builder: move builder creation logic to builder package

This moves the builder creation logic to the builder package as we
plan to allow builder creation in the build ui of Docker Desktop so we
avoid drifting with the same logic in command package.

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

builder/builder.go

@@ -2,7 +2,9 @@ package builder
 
 import (
 	"context"
+	"encoding/csv"
 	"encoding/json"
+	"net/url"
 	"os"
 	"sort"
 	"strings"
@@ -10,12 +12,18 @@ import (
 	"time"
 
 	"github.com/docker/buildx/driver"
+	k8sutil "github.com/docker/buildx/driver/kubernetes/util"
+	remoteutil "github.com/docker/buildx/driver/remote/util"
+	"github.com/docker/buildx/localstate"
 	"github.com/docker/buildx/store"
 	"github.com/docker/buildx/store/storeutil"
+	"github.com/docker/buildx/util/confutil"
 	"github.com/docker/buildx/util/dockerutil"
 	"github.com/docker/buildx/util/imagetools"
 	"github.com/docker/buildx/util/progress"
 	"github.com/docker/cli/cli/command"
+	dopts "github.com/docker/cli/opts"
+	"github.com/google/shlex"
 	"github.com/moby/buildkit/util/progress/progressui"
 	"github.com/pkg/errors"
 	"golang.org/x/sync/errgroup"
@@ -322,3 +330,315 @@ func GetBuilders(dockerCli command.Cli, txn *store.Txn) ([]*Builder, error) {
 
 	return builders, nil
 }
+
+type CreateOpts struct {
+	Name       string
+	Driver     string
+	NodeName   string
+	Platforms  []string
+	Flags      string
+	ConfigFile string
+	DriverOpts []string
+	Use        bool
+	Endpoint   string
+	Append     bool
+}
+
+func Create(ctx context.Context, txn *store.Txn, dockerCli command.Cli, opts CreateOpts) (*Builder, error) {
+	var err error
+
+	if opts.Name == "default" {
+		return nil, errors.Errorf("default is a reserved name and cannot be used to identify builder instance")
+	} else if opts.Append && opts.Name == "" {
+		return nil, errors.Errorf("append requires a builder name")
+	}
+
+	name := opts.Name
+	if name == "" {
+		name, err = store.GenerateName(txn)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if !opts.Append {
+		contexts, err := dockerCli.ContextStore().List()
+		if err != nil {
+			return nil, err
+		}
+		for _, c := range contexts {
+			if c.Name == name {
+				return nil, errors.Errorf("instance name %q already exists as context builder", name)
+			}
+		}
+	}
+
+	ng, err := txn.NodeGroupByName(name)
+	if err != nil {
+		if os.IsNotExist(errors.Cause(err)) {
+			if opts.Append && opts.Name != "" {
+				return nil, errors.Errorf("failed to find instance %q for append", opts.Name)
+			}
+		} else {
+			return nil, err
+		}
+	}
+
+	buildkitHost := os.Getenv("BUILDKIT_HOST")
+
+	driverName := opts.Driver
+	if driverName == "" {
+		if ng != nil {
+			driverName = ng.Driver
+		} else if opts.Endpoint == "" && buildkitHost != "" {
+			driverName = "remote"
+		} else {
+			f, err := driver.GetDefaultFactory(ctx, opts.Endpoint, dockerCli.Client(), true, nil)
+			if err != nil {
+				return nil, err
+			}
+			if f == nil {
+				return nil, errors.Errorf("no valid drivers found")
+			}
+			driverName = f.Name()
+		}
+	}
+
+	if ng != nil {
+		if opts.NodeName == "" && !opts.Append {
+			return nil, errors.Errorf("existing instance for %q but no append mode, specify the node name to make changes for existing instances", name)
+		}
+		if driverName != ng.Driver {
+			return nil, errors.Errorf("existing instance for %q but has mismatched driver %q", name, ng.Driver)
+		}
+	}
+
+	if _, err := driver.GetFactory(driverName, true); err != nil {
+		return nil, err
+	}
+
+	ngOriginal := ng
+	if ngOriginal != nil {
+		ngOriginal = ngOriginal.Copy()
+	}
+
+	if ng == nil {
+		ng = &store.NodeGroup{
+			Name:   name,
+			Driver: driverName,
+		}
+	}
+
+	var flags []string
+	if opts.Flags != "" {
+		flags, err = shlex.Split(opts.Flags)
+		if err != nil {
+			return nil, errors.Wrap(err, "failed to parse buildkit flags")
+		}
+	}
+
+	var ep string
+	var setEp bool
+	switch {
+	case driverName == "kubernetes":
+		if opts.Endpoint != "" {
+			return nil, errors.Errorf("kubernetes driver does not support endpoint args %q", opts.Endpoint)
+		}
+		// generate node name if not provided to avoid duplicated endpoint
+		// error: https://github.com/docker/setup-buildx-action/issues/215
+		nodeName := opts.NodeName
+		if nodeName == "" {
+			nodeName, err = k8sutil.GenerateNodeName(name, txn)
+			if err != nil {
+				return nil, err
+			}
+		}
+		// naming endpoint to make append works
+		ep = (&url.URL{
+			Scheme: driverName,
+			Path:   "/" + name,
+			RawQuery: (&url.Values{
+				"deployment": {nodeName},
+				"kubeconfig": {os.Getenv("KUBECONFIG")},
+			}).Encode(),
+		}).String()
+		setEp = false
+	case driverName == "remote":
+		if opts.Endpoint != "" {
+			ep = opts.Endpoint
+		} else if buildkitHost != "" {
+			ep = buildkitHost
+		} else {
+			return nil, errors.Errorf("no remote endpoint provided")
+		}
+		ep, err = validateBuildkitEndpoint(ep)
+		if err != nil {
+			return nil, err
+		}
+		setEp = true
+	case opts.Endpoint != "":
+		ep, err = validateEndpoint(dockerCli, opts.Endpoint)
+		if err != nil {
+			return nil, err
+		}
+		setEp = true
+	default:
+		if dockerCli.CurrentContext() == "default" && dockerCli.DockerEndpoint().TLSData != nil {
+			return nil, errors.Errorf("could not create a builder instance with TLS data loaded from environment. Please use `docker context create <context-name>` to create a context for current environment and then create a builder instance with context set to <context-name>")
+		}
+		ep, err = dockerutil.GetCurrentEndpoint(dockerCli)
+		if err != nil {
+			return nil, err
+		}
+		setEp = false
+	}
+
+	m, err := csvToMap(opts.DriverOpts)
+	if err != nil {
+		return nil, err
+	}
+
+	configFile := opts.ConfigFile
+	if configFile == "" {
+		// if buildkit config is not provided, check if the default one is
+		// available and use it
+		if f, ok := confutil.DefaultConfigFile(dockerCli); ok {
+			configFile = f
+		}
+	}
+
+	if err := ng.Update(opts.NodeName, ep, opts.Platforms, setEp, opts.Append, flags, configFile, m); err != nil {
+		return nil, err
+	}
+
+	if err := txn.Save(ng); err != nil {
+		return nil, err
+	}
+
+	b, err := New(dockerCli,
+		WithName(ng.Name),
+		WithStore(txn),
+		WithSkippedValidation(),
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	timeoutCtx, cancel := context.WithTimeout(ctx, 20*time.Second)
+	defer cancel()
+
+	nodes, err := b.LoadNodes(timeoutCtx, WithData())
+	if err != nil {
+		return nil, err
+	}
+
+	for _, node := range nodes {
+		if err := node.Err; err != nil {
+			err := errors.Errorf("failed to initialize builder %s (%s): %s", ng.Name, node.Name, err)
+			var err2 error
+			if ngOriginal == nil {
+				err2 = txn.Remove(ng.Name)
+			} else {
+				err2 = txn.Save(ngOriginal)
+			}
+			if err2 != nil {
+				return nil, errors.Errorf("could not rollback to previous state: %s", err2)
+			}
+			return nil, err
+		}
+	}
+
+	if opts.Use && ep != "" {
+		current, err := dockerutil.GetCurrentEndpoint(dockerCli)
+		if err != nil {
+			return nil, err
+		}
+		if err := txn.SetCurrent(current, ng.Name, false, false); err != nil {
+			return nil, err
+		}
+	}
+
+	return b, nil
+}
+
+type LeaveOpts struct {
+	Name     string
+	NodeName string
+}
+
+func Leave(ctx context.Context, txn *store.Txn, dockerCli command.Cli, opts LeaveOpts) error {
+	if opts.Name == "" {
+		return errors.Errorf("leave requires instance name")
+	}
+	if opts.NodeName == "" {
+		return errors.Errorf("leave requires node name")
+	}
+
+	ng, err := txn.NodeGroupByName(opts.Name)
+	if err != nil {
+		if os.IsNotExist(errors.Cause(err)) {
+			return errors.Errorf("failed to find instance %q for leave", opts.Name)
+		}
+		return err
+	}
+
+	if err := ng.Leave(opts.NodeName); err != nil {
+		return err
+	}
+
+	ls, err := localstate.New(confutil.ConfigDir(dockerCli))
+	if err != nil {
+		return err
+	}
+	if err := ls.RemoveBuilderNode(ng.Name, opts.NodeName); err != nil {
+		return err
+	}
+
+	return txn.Save(ng)
+}
+
+func csvToMap(in []string) (map[string]string, error) {
+	if len(in) == 0 {
+		return nil, nil
+	}
+	m := make(map[string]string, len(in))
+	for _, s := range in {
+		csvReader := csv.NewReader(strings.NewReader(s))
+		fields, err := csvReader.Read()
+		if err != nil {
+			return nil, err
+		}
+		for _, v := range fields {
+			p := strings.SplitN(v, "=", 2)
+			if len(p) != 2 {
+				return nil, errors.Errorf("invalid value %q, expecting k=v", v)
+			}
+			m[p[0]] = p[1]
+		}
+	}
+	return m, nil
+}
+
+// validateEndpoint validates that endpoint is either a context or a docker host
+func validateEndpoint(dockerCli command.Cli, ep string) (string, error) {
+	dem, err := dockerutil.GetDockerEndpoint(dockerCli, ep)
+	if err == nil && dem != nil {
+		if ep == "default" {
+			return dem.Host, nil
+		}
+		return ep, nil
+	}
+	h, err := dopts.ParseHost(true, ep)
+	if err != nil {
+		return "", errors.Wrapf(err, "failed to parse endpoint %s", ep)
+	}
+	return h, nil
+}
+
+// validateBuildkitEndpoint validates that endpoint is a valid buildkit host
+func validateBuildkitEndpoint(ep string) (string, error) {
+	if err := remoteutil.IsValidEndpoint(ep); err != nil {
+		return "", err
+	}
+	return ep, nil
+}