[management, reverse proxy] Add reverse proxy feature (#5291)

* implement reverse proxy


---------

Co-authored-by: Alisdair MacLeod <git@alisdairmacleod.co.uk>
Co-authored-by: mlsmaycon <mlsmaycon@gmail.com>
Co-authored-by: Eduard Gert <kontakt@eduardgert.de>
Co-authored-by: Viktor Liu <viktor@netbird.io>
Co-authored-by: Diego Noguês <diego.sure@gmail.com>
Co-authored-by: Diego Noguês <49420+diegocn@users.noreply.github.com>
Co-authored-by: Bethuel Mmbaga <bethuelmbaga12@gmail.com>
Co-authored-by: Zoltan Papp <zoltan.pmail@gmail.com>
Co-authored-by: Ashley Mensah <ashleyamo982@gmail.com>

proxy/internal/proxy/context.go

@@ -0,0 +1,187 @@
+package proxy
+
+import (
+	"context"
+	"sync"
+
+	"github.com/netbirdio/netbird/proxy/internal/types"
+)
+
+type requestContextKey string
+
+const (
+	serviceIdKey    requestContextKey = "serviceId"
+	accountIdKey    requestContextKey = "accountId"
+	capturedDataKey requestContextKey = "capturedData"
+)
+
+// ResponseOrigin indicates where a response was generated.
+type ResponseOrigin int
+
+const (
+	// OriginBackend means the response came from the backend service.
+	OriginBackend ResponseOrigin = iota
+	// OriginNoRoute means the proxy had no matching host or path.
+	OriginNoRoute
+	// OriginProxyError means the proxy failed to reach the backend.
+	OriginProxyError
+	// OriginAuth means the proxy intercepted the request for authentication.
+	OriginAuth
+)
+
+func (o ResponseOrigin) String() string {
+	switch o {
+	case OriginNoRoute:
+		return "no_route"
+	case OriginProxyError:
+		return "proxy_error"
+	case OriginAuth:
+		return "auth"
+	default:
+		return "backend"
+	}
+}
+
+// CapturedData is a mutable struct that allows downstream handlers
+// to pass data back up the middleware chain.
+type CapturedData struct {
+	mu         sync.RWMutex
+	RequestID  string
+	ServiceId  string
+	AccountId  types.AccountID
+	Origin     ResponseOrigin
+	ClientIP   string
+	UserID     string
+	AuthMethod string
+}
+
+// GetRequestID safely gets the request ID
+func (c *CapturedData) GetRequestID() string {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	return c.RequestID
+}
+
+// SetServiceId safely sets the service ID
+func (c *CapturedData) SetServiceId(serviceId string) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.ServiceId = serviceId
+}
+
+// GetServiceId safely gets the service ID
+func (c *CapturedData) GetServiceId() string {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	return c.ServiceId
+}
+
+// SetAccountId safely sets the account ID
+func (c *CapturedData) SetAccountId(accountId types.AccountID) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.AccountId = accountId
+}
+
+// GetAccountId safely gets the account ID
+func (c *CapturedData) GetAccountId() types.AccountID {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	return c.AccountId
+}
+
+// SetOrigin safely sets the response origin
+func (c *CapturedData) SetOrigin(origin ResponseOrigin) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.Origin = origin
+}
+
+// GetOrigin safely gets the response origin
+func (c *CapturedData) GetOrigin() ResponseOrigin {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	return c.Origin
+}
+
+// SetClientIP safely sets the resolved client IP.
+func (c *CapturedData) SetClientIP(ip string) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.ClientIP = ip
+}
+
+// GetClientIP safely gets the resolved client IP.
+func (c *CapturedData) GetClientIP() string {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	return c.ClientIP
+}
+
+// SetUserID safely sets the authenticated user ID.
+func (c *CapturedData) SetUserID(userID string) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.UserID = userID
+}
+
+// GetUserID safely gets the authenticated user ID.
+func (c *CapturedData) GetUserID() string {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	return c.UserID
+}
+
+// SetAuthMethod safely sets the authentication method used.
+func (c *CapturedData) SetAuthMethod(method string) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.AuthMethod = method
+}
+
+// GetAuthMethod safely gets the authentication method used.
+func (c *CapturedData) GetAuthMethod() string {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	return c.AuthMethod
+}
+
+// WithCapturedData adds a CapturedData struct to the context
+func WithCapturedData(ctx context.Context, data *CapturedData) context.Context {
+	return context.WithValue(ctx, capturedDataKey, data)
+}
+
+// CapturedDataFromContext retrieves the CapturedData from context
+func CapturedDataFromContext(ctx context.Context) *CapturedData {
+	v := ctx.Value(capturedDataKey)
+	data, ok := v.(*CapturedData)
+	if !ok {
+		return nil
+	}
+	return data
+}
+
+func withServiceId(ctx context.Context, serviceId string) context.Context {
+	return context.WithValue(ctx, serviceIdKey, serviceId)
+}
+
+func ServiceIdFromContext(ctx context.Context) string {
+	v := ctx.Value(serviceIdKey)
+	serviceId, ok := v.(string)
+	if !ok {
+		return ""
+	}
+	return serviceId
+}
+func withAccountId(ctx context.Context, accountId types.AccountID) context.Context {
+	return context.WithValue(ctx, accountIdKey, accountId)
+}
+
+func AccountIdFromContext(ctx context.Context) types.AccountID {
+	v := ctx.Value(accountIdKey)
+	accountId, ok := v.(types.AccountID)
+	if !ok {
+		return ""
+	}
+	return accountId
+}