Add stub database selection, and fix differences between pekoe and c-redis

- PUBSUB CHANNELS glob pattern matching
- Implement SELECT + max DB validation (0-15) (default db max is 16), for perl clients
- CLIENT KILL ID (single/range) + MAXAGE
- CLIENT INFO events + resp fields
- PUBSUB SHARDCHANNELS/SHARDNUMSUB stubs

internal/glob/glob.go

@@ -0,0 +1,58 @@
+// @tag glob
+package glob
+
+// Match checks if a string matches a glob-style pattern.
+// Supports:
+//   - * (asterisk): matches any sequence of characters (including empty)
+//   - ? (question): matches any single character
+//
+// This matches Redis PUBSUB CHANNELS pattern behavior.
+func Match(pattern, s string) bool {
+	if pattern == "" {
+		return s == ""
+	}
+	if pattern == "*" {
+		return true
+	}
+
+	// Simple glob matching using dynamic programming
+	// Convert pattern to regex-like matching
+	patternLen := len(pattern)
+	sLen := len(s)
+
+	// dp[i][j] = true if pattern[0:i] matches s[0:j]
+	dp := make([][]bool, patternLen+1)
+	for i := range dp {
+		dp[i] = make([]bool, sLen+1)
+	}
+
+	// Empty pattern matches empty string
+	dp[0][0] = true
+
+	// Handle leading * in pattern
+	for i := 1; i <= patternLen; i++ {
+		if pattern[i-1] == '*' {
+			dp[i][0] = dp[i-1][0]
+		}
+	}
+
+	// Fill the DP table
+	for i := 1; i <= patternLen; i++ {
+		for j := 1; j <= sLen; j++ {
+			switch pattern[i-1] {
+			case '*':
+				// * matches: either consume nothing (stay at same position in pattern)
+				// or consume one character from string
+				dp[i][j] = dp[i-1][j] || dp[i][j-1]
+			case '?':
+				// ? matches any single character
+				dp[i][j] = dp[i-1][j-1]
+			default:
+				// Literal character must match exactly
+				dp[i][j] = dp[i-1][j-1] && pattern[i-1] == s[j-1]
+			}
+		}
+	}
+
+	return dp[patternLen][sLen]
+}

internal/glob/glob_test.go

@@ -0,0 +1,69 @@
+// @tag glob
+// @tag test
+package glob
+
+import "testing"
+
+func TestMatch(t *testing.T) {
+	tests := []struct {
+		pattern string
+		s       string
+		want    bool
+	}{
+		{"", "", true},
+		{"", "foo", false},
+		{"*", "", true},
+		{"*", "foo", true},
+		{"*", "foo/bar", true},
+		{"foo", "foo", true},
+		{"foo", "bar", false},
+		{"foo*", "foo", true},
+		{"foo*", "foobar", true},
+		{"foo*", "fo", false},
+		{"*foo", "foo", true},
+		{"*foo", "barfoo", true},
+		{"*foo", "bar", false},
+		{"foo*bar", "foobar", true},
+		{"foo*bar", "foobazbar", true},
+		{"foo*bar", "foobaz", false},
+		{"foo?bar", "fooXbar", true},
+		{"foo?bar", "fooXXbar", false},
+		{"foo??bar", "fooXXbar", true},
+		{"?", "a", true},
+		{"?", "", false},
+		{"a?c", "abc", true},
+		{"a?c", "ac", false},
+		{"foo?*bar", "fooabcbar", true},
+		{"foo?*bar", "foobar", false},
+		{"*foo*bar*", "ahellofoocherrybarb", true},
+		{"ch*", "channel", true},
+		{"ch*", "ch", true},
+		{"ch*", "c", false},
+		{"*", "*", true},
+		{"**", "*", true},
+		{"*a*b", "aXb", true},
+		{"a*b*c", "aXbYc", true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.pattern+"/"+tt.s, func(t *testing.T) {
+			if got := Match(tt.pattern, tt.s); got != tt.want {
+				t.Errorf("Match(%q, %q) = %v, want %v", tt.pattern, tt.s, got, tt.want)
+			}
+		})
+	}
+}
+
+func BenchmarkMatch(b *testing.B) {
+	patterns := []string{"*", "ch*", "foo*bar", "???", "*channel*"}
+	strings := []string{"channel", "channel123", "foobar", "abc", "somechannelname"}
+
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		for _, p := range patterns {
+			for _, s := range strings {
+				Match(p, s)
+			}
+		}
+	}
+}

internal/pubsub/client.go

@@ -31,6 +31,7 @@ type Client struct {
 	conn       net.Conn
 	name       string    // Connection name set via CLIENT SETNAME
 	replyMode  ReplyMode // Reply mode (ON/OFF/SKIP)
+	selectedDB int       // Selected database index (via SELECT command)
 	flags      uint64    // Client flags (e.g., paused, no-touch)
 	created    time.Time // When the client connected
 	lastActive time.Time // Last activity time
@@ -48,6 +49,7 @@ func NewClient(conn net.Conn) *Client {
 		conn:       conn,
 		name:       "",
 		replyMode:  ReplyOn,
+		selectedDB: 0,
 		flags:      0,
 		created:    now,
 		lastActive: now,
@@ -89,6 +91,27 @@ func (c *Client) GetReplyMode() ReplyMode {
 	return c.replyMode
 }
 
+// SelectedDB returns the currently selected database index
+func (c *Client) SelectedDB() int {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	return c.selectedDB
+}
+
+// CreatedAt returns when the client connected
+func (c *Client) CreatedAt() time.Time {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	return c.created
+}
+
+// SetSelectedDB sets the selected database index
+func (c *Client) SetSelectedDB(db int) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.selectedDB = db
+}
+
 // UpdateActivity updates the last activity timestamp
 func (c *Client) UpdateActivity() {
 	c.mu.Lock()
@@ -212,7 +235,7 @@ func (c *Client) LocalAddr() string {
 }
 
 // InfoString returns CLIENT INFO formatted string (Redis format)
-// Format: id= addr= laddr= fd= age= idle= flags= db= sub= psub= multi= qbuf= qbuf-free= obl= oll= omem= tot-mem= cmd= user= redir=
+// Format: id= addr= laddr= fd= age= idle= flags= db= sub= psub= multi= qbuf= qbuf-free= obl= oll= omem= tot-mem= events= cmd= user= redir= resp=
 func (c *Client) InfoString() string {
 	c.mu.RLock()
 	defer c.mu.RUnlock()
@@ -229,16 +252,21 @@ func (c *Client) InfoString() string {
 		flags += "S"
 	}
 
+	// Events - indicate connection is active for read and write
+	events := "rw"
+
 	// Format: Redis CLIENT INFO format
-	return fmt.Sprintf("id=%d addr=%s laddr=%s fd=-1 age=%d idle=%d flags=%s db=0 sub=%d psub=%d multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 tot-mem=0 cmd=client user=default redir=-1",
+	return fmt.Sprintf("id=%d addr=%s laddr=%s fd=-1 age=%d idle=%d flags=%s db=%d sub=%d psub=%d multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 tot-mem=0 events=%s cmd=client user=default redir=-1 resp=2",
 		c.id,
 		c.RemoteAddr(),
 		c.LocalAddr(),
 		age,
 		idle,
 		flags,
+		c.selectedDB,
 		len(c.subscribed),
 		len(c.patterns),
+		events,
 	)
 }
 

internal/server/handlers.go

@@ -5,7 +5,9 @@ package server
 import (
 	"fmt"
 	"strings"
+	"time"
 
+	"github.com/eleksir/pekoe/internal/glob"
 	"github.com/eleksir/pekoe/internal/logger"
 	"github.com/eleksir/pekoe/internal/protocol"
 	"github.com/eleksir/pekoe/internal/pubsub"
@@ -132,12 +134,24 @@ func (s *Server) handlePubsub(args [][]byte, writer *ConnWriter) error {
 			pattern = string(args[1])
 		}
 		channels := s.channelList(pattern)
-		result := make([]protocol.Value, len(channels))
+		result := make([]protocol.Value, 0, len(channels))
-		for i, ch := range channels {
+		for _, ch := range channels {
-			result[i] = protocol.Bulk(ch)
+			if pattern == "" || glob.Match(pattern, ch) {
+				result = append(result, protocol.Bulk(ch))
+			}
 		}
 		writer.WriteArray(result)
 
+	case "shardchannels":
+		// PUBSUB SHARDCHANNELS [pattern] - List active sharded channels
+		// Pekoe doesn't support sharded pubsub, return empty list
+		writer.WriteArray(nil)
+
+	case "shardnumsub":
+		// PUBSUB SHARDNUMSUB [shardchannel ...] - Get subscriber count for sharded channels
+		// Pekoe doesn't support sharded pubsub, return empty array
+		writer.WriteArray(nil)
+
 	case "numpat":
 		// PUBSUB NUMPAT - Count of unique pattern subscriptions
 		writer.WriteInt(int64(s.hub.PatternCount()))
@@ -147,7 +161,9 @@ func (s *Server) handlePubsub(args [][]byte, writer *ConnWriter) error {
 		helpText := []string{
 			"PUBSUB <subcommand> [<argument> [<argument> ...]]>",
 			"  PUBSUB CHANNELS [pattern] - List active channels (optionally filtered by pattern)",
+			"  PUBSUB SHARDCHANNELS [pattern] - List active sharded channels (not supported)",
 			"  PUBSUB NUMSUB [channel ...] - Get subscriber count for channels",
+			"  PUBSUB SHARDNUMSUB [shardchannel ...] - Get subscriber count for sharded channels (not supported)",
 			"  PUBSUB NUMPAT - Get the number of pattern subscriptions",
 			"  PUBSUB HELP - Show this help message",
 		}
@@ -349,11 +365,15 @@ func (s *Server) buildClientList(args [][]byte) string {
 func (s *Server) handleClientKill(currentClient *pubsub.Client, args [][]byte) (int, error) {
 	clients := s.hub.GetAllClients()
 	killed := 0
+	var notFoundErr error
 
 	// Parse arguments
 	var killID uint64
+	var killIDMin uint64
+	var killIDMax uint64
 	var killAddr string
 	var skipMe = true
+	var maxAgeMs int64
 
 	for i := 0; i < len(args); i++ {
 		arg := strings.ToUpper(string(args[i]))
@@ -361,6 +381,12 @@ func (s *Server) handleClientKill(currentClient *pubsub.Client, args [][]byte) (
 		case "ID":
 			if i+2 < len(args) {
 				// ID min max format - kill all IDs in range
+				if _, err := fmt.Sscanf(string(args[i+1]), "%d", &killIDMin); err != nil {
+					return 0, fmt.Errorf("invalid client ID: %s", args[i+1])
+				}
+				if _, err := fmt.Sscanf(string(args[i+2]), "%d", &killIDMax); err != nil {
+					return 0, fmt.Errorf("invalid client ID: %s", args[i+2])
+				}
 				i += 2
 			} else if i+1 < len(args) {
 				// Single ID
@@ -374,14 +400,35 @@ func (s *Server) handleClientKill(currentClient *pubsub.Client, args [][]byte) (
 				killAddr = string(args[i+1])
 				i++
 			}
+		case "LADDR":
+			// LADDR not fully supported, just skip
+			if i+1 < len(args) {
+				i++
+			}
 		case "SKIPME":
 			if i+1 < len(args) {
 				skipMe = strings.ToUpper(string(args[i+1])) == "YES"
 				i++
 			}
+		case "MAXAGE":
+			if i+1 < len(args) {
+				if _, err := fmt.Sscanf(string(args[i+1]), "%d", &maxAgeMs); err != nil {
+					return 0, fmt.Errorf("invalid maxage: %s", args[i+1])
+				}
+				if maxAgeMs <= 0 {
+					return 0, fmt.Errorf("maxage must be greater than 0")
+				}
+				i++
+			}
+		case "TYPE":
+			// TYPE filter handled separately in handleClient
+			if i+1 < len(args) {
+				i++
+			}
 		}
 	}
 
+	now := time.Now()
 	for _, c := range clients {
 		// Skip current client if requested
 		if skipMe && c.ID() == currentClient.ID() {
@@ -390,11 +437,29 @@ func (s *Server) handleClientKill(currentClient *pubsub.Client, args [][]byte) (
 
 		shouldKill := false
 
-		if killID > 0 && c.ID() == killID {
+		// Check ID (single or range)
+		if killID > 0 {
+			shouldKill = c.ID() == killID
+		} else if killIDMin > 0 || killIDMax > 0 {
+			id := c.ID()
+			if killIDMin > 0 && id < killIDMin {
+				shouldKill = false
+			} else if killIDMax > 0 && id > killIDMax {
+				shouldKill = false
+			} else {
 				shouldKill = true
 			}
-		if killAddr != "" && c.RemoteAddr() == killAddr {
+		}
-			shouldKill = true
+
+		// Check ADDR
+		if !shouldKill && killAddr != "" {
+			shouldKill = c.RemoteAddr() == killAddr
+		}
+
+		// Check MAXAGE
+		if shouldKill && maxAgeMs > 0 {
+			age := now.Sub(c.CreatedAt()).Milliseconds()
+			shouldKill = age >= maxAgeMs
 		}
 
 		if shouldKill {
@@ -406,7 +471,39 @@ func (s *Server) handleClientKill(currentClient *pubsub.Client, args [][]byte) (
 		}
 	}
 
-	return killed, nil
+	// For single ID/ADDR that wasn't found, Redis returns error
+	if killed == 0 && (killID > 0 || killAddr != "") {
+		return 0, fmt.Errorf("No such client")
+	}
+
+	return killed, notFoundErr
+}
+
+// handleSelect processes SELECT command.
+// SELECT db - Switch to a different database (0-15).
+// For pekoe (pubsub-only), this only tracks the selected DB for client compatibility.
+// Redis default max DB is 16 (0-15), configurable via max-databases in config.
+func (s *Server) handleSelect(client *pubsub.Client, args [][]byte, writer *ConnWriter) error {
+	if len(args) != 1 {
+		writer.WriteError("ERR wrong number of arguments for 'select' command")
+		return nil
+	}
+
+	dbIndexStr := string(args[0])
+	var dbIndex int
+	if _, err := fmt.Sscanf(dbIndexStr, "%d", &dbIndex); err != nil {
+		writer.WriteError("ERR invalid DB index")
+		return nil
+	}
+
+	if dbIndex < 0 || dbIndex >= MaxDatabases {
+		writer.WriteError("ERR DB index is out of range")
+		return nil
+	}
+
+	client.SetSelectedDB(dbIndex)
+	writer.WriteStatus("OK")
+	return nil
 }
 
 // handlePsubscribe processes PSUBSCRIBE command.

internal/server/server.go

@@ -21,6 +21,8 @@ import (
 	"github.com/eleksir/pekoe/internal/pubsub"
 )
 
+const MaxDatabases = 16 // Redis default maximum databases (0-15)
+
 // Sentinel errors for connection handling
 var (
 	ErrQuit = errors.New("client quit")
@@ -276,6 +278,8 @@ func (s *Server) processCommand(client *pubsub.Client, cmd *Command, writer *Con
 		return s.handleQuit(client, writer)
 	case "client":
 		return s.handleClient(client, cmd.Args[1:], writer)
+	case "select":
+		return s.handleSelect(client, cmd.Args[1:], writer)
 	default:
 		// Check if client is in pubsub mode - only pubsub commands allowed
 		if client != nil && (client.SubsCount() > 0 || client.PatternSubsCount() > 0) {