"no local sources enabled" randomly during parallel solves

[coryb]

Using this HLB we will compile the hlb tool in parallel for Windows, Darwin and Linux:

import go from fs {
    image "openllb/go.hlb"
}

group default() {
	go.buildCommon fs {
		local "." with option {
			includePatterns "**/*.go" "go.mod" "go.sum"
		}
	} "github.com/openllb/hlb/cmd/hlb"
}

However I see the "no local sources enabled" error around 3/4 times:

$ ./hlb run ./test.hlb
[+] Building 2.1s (4/6)
 => CACHED [import go] docker-image://docker.io/openllb/go.hlb:latest                                   0.0s
 => => resolve docker.io/openllb/go.hlb:latest                                                          1.3s
 => compiling [default]                                                                                 2.0s
 => CANCELED docker-image://docker.elastic.co/beats-dev/golang-crossbuild:1.14.2-main                   0.0s
 => => resolve docker.elastic.co/beats-dev/golang-crossbuild:1.14.2-main                                0.0s
 => ERROR local://sha256:ecc4116a1fa41562e2426429f2e4b9d711f9ce72481830e244e9e0d66a32325b (**/*.go)     0.0s
 => => transferring sha256:ecc4116a1fa41562e2426429f2e4b9d711f9ce72481830e244e9e0d66a32325b:            0.0s
------
 > local://sha256:ecc4116a1fa41562e2426429f2e4b9d711f9ce72481830e244e9e0d66a32325b (**/*.go):
------
failed to solve: rpc error: code = Unknown desc = no local sources enabled

If I keep retrying it does eventually work. There is clearly a race condition and probably shared state between parallel solves, but I have not had any luck finding it yet.

[hinshun]

I thought this might be related to: moby/buildkit#2585
But I looked over the git blame and it was only introduced in July 2020, after your report in May 2020.

[coryb]

I dont recall seeing this error in a while, although I have not tried this specific build in a while. Perhaps it has been fixed.

[hinshun]

Closing for now. We can open a new issue if we see it again.