docker cli swarm package import issues

Question

Im trying to utilise docker/cli client library in my own project to create/manage stacks.

I am however facing issues building the project.

---

Code below:

package main

import (
    "fmt"
    "log"

    "github.com/docker/cli/cli/command"
    "github.com/docker/cli/cli/command/stack"
    "github.com/docker/cli/cli/flags"
)

func main() {

    cli, err := command.NewDockerCli(command.WithStandardStreams())
    if err != nil {
        log.Fatal(err)
    }

    cli.Initialize(flags.NewClientOptions())

    cmd := stack.NewStackCommand(cli)
    cmd.SetArgs([]string{"deploy", "--compose-file", "docker-compose.yml", "test"})

    err = cmd.Execute()
    if err != nil {
        log.Fatal(err)
    }

    fmt.Println("success!")
}

---

I have setup a minimal go.mod:

module github.com/dev/test

go 1.16

---

When i run go get; i get the following errors:

github.com/dev/test imports
        github.com/docker/cli/cli/command/stack imports
        github.com/docker/cli/cli/command/service imports
        github.com/docker/swarmkit/api/defaults: cannot find module providing package github.com/docker/swarmkit/api/defaults
github.com/dev/test imports
        github.com/docker/cli/cli/command/stack imports
        github.com/docker/cli/cli/command/service imports
        github.com/docker/swarmkit/api/genericresource: cannot find module providing package github.com/docker/swarmkit/api/genericresource
github.com/dev/test imports
        github.com/docker/cli/cli/command/stack imports
        github.com/docker/cli/cli/command/service imports
        github.com/docker/swarmkit/api imports
        google.golang.org/grpc/transport: cannot find module providing package google.golang.org/grpc/transport

---

I have had a deeper look into the docker/cli repo and it appears that the project does not use go modules; instead its using the older vendor dir approach.

I was wondering how i can get the project to compile. Is there a way for go get to automatically reference the packages in the vendor directory of the imported docker/cli project?

Answer 1

By default, the go command will only add the newest tagged release of a module in order to resolve a missing dependency.

According to https://github.com/docker/swarmkit/tags, the latest (and only) tagged release of github.com/docker/swarmkit was v1.12.0, back in 2016(!), and at that point in time the api/defaults and api/genericresource packages did not yet exist.

You can ask the go command for a newer-than-tagged version of a dependency by passing the commit hash or branch name explicitly for the version. For example, the latest commit as of when I am writing this comment is 2dcf70aafdc9ea55af3aaaeca440638cde0ecda6, so you could pass that commit to go get, and it seems to build properly from that point:

$ go get -d github.com/docker/swarmkit/api/...@2dcf70aafdc9ea55af3aaaeca440638cde0ecda6
go: downloading github.com/docker/swarmkit v1.12.1-0.20210611195518-2dcf70aafdc9
go: downloading github.com/coreos/etcd v0.5.0-alpha.5
go: downloading github.com/gogo/protobuf v1.3.2
go: downloading github.com/docker/go-events v0.0.0-20190806004212-e31b211e4f1c
go: downloading github.com/coreos/etcd v3.3.25+incompatible
go: downloading google.golang.org/grpc v1.38.0
go: downloading github.com/golang/protobuf v1.4.2
go: downloading golang.org/x/net v0.0.0-20201021035429-f5854403a974
go: downloading google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013
go: downloading golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f
go: downloading google.golang.org/protobuf v1.25.0
go: downloading golang.org/x/text v0.3.3
go: downloading github.com/sirupsen/logrus v1.8.1
go get: added github.com/coreos/etcd v3.3.25+incompatible
go get: added github.com/docker/go-events v0.0.0-20190806004212-e31b211e4f1c
go get: added github.com/docker/swarmkit v1.12.1-0.20210611195518-2dcf70aafdc9
go get: added github.com/gogo/protobuf v1.3.2
go get: added github.com/golang/protobuf v1.4.2
go get: added github.com/sirupsen/logrus v1.8.1
go get: added golang.org/x/net v0.0.0-20201021035429-f5854403a974
go get: added golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f
go get: added golang.org/x/text v0.3.3
go get: added google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013
go get: added google.golang.org/grpc v1.38.0
go get: added google.golang.org/protobuf v1.25.0

$ go build github.com/docker/swarmkit/api/...

$