and BSD xargs.

find dist -type f -printf '%P\n' | parallel sha256sum > checksums.txt

It's just the same. The output won't be mixed, but they will be out of order.

It would still be good to standardize on a single toolchain, and it should be possible once this is automated.

I disagree. We shouldn't rely on any toolchain specific features if we can avoid, instead, sticking to POSIX standard, which will be available in all compliant systems. In our case, they're Linux and Mac (BSD). The thing is that for standard utilities, if you write a script which works on BSD, it will be likely working on GNU system as well, but not vice versa.

I invite you to read https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.69/html_node/Portable-Shell.html, it's not target POSIX, but it will help you write portable shell script in a better way.