Go Module confusion

README.md

I have a couple of cmd apps with some imports:

cmd/monitorrules/main.go:

package main

import (
	"bufio"
	"fmt"
	"io/ioutil"
	"os"
	"sort"
	"strings"

	"github.com/lightbend/console-api/monitors"
	"gopkg.in/alecthomas/kingpin.v2"
)

...

cmd/yamltojson/main.go:

package main

import (
	"fmt"
	"io/ioutil"
	"os"

	"gopkg.in/alecthomas/kingpin.v2"
	"github.com/ghodss/yaml"
)

...

I also have a tools.go file:

// +build tools

package tools

import (
	_ "golang.org/x/lint/golint"
	_	"github.com/prometheus/prometheus/cmd/promtool@6f92ce56053866194ae5937012c1bec40f1dd1d9"
)

An empty go.mod file:

module github.com/lightbend/observability/monitors

go 1.13

Now I'm trying to figure out what the correct way is to:

1. Populate the go.mod and go.sum files.
2. On the build machine, download the tools so that the build scripts can use them.

This seems to get me part of the way there:

➜  monitors git:(generate-monitors) ✗ go get ./...
go: finding github.com/lightbend/console-api/monitors latest

go.mod:

module github.com/lightbend/observability/monitors

go 1.13

require (
	github.com/ghodss/yaml v1.0.0
	github.com/lightbend/console-api v1.2.4
	gopkg.in/alecthomas/kingpin.v2 v2.2.6
)

Ok so the imports from the cmd apps are there but not the tools.

Following https://github.com/go-modules-by-example/index/blob/master/010_tools/README.md it would seem I have to use go install.

➜  monitors git:(generate-monitors) ✗ go install golang.org/x/lint/golint

No output but exit code was 0 so I guess just carry on?

➜  monitors git:(generate-monitors) ✗ go install github.com/prometheus/prometheus/cmd/promtool@6f92ce56053866194ae5937012c1bec40f1dd1d9
can't load package: package github.com/prometheus/prometheus/cmd/promtool@6f92ce56053866194ae5937012c1bec40f1dd1d9: can only use path@version syntax with 'go get'

Oops! Hmm so no version allowed here apparently.

Hmm that's not great, going to get bit by prometheus/prometheus#5590.

Oh well...

➜  monitors git:(generate-monitors) ✗ go install github.com/prometheus/prometheus/cmd/promtool

Ummm ok that worked but it shouldn't have?

go.mod:

module github.com/lightbend/observability/monitors

go 1.13

require (
	github.com/ghodss/yaml v1.0.0
	github.com/lightbend/console-api v1.2.4
	gopkg.in/alecthomas/kingpin.v2 v2.2.6
)

Still the same.

go mod tidy

go.mod:

module github.com/lightbend/observability/monitors

go 1.13

require (
	github.com/ghodss/yaml v1.0.0
	github.com/lightbend/console-api v1.2.4
	github.com/prometheus/prometheus v0.0.0-20190525122359-d20e84d0fb64
	golang.org/x/lint v0.0.0-20190301231843-5614ed5bae6f
	gopkg.in/alecthomas/kingpin.v2 v2.2.6
)

🤨

---

➜  monitors git:(generate-monitors) ✗ rm go.sum && echo 'module github.com/lightbend/observability/monitors

go 1.13' > go.mod
➜  monitors git:(generate-monitors) ✗ go get github.com/prometheus/prometheus/cmd/promtool@6f92ce56053866194ae5937012c1bec40f1dd1d9
go: finding github.com/prometheus/prometheus/cmd/promtool 6f92ce56053866194ae5937012c1bec40f1dd1d9
go: finding github.com/prometheus 6f92ce56053866194ae5937012c1bec40f1dd1d9
go: finding github.com 6f92ce56053866194ae5937012c1bec40f1dd1d9
go: finding github.com/prometheus/prometheus 6f92ce56053866194ae5937012c1bec40f1dd1d9
go: finding github.com/prometheus/prometheus/cmd 6f92ce56053866194ae5937012c1bec40f1dd1d9
➜  monitors git:(generate-monitors) ✗ go get ./...
go: finding github.com/lightbend/console-api/monitors latest
➜  monitors git:(generate-monitors) ✗ rm go.sum && echo 'module github.com/lightbend/observability/monitors

go 1.13' > go.mod
➜  monitors git:(generate-monitors) ✗ go get ./...
go: finding github.com/lightbend/console-api/monitors latest
➜  monitors git:(generate-monitors) ✗ go get github.com/prometheus/prometheus/cmd/promtool@6f92ce56053866194ae5937012c1bec40f1dd1d9
go: finding github.com 6f92ce56053866194ae5937012c1bec40f1dd1d9
go: finding github.com/prometheus/prometheus 6f92ce56053866194ae5937012c1bec40f1dd1d9
go: finding github.com/prometheus 6f92ce56053866194ae5937012c1bec40f1dd1d9
go: finding github.com/prometheus/prometheus/cmd/promtool 6f92ce56053866194ae5937012c1bec40f1dd1d9
go: finding github.com/prometheus/prometheus/cmd 6f92ce56053866194ae5937012c1bec40f1dd1d9
# k8s.io/client-go/rest
../../../go/pkg/mod/k8s.io/[email protected]+incompatible/rest/request.go:598:31: not enough arguments in call to watch.NewStreamWatcher
	have (*versioned.Decoder)
	want (watch.Decoder, watch.Reporter)

WTF! Why does the order matter?

---

➜  monitors git:(generate-monitors) ✗ rm go.sum && echo 'module github.com/lightbend/observability/monitors

go 1.13' > go.mod
➜  monitors git:(generate-monitors) ✗ rm go.sum && echo 'module github.com/lightbend/observability/monitors\[C
➜  monitors git:(generate-monitors) ✗ go get github.com/prometheus/prometheus/cmd/promtool
go: finding github.com/google/pprof latest
go: finding github.com/prometheus/client_model latest
go: finding golang.org/x/oauth2 latest
go: finding k8s.io/api latest
go: finding k8s.io/apimachinery latest
go: finding github.com/mwitkow/go-conntrack latest
go: finding github.com/samuel/go-zookeeper latest
go: finding k8s.io/utils latest
build github.com/prometheus/prometheus/cmd/promtool: cannot load github.com/Azure/azure-sdk-for-go/arm/compute: module github.com/Azure/azure-sdk-for-go@latest (v36.1.0+incompatible) found, but does not contain package github.com/Azure/azure-sdk-for-go/arm/compute
➜  monitors git:(generate-monitors) ✗ rm go.sum && echo 'module github.com/lightbend/observability/monitors

go 1.13' > go.mod
➜  monitors git:(generate-monitors) ✗ go get ./...
go: finding github.com/lightbend/console-api/monitors latest
➜  monitors git:(generate-monitors) ✗ go get github.com/prometheus/prometheus/cmd/promtool

This time it is the reverse problem. 🤯