Refactor instance node handling to use a map

pkg/instance/instance.go

@@ -193,8 +193,10 @@ func (i *Instance) GetProxy() (*httputil.ReverseProxy, error) {
 
 	// Remote instances should not use local proxy - they are handled by RemoteInstanceProxy
 	opts := i.GetOptions()
-	if opts != nil && len(opts.Nodes) > 0 && opts.Nodes[0] != i.localNodeName {
-		return nil, fmt.Errorf("instance %s is a remote instance and should not use local proxy", i.Name)
+	if opts != nil && len(opts.Nodes) > 0 {
+		if _, isLocal := opts.Nodes[i.localNodeName]; !isLocal {
+			return nil, fmt.Errorf("instance %s is a remote instance and should not use local proxy", i.Name)
+		}
 	}
 
 	return i.proxy.GetProxy()
@@ -303,8 +305,8 @@ func (i *Instance) IsRemote() bool {
 		return false
 	}
 
-	// If the first node is the local node, treat it as a local instance
-	if opts.Nodes[0] == i.localNodeName {
+	// If the local node is in the nodes map, treat it as a local instance
+	if _, isLocal := opts.Nodes[i.localNodeName]; isLocal {
 		return false
 	}
 

pkg/instance/instance_test.go

@@ -209,7 +209,7 @@ func TestSetOptions_PreservesNodes(t *testing.T) {
 	// Create instance with initial nodes
 	initialOptions := &instance.Options{
 		BackendType: backends.BackendTypeLlamaCpp,
-		Nodes:       []string{"worker1"},
+		Nodes:       map[string]struct{}{"worker1": {}},
 		LlamaServerOptions: &llamacpp.LlamaServerOptions{
 			Model: "/path/to/model.gguf",
 			Port:  8080,
@@ -222,7 +222,7 @@ func TestSetOptions_PreservesNodes(t *testing.T) {
 	// Try to update with different nodes
 	updatedOptions := &instance.Options{
 		BackendType: backends.BackendTypeLlamaCpp,
-		Nodes:       []string{"worker2"}, // Attempt to change node
+		Nodes:       map[string]struct{}{"worker2": {}}, // Attempt to change node
 		LlamaServerOptions: &llamacpp.LlamaServerOptions{
 			Model: "/path/to/new-model.gguf",
 			Port:  8081,
@@ -233,8 +233,8 @@ func TestSetOptions_PreservesNodes(t *testing.T) {
 	opts := inst.GetOptions()
 
 	// Nodes should remain unchanged
-	if len(opts.Nodes) != 1 || opts.Nodes[0] != "worker1" {
-		t.Errorf("Expected nodes to remain ['worker1'], got %v", opts.Nodes)
+	if _, exists := opts.Nodes["worker1"]; len(opts.Nodes) != 1 || !exists {
+		t.Errorf("Expected nodes to contain 'worker1', got %v", opts.Nodes)
 	}
 
 	// Other options should be updated

pkg/instance/options.go

@@ -10,6 +10,7 @@ import (
 	"llamactl/pkg/config"
 	"log"
 	"maps"
+	"slices"
 	"sync"
 )
 
@@ -29,7 +30,7 @@ type Options struct {
 	BackendType    backends.BackendType `json:"backend_type"`
 	BackendOptions map[string]any       `json:"backend_options,omitempty"`
 
-	Nodes []string `json:"nodes,omitempty"`
+	Nodes map[string]struct{} `json:"-"`
 
 	// Backend-specific options
 	LlamaServerOptions *llamacpp.LlamaServerOptions `json:"-"`
@@ -87,6 +88,7 @@ func (c *Options) UnmarshalJSON(data []byte) error {
 	// Use anonymous struct to avoid recursion
 	type Alias Options
 	aux := &struct {
+		Nodes []string `json:"nodes,omitempty"` // Accept JSON array
 		*Alias
 	}{
 		Alias: (*Alias)(c),
@@ -96,6 +98,14 @@ func (c *Options) UnmarshalJSON(data []byte) error {
 		return err
 	}
 
+	// Convert nodes array to map
+	if len(aux.Nodes) > 0 {
+		c.Nodes = make(map[string]struct{}, len(aux.Nodes))
+		for _, node := range aux.Nodes {
+			c.Nodes[node] = struct{}{}
+		}
+	}
+
 	// Parse backend-specific options
 	switch c.BackendType {
 	case backends.BackendTypeLlamaCpp:
@@ -147,11 +157,22 @@ func (c *Options) MarshalJSON() ([]byte, error) {
 	// Use anonymous struct to avoid recursion
 	type Alias Options
 	aux := struct {
+		Nodes []string `json:"nodes,omitempty"` // Output as JSON array
 		*Alias
 	}{
 		Alias: (*Alias)(c),
 	}
 
+	// Convert nodes map to array (sorted for consistency)
+	if len(c.Nodes) > 0 {
+		aux.Nodes = make([]string, 0, len(c.Nodes))
+		for node := range c.Nodes {
+			aux.Nodes = append(aux.Nodes, node)
+		}
+		// Sort for consistent output
+		slices.Sort(aux.Nodes)
+	}
+
 	// Convert backend-specific options back to BackendOptions map for JSON
 	switch c.BackendType {
 	case backends.BackendTypeLlamaCpp: