I am writing a Go command-line tool that generates some files based on templates.
The templates are located in the Git repository alongside the code for the command-line tool itself.
I wanted to allow the following:
Since this is a Go application, I went with something like:
templateRoot := filepath.Join(
os.Getenv("GOPATH"),
"src/github.com/myuser/myproject/templates",
)
But being rather new to Go, I wonder if this approach is reliable enough: is it guaranteed that my application template will always be accessible at that path ?
What if someone vendorize my application into their own project ? Does that even make sense for a command-line tool ?
Because of 2., I obviously can't/won't use go-bindata because I want to allow for the templates to be overriden if need be.
In summary: what is a good strategy to reliably refer to non-go, static files in a Go command-line tool ?
GOPATH is used for building the application. While you could look for GOPATH and check relative locations to each GOPATH entry at runtime, you can't be sure it will exist (unless of course you make it a prerequisite for running your application).
go get itself is a convenience for developers to fetch and build a go package. It relies on having a GOPATH (though there's a default now in go1.8), and GOBIN in your PATH. Many programs require extra steps not covered by the simple go tool, and have scripts or Makefiles to do the build. If you're targeting users that aren't developers, you need to provide a way to install into standard system paths anyway.
Do what any regular program would do, and use some well-known path to locate the template files. You can certainly add some logic in your program to check for a hierarchy of locations: relative to $GOPATH, relative to the binary, working directory, $HOME, etc; just provide a list of locations to the user that your program will look for templates.