support building code outside of GOPATH for go module support

[jtnord]

If I have a project that is using Go Modules (as opposed to the old GOPATH layout) I would still like to be able to use goagen. Alas it seems goagen will not work at all unless you are using the legacy GOPATH layout.

Expected Behavior

goagen app -d ${PACKAGE_NAME}/${DESIGN_DIR} -o pkg/controller works with no error.

Actual Behavior

goagen errors with

Go source file "C:\workarea\source\github\someorg\some-repo\goagen053437807\design" not in Go workspace, adjust GOPATH C:\PATH\to\go

Steps to Reproduce the Problem (including complete and simple design if relevant)

Specifications

• goa Version: goagen v1.3.1
• Platform (Linux/Windows etc.): Windows 10

[raphael]

Thank you for the report. At this point I'm focusing on v2 and will make sure it supports Go module. I'd be happy to accept a PR that added Go module support to v1 though.

[raphael]

Go modules are now supported in v1 (thank you @tchssk!). Please open a new issue if things don't work out as expected.