Set version to unknown if not set

[danielnelson]

Prevents setting the branch version to the last major release, and as a bonus we no longer need to set this variable on release:

$ go build -ldflags "-X main.version=1.8.0 -X main.commit=fa08656a -X main.branch=default-version" ./cmd/telegraf
$ ./telegraf version
Telegraf 1.8.0 (git: default-version fa08656a)

$ go build -ldflags " -X main.commit=fa08656a -X main.branch=default-version" ./cmd/telegraf
$ ./telegraf version
Telegraf unknown (git: default-version fa08656a)

$ go build ./cmd/telegraf
$ ./telegraf version
Telegraf unknown

closes #4516

Required for all PRs:

• Signed CLA.
• Associated README.md updated.
• Has appropriate unit tests.

[kaspergrubbe]

Wouldn't it be better to update the variable nextVersion to match the release tag when a release is made?

So if I checkout 1.8.1 from git then nextVersion would be set to 1.8.1.

Or did you already do this and forgot? I wonder if it is easy to automate.

I do not know your release procedures, but I guess a script like this would help you:

if tagname.nil?
  STDOUT.puts "USAGE:"
  STDOUT.puts "To tag: git_tag_and_push.rb tagname"
  exit 1
else
  # Update the version
  system("sed -i \"s/1.7.0/1.8.0/g\" cmd/telegraf/telegraf.go")

  # Add the new file, and commit
  system("git add cmd/telegraf/telegraf.go")
  system("git commit -m 'Update version number #{tagname}'")

  # Add the tag
  system("git tag -a #{tagname} -m 'Tagging for release: #{tagname}'")

  system("git push origin #{tagname}")
end

[danielnelson]

Wouldn't it be better to update the variable nextVersion to match the release tag when a release is made?

I think this is a valid argument but I would prefer to have one less step when it comes to preparing a release. My philosophy here is that if it isn't a release then it doesn't have a version. I highly recommend that you use the Makefile to ensure this is set automatically when building a tag.

[kaspergrubbe]

Fair enough, thanks for pointing out the Makefile, I missed the versioning that it does 👍

I noticed that the build-task in the Makefile does not include -w -s as you recommended in #4516 is that on purpose?

Thanks.

[danielnelson]

We use the ldflags in the official builds because they shrink the size of the binary, but not during development. You probably want these flags if you are not planning to use a debugger, although I'm not sure exactly how much the functionality is limited by stripping symbols.

The official releases are made using scripts/build.py, at some point I would like this script to call the Makefile to create the binaries but it's not a big priority.