Use Go modules

[nbutton23]

Simply ran go mod init github.com/pagerduty/go-pagerduty

Converted PagerDuty/go-pagerduty to match lowercased package nameing standards
https://blog.golang.org/package-names

Updated the github.com/Sirupsen/logrus import to current lowercase name

[nbutton23]

@stmcallister Did you get a chance to look at this?

[theckman]

Because Modules are still experimental I'd personally like to avoid adopting them until they are more stable.

[nbutton23]

Modules are used by basically every opensource go project. while its still beta (last i read they are targeting release in 1.14) its the most supported package manager out there for go. Little has changed in the actual API of modules in the last few releases, so i would say is stable.

[stmcallister]

I'm leaning toward @nbutton23 on this one. I'll take a look at this tomorrow.

[stmcallister]

@nbutton23 -- We're still discussing this a bit internally. If I understand it correctly, going to modules will require all existing projects using this library to be moved out of the $GOPATH, which means everyone's projects will break once we release. Is there a smoother way to make this transition?

[nbutton23]

@stmcallister It shouldn't break anything. Right now by default GO111MODULE is set to auto. If they are not using mods then nothing will change.

enables module-mode if any go.mod is found, even inside GOPATH. (Prior to Go 1.13, GO111MODULE=auto would never enable module-mode inside GOPATH).

https://github.com/golang/go/wiki/Modules

[stmcallister]

@nbutton23 Except that it broke for me. 😄

$ make build
go get ./...
go get: warning: modules disabled by GO111MODULE=auto in GOPATH/src;
    ignoring go.mod;
    see 'go help modules'
command/addon_install.go:6:2: case-insensitive import collision: "github.com/pagerduty/go-pagerduty" and "github.com/PagerDuty/go-pagerduty"
make: *** [build] Error 1

I'm guessing this is because the package name changed from PagerDuty to pagerduty?

[nbutton23]

Ah yeah thats not the module is self. Its the change made to match naming standards. I can pull that out. . .

[stmcallister]

@nbutton23 Yeah, I see what you're saying. However, if changing the package name at this point is going to break existing apps and negatively affect current users, we want to avoid making that change. If you go ahead and take that out, the rest of the PR looks good.

[nbutton23]

@stmcallister Done!

[stmcallister]

@nbutton23 Awesome! Thanks! LGTM.

@theckman Thanks for expressing your concern, but we've looked at this internally and have decided this is the direction we want to go with the library.

[stmcallister]

Using modules is the direction we're hoping to take the library. Also, thank you for fixing the logrus bug.