snapcraft: fix build using golang 1.13+

[cjp256]

golang 1.13 and 1.14 will both fail with different errors when attempting go get commands. Since full support of go.mod is not yet available in snapcraft 3.9 (stable), this commit will disable go modules until it can be enabled (v3.10+). Modules are disabled by setting GO111MODULE=off in the build environment.

The current yaml specifies the go version in build-snaps. However, the go plugin has a property go-channel which sets the go snap version. The default value is latest/stable which is currently go 1.13. If a different version is specified in build-snaps, the go snap will be updated/overridden to the version (implicitly) specified by the go-channel. An example log snippet shows this behavior:

<snip>
go (1.12/stable) 1.12.17 from Michael Hudson-Doyle (mwhudson) installed
snapd is not logged in, snap install commands will use sudo
go 1.13.8 from Michael Hudson-Doyle (mwhudson) refreshed
<snip>

This is why the behavior probably only recently manifested itself, assuming the go snap's latest/stable was updated to point to 1.13.8. Local builds would also work if using snapcraft v3.10 or newer (found on candidate and edge channels).

In short:

• Lock in the go version to 1.13 using go-channel.

• Disable go modules until properly supported by snapcraft (v3.10+) using GO111MODULE=off.

Signed-off-by: Chris Patterson chris.patterson@canonical.com

How can you test this?

I tested on build.snapcraft.io using: https://github.com/cjp256/worker/commit/e54cb08d4a439d96933b09300e76219050c350ca

With a build log: https://build.snapcraft.io/user/cjp256/worker/850763

The build log shows that it builds, but does not release because I can't release your snap :wink:

[pavel-d]

@cjp256, thanks for the fix!