Split manager into multiple structs

pkg/manager/ports.go

@@ -0,0 +1,184 @@
+package manager
+
+import (
+	"fmt"
+	"math/bits"
+	"sync"
+)
+
+// portAllocator provides efficient port allocation using a bitmap for O(1) operations.
+// The bitmap approach prevents unbounded memory growth and simplifies port management.
+type portAllocator struct {
+	mu sync.Mutex
+
+	// Bitmap for O(1) allocation/release
+	// Each bit represents a port (1 = allocated, 0 = free)
+	bitmap []uint64 // Each uint64 covers 64 ports
+
+	// Map port to instance name for cleanup operations
+	allocated map[int]string
+
+	minPort   int
+	maxPort   int
+	rangeSize int
+}
+
+// NewPortAllocator creates a new port allocator for the given port range.
+// Returns an error if the port range is invalid.
+func NewPortAllocator(minPort, maxPort int) (*portAllocator, error) {
+	if minPort <= 0 || maxPort <= 0 {
+		return nil, fmt.Errorf("invalid port range: min=%d, max=%d (must be > 0)", minPort, maxPort)
+	}
+	if minPort > maxPort {
+		return nil, fmt.Errorf("invalid port range: min=%d > max=%d", minPort, maxPort)
+	}
+
+	rangeSize := maxPort - minPort + 1
+	bitmapSize := (rangeSize + 63) / 64 // Round up to nearest uint64
+
+	return &portAllocator{
+		bitmap:    make([]uint64, bitmapSize),
+		allocated: make(map[int]string),
+		minPort:   minPort,
+		maxPort:   maxPort,
+		rangeSize: rangeSize,
+	}, nil
+}
+
+// Allocate finds and allocates the first available port for the given instance.
+// Returns the allocated port or an error if no ports are available.
+func (p *portAllocator) Allocate(instanceName string) (int, error) {
+	if instanceName == "" {
+		return 0, fmt.Errorf("instance name cannot be empty")
+	}
+
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	port, err := p.findFirstFreeBit()
+	if err != nil {
+		return 0, err
+	}
+
+	p.setBit(port)
+	p.allocated[port] = instanceName
+
+	return port, nil
+}
+
+// AllocateSpecific allocates a specific port for the given instance.
+// Returns an error if the port is already allocated or out of range.
+func (p *portAllocator) AllocateSpecific(port int, instanceName string) error {
+	if instanceName == "" {
+		return fmt.Errorf("instance name cannot be empty")
+	}
+	if port < p.minPort || port > p.maxPort {
+		return fmt.Errorf("port %d is out of range [%d-%d]", port, p.minPort, p.maxPort)
+	}
+
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	if p.isBitSet(port) {
+		return fmt.Errorf("port %d is already allocated", port)
+	}
+
+	p.setBit(port)
+	p.allocated[port] = instanceName
+
+	return nil
+}
+
+// Release releases a specific port, making it available for reuse.
+// Returns an error if the port is not allocated.
+func (p *portAllocator) Release(port int) error {
+	if port < p.minPort || port > p.maxPort {
+		return fmt.Errorf("port %d is out of range [%d-%d]", port, p.minPort, p.maxPort)
+	}
+
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	if !p.isBitSet(port) {
+		return fmt.Errorf("port %d is not allocated", port)
+	}
+
+	p.clearBit(port)
+	delete(p.allocated, port)
+
+	return nil
+}
+
+// ReleaseByInstance releases all ports allocated to the given instance.
+// This is useful for cleanup when deleting or updating an instance.
+// Returns the number of ports released.
+func (p *portAllocator) ReleaseByInstance(instanceName string) int {
+	if instanceName == "" {
+		return 0
+	}
+
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	portsToRelease := make([]int, 0)
+	for port, name := range p.allocated {
+		if name == instanceName {
+			portsToRelease = append(portsToRelease, port)
+		}
+	}
+
+	for _, port := range portsToRelease {
+		p.clearBit(port)
+		delete(p.allocated, port)
+	}
+
+	return len(portsToRelease)
+}
+
+// --- Internal bitmap operations ---
+
+// portToBitPos converts a port number to bitmap array index and bit position.
+func (p *portAllocator) portToBitPos(port int) (index int, bit uint) {
+	offset := port - p.minPort
+	index = offset / 64
+	bit = uint(offset % 64)
+	return
+}
+
+// setBit marks a port as allocated in the bitmap.
+func (p *portAllocator) setBit(port int) {
+	index, bit := p.portToBitPos(port)
+	p.bitmap[index] |= (1 << bit)
+}
+
+// clearBit marks a port as free in the bitmap.
+func (p *portAllocator) clearBit(port int) {
+	index, bit := p.portToBitPos(port)
+	p.bitmap[index] &^= (1 << bit)
+}
+
+// isBitSet checks if a port is allocated in the bitmap.
+func (p *portAllocator) isBitSet(port int) bool {
+	index, bit := p.portToBitPos(port)
+	return (p.bitmap[index] & (1 << bit)) != 0
+}
+
+// findFirstFreeBit scans the bitmap to find the first unallocated port.
+// Returns the port number or an error if no ports are available.
+func (p *portAllocator) findFirstFreeBit() (int, error) {
+	for i, word := range p.bitmap {
+		if word != ^uint64(0) { // Not all bits are set (some ports are free)
+			// Find the first 0 bit in this word
+			// XOR with all 1s to flip bits, then find first 1 (which was 0)
+			bit := bits.TrailingZeros64(^word)
+			port := p.minPort + (i * 64) + bit
+
+			// Ensure we don't go beyond maxPort due to bitmap rounding
+			if port <= p.maxPort {
+				return port, nil
+			}
+		}
+	}
+
+	return 0, fmt.Errorf("no available ports in range [%d-%d]", p.minPort, p.maxPort)
+}