builder: move node filtering functionality

- add builder method
- allow filtering on load to simplify invocations

Signed-off-by: Ilya Dmitrichenko <errordeveloper@gmail.com>

build/build.go

@@ -112,23 +112,6 @@ type NamedContext struct {
 	State *llb.State
 }
 
-func filterAvailableNodes(nodes []builder.Node) ([]builder.Node, error) {
-	out := make([]builder.Node, 0, len(nodes))
-	err := errors.Errorf("no drivers found")
-	for _, n := range nodes {
-		if n.Err == nil && n.Driver != nil {
-			out = append(out, n)
-		}
-		if n.Err != nil {
-			err = n.Err
-		}
-	}
-	if len(out) > 0 {
-		return out, nil
-	}
-	return nil, err
-}
-
 type driverPair struct {
 	driverIndex int
 	platforms   []specs.Platform
@@ -802,11 +785,6 @@ func BuildWithResultHandler(ctx context.Context, nodes []builder.Node, opt map[s
 		return nil, errors.Errorf("driver required for build")
 	}
 
-	nodes, err = filterAvailableNodes(nodes)
-	if err != nil {
-		return nil, errors.Wrapf(err, "no valid drivers found")
-	}
-
 	var noMobyDriver driver.Driver
 	for _, n := range nodes {
 		if !n.Driver.IsMobyDriver() {

builder/node.go

@@ -34,6 +34,24 @@ func (b *Builder) Nodes() []Node {
 	return b.nodes
 }
 
+// AvailableNodes returns only nodes that are available.
+func (b *Builder) AvailableNodes() ([]Node, error) {
+	out := make([]Node, 0, len(b.nodes))
+	err := errors.Errorf("no drivers found")
+	for _, n := range b.nodes {
+		if n.Err == nil && n.Driver != nil {
+			out = append(out, n)
+		}
+		if n.Err != nil {
+			err = n.Err
+		}
+	}
+	if len(out) > 0 {
+		return out, nil
+	}
+	return nil, err
+}
+
 // LoadNodes loads and returns nodes for this builder.
 // TODO: this should be a method on a Node object and lazy load data for each driver.
 func (b *Builder) LoadNodes(ctx context.Context, withData bool) (_ []Node, err error) {
@@ -163,6 +181,15 @@ func (b *Builder) LoadNodes(ctx context.Context, withData bool) (_ []Node, err e
 	return b.nodes, nil
 }
 
+func (b *Builder) LoadAvailableNodes(ctx context.Context, withData bool) (_ []Node, err error) {
+	_, err = b.LoadNodes(ctx, withData)
+	if err != nil {
+		return nil, err
+	}
+
+	return b.AvailableNodes()
+}
+
 func (n *Node) loadData(ctx context.Context) error {
 	if n.Driver == nil {
 		return nil

commands/bake.go

@@ -114,7 +114,7 @@ func runBake(dockerCli command.Cli, targets []string, in bakeOptions) (err error
 		if err = updateLastActivity(dockerCli, b.NodeGroup); err != nil {
 			return errors.Wrapf(err, "failed to update builder last activity time")
 		}
-		nodes, err = b.LoadNodes(ctx, false)
+		nodes, err = b.LoadAvailableNodes(ctx, false)
 		if err != nil {
 			return err
 		}

commands/build.go

@@ -266,7 +266,7 @@ func runBuild(dockerCli command.Cli, in buildOptions) (err error) {
 	if err = updateLastActivity(dockerCli, b.NodeGroup); err != nil {
 		return errors.Wrapf(err, "failed to update builder last activity time")
 	}
-	nodes, err := b.LoadNodes(ctx, false)
+	nodes, err := b.LoadAvailableNodes(ctx, false)
 	if err != nil {
 		return err
 	}

commands/diskusage.go

@@ -38,15 +38,10 @@ func runDiskUsage(dockerCli command.Cli, opts duOptions) error {
 		return err
 	}
 
-	nodes, err := b.LoadNodes(ctx, false)
+	nodes, err := b.LoadAvailableNodes(ctx, false)
 	if err != nil {
 		return err
 	}
-	for _, node := range nodes {
-		if node.Err != nil {
-			return node.Err
-		}
-	}
 
 	out := make([][]*client.UsageInfo, len(nodes))
 

commands/prune.go

@@ -59,15 +59,10 @@ func runPrune(dockerCli command.Cli, opts pruneOptions) error {
 		return err
 	}
 
-	nodes, err := b.LoadNodes(ctx, false)
+	nodes, err := b.LoadAvailableNodes(ctx, false)
 	if err != nil {
 		return err
 	}
-	for _, node := range nodes {
-		if node.Err != nil {
-			return node.Err
-		}
-	}
 
 	ch := make(chan client.UsageInfo)
 	printed := make(chan struct{})