Network errors on CI

[kuisathaverat]

the following error happened twice today

[2019-09-04T07:39:27.213Z] go: finding gopkg.in/src-d/go-git-fixtures.v3 v3.3.0
[2019-09-04T07:39:31.419Z] verifying go.elastic.co/fastjson@v1.0.0/go.mod: go.elastic.co/fastjson@v1.0.0/go.mod: Get http://proxy.invalid/sumdb/sum.golang.org/supported: dial tcp: lookup proxy.invalid on 169.254.169.254:53: no such host
[2019-09-04T07:39:31.419Z] 2019/09/04 07:39:30 exit status 1
[2019-09-04T07:39:31.419Z] exit status 1
[2019-09-04T07:39:31.419Z] Makefile:29: recipe for target 'check-modules' failed
[2019-09-04T07:39:31.419Z] make: *** [check-modules] Error 1
script returned exit code 2

[kuisathaverat]

Could be the same in elastic/apm-server#2673

[kuisathaverat]

it is a different issue, it could be related to the Go version, failed stages are using 1.13

[kuisathaverat]

testing it locally I got a different error

verifying github.com/grpc-ecosystem/go-grpc-middleware@v1.0.0: checksum mismatch
	downloaded: h1:BWIsLfhgKhV5g/oF34aRjniBHLTZe5DNekSjbAjIS6c=
	go.sum:     h1:Iju5GlWwrvL6UBg4zJJt3btmonfrMlCDdsejg4CZE7c=

SECURITY ERROR
This download does NOT match an earlier download recorded in go.sum.
The bits may have been replaced on the origin server, or an attacker may
have intercepted the download attempt.

For more information, see 'go help module-auth'.

[kuisathaverat]

maybe related to this two new env vars https://golang.org/doc/go1.13

The new GOSUMDB environment variable identifies the name, and optionally the public key and server URL, of the database to consult for checksums of modules that are not yet listed in the main module's go.sum file. If GOSUMDB does not include an explicit URL, the URL is chosen by probing the GOPROXY URLs for an endpoint indicating support for the checksum database, falling back to a direct connection to the named database if it is not supported by any proxy. If GOSUMDB is set to off, the checksum database is not consulted and only the existing checksums in the go.sum file are verified.

Users who cannot reach the default proxy and checksum database (for example, due to a firewalled or sandboxed configuration) may disable their use by setting GOPROXY to direct, and/or GOSUMDB to off. go env -w can be used to set the default values for these variables independent of platform:

go env -w GOPROXY=direct
go env -w GOSUMDB=off

[axw]

@kuisathaverat this was fixed by #629

[axw]

(At least I'm pretty sure it was. Please reopen if it not.)