feat: initial commit

internal/proxy/director/context.go

@@ -0,0 +1,60 @@
+package director
+
+import (
+	"context"
+
+	"forge.cadoles.com/cadoles/bouncer/internal/store"
+	"github.com/pkg/errors"
+)
+
+type contextKey string
+
+const (
+	contextKeyProxy  contextKey = "proxy"
+	contextKeyLayers contextKey = "layers"
+)
+
+var (
+	errContextKeyNotFound     = errors.New("context key not found")
+	errUnexpectedContextValue = errors.New("unexpected context value")
+)
+
+func withProxy(ctx context.Context, proxy *store.Proxy) context.Context {
+	return context.WithValue(ctx, contextKeyProxy, proxy)
+}
+
+func ctxProxy(ctx context.Context) (*store.Proxy, error) {
+	proxy, err := ctxValue[*store.Proxy](ctx, contextKeyProxy)
+	if err != nil {
+		return nil, errors.WithStack(err)
+	}
+
+	return proxy, nil
+}
+
+func withLayers(ctx context.Context, layers []*store.Layer) context.Context {
+	return context.WithValue(ctx, contextKeyLayers, layers)
+}
+
+func ctxLayers(ctx context.Context) ([]*store.Layer, error) {
+	layers, err := ctxValue[[]*store.Layer](ctx, contextKeyLayers)
+	if err != nil {
+		return nil, errors.WithStack(err)
+	}
+
+	return layers, nil
+}
+
+func ctxValue[T any](ctx context.Context, key contextKey) (T, error) {
+	raw := ctx.Value(key)
+	if raw == nil {
+		return *new(T), errors.WithStack(errContextKeyNotFound)
+	}
+
+	value, ok := raw.(T)
+	if !ok {
+		return *new(T), errors.WithStack(errUnexpectedContextValue)
+	}
+
+	return value, nil
+}

internal/proxy/director/director.go

@@ -0,0 +1,231 @@
+package director
+
+import (
+	"context"
+	"net/http"
+	"net/url"
+	"sort"
+
+	"forge.cadoles.com/Cadoles/go-proxy"
+	"forge.cadoles.com/Cadoles/go-proxy/wildcard"
+	"forge.cadoles.com/cadoles/bouncer/internal/store"
+	"github.com/pkg/errors"
+	"gitlab.com/wpetit/goweb/logger"
+)
+
+type Director struct {
+	proxyRepository store.ProxyRepository
+	layerRepository store.LayerRepository
+	layerRegistry   *LayerRegistry
+}
+
+func (d *Director) rewriteRequest(r *http.Request) (*http.Request, error) {
+	ctx := r.Context()
+
+	proxies, err := d.getProxies(ctx)
+	if err != nil {
+		return r, errors.WithStack(err)
+	}
+
+	var match *store.Proxy
+
+MAIN:
+	for _, p := range proxies {
+		for _, from := range p.From {
+			if matches := wildcard.Match(r.Host, from); !matches {
+				continue
+			}
+
+			match = p
+			break MAIN
+		}
+	}
+
+	if match == nil {
+		return r, nil
+	}
+
+	toURL, err := url.Parse(match.To)
+	if err != nil {
+		return r, errors.WithStack(err)
+	}
+
+	r.URL.Host = toURL.Host
+	r.URL.Scheme = toURL.Scheme
+
+	ctx = logger.With(ctx,
+		logger.F("proxy", match.Name),
+		logger.F("host", r.Host),
+		logger.F("remoteAddr", r.RemoteAddr),
+	)
+
+	ctx = withProxy(ctx, match)
+
+	layers, err := d.getLayers(ctx, match.Name)
+	if err != nil {
+		return r, errors.WithStack(err)
+	}
+
+	ctx = withLayers(ctx, layers)
+	r = r.WithContext(ctx)
+
+	return r, nil
+}
+
+func (d *Director) getProxies(ctx context.Context) ([]*store.Proxy, error) {
+	headers, err := d.proxyRepository.QueryProxy(ctx, store.WithProxyQueryEnabled(true))
+	if err != nil {
+		return nil, errors.WithStack(err)
+	}
+
+	sort.Sort(store.ByProxyWeight(headers))
+
+	proxies := make([]*store.Proxy, 0, len(headers))
+
+	for _, h := range headers {
+		if !h.Enabled {
+			continue
+		}
+
+		proxy, err := d.proxyRepository.GetProxy(ctx, h.Name)
+		if err != nil {
+			return nil, errors.WithStack(err)
+		}
+
+		proxies = append(proxies, proxy)
+	}
+
+	return proxies, nil
+}
+
+func (d *Director) getLayers(ctx context.Context, proxyName store.ProxyName) ([]*store.Layer, error) {
+	headers, err := d.layerRepository.QueryLayers(ctx, proxyName, store.WithLayerQueryEnabled(true))
+	if err != nil {
+		return nil, errors.WithStack(err)
+	}
+
+	sort.Sort(store.ByLayerWeight(headers))
+
+	layers := make([]*store.Layer, 0, len(headers))
+
+	for _, h := range headers {
+		if !h.Enabled {
+			continue
+		}
+
+		layer, err := d.layerRepository.GetLayer(ctx, proxyName, h.Name)
+		if err != nil {
+			return nil, errors.WithStack(err)
+		}
+
+		layers = append(layers, layer)
+	}
+
+	return layers, nil
+}
+
+func (d *Director) RequestTransformer() proxy.RequestTransformer {
+	return func(r *http.Request) {
+		ctx := r.Context()
+		layers, err := ctxLayers(ctx)
+		if err != nil {
+			if errors.Is(err, errContextKeyNotFound) {
+				return
+			}
+
+			logger.Error(ctx, "could not retrieve layers from context", logger.E(errors.WithStack(err)))
+
+			return
+		}
+
+		for _, layer := range layers {
+			transformerLayer, ok := d.layerRegistry.GetRequestTransformer(layer.Type)
+			if !ok {
+				continue
+			}
+
+			transformer := transformerLayer.RequestTransformer(layer)
+
+			transformer(r)
+		}
+	}
+}
+
+func (d *Director) ResponseTransformer() proxy.ResponseTransformer {
+	return func(r *http.Response) error {
+		ctx := r.Request.Context()
+		layers, err := ctxLayers(ctx)
+		if err != nil {
+			if errors.Is(err, errContextKeyNotFound) {
+				return nil
+			}
+
+			return errors.WithStack(err)
+		}
+
+		for _, layer := range layers {
+			transformerLayer, ok := d.layerRegistry.GetResponseTransformer(layer.Type)
+			if !ok {
+				continue
+			}
+
+			transformer := transformerLayer.ResponseTransformer(layer)
+
+			if err := transformer(r); err != nil {
+				return errors.WithStack(err)
+			}
+		}
+
+		return nil
+	}
+}
+
+func (d *Director) Middleware() proxy.Middleware {
+	return func(next http.Handler) http.Handler {
+		fn := func(w http.ResponseWriter, r *http.Request) {
+			r, err := d.rewriteRequest(r)
+			if err != nil {
+				logger.Error(r.Context(), "could not rewrite request", logger.E(errors.WithStack(err)))
+				http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+
+				return
+			}
+
+			ctx := r.Context()
+
+			layers, err := ctxLayers(ctx)
+			if err != nil {
+				if errors.Is(err, errContextKeyNotFound) {
+					return
+				}
+
+				logger.Error(ctx, "could not retrieve proxy and layers from context", logger.E(errors.WithStack(err)))
+				http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+
+				return
+			}
+
+			httpMiddlewares := make([]proxy.Middleware, 0)
+			for _, layer := range layers {
+				middleware, ok := d.layerRegistry.GetMiddleware(layer.Type)
+				if !ok {
+					continue
+				}
+
+				httpMiddlewares = append(httpMiddlewares, middleware.Middleware(layer))
+			}
+
+			handler := createMiddlewareChain(next, httpMiddlewares)
+
+			handler.ServeHTTP(w, r)
+		}
+
+		return http.HandlerFunc(fn)
+	}
+}
+
+func New(proxyRepository store.ProxyRepository, layerRepository store.LayerRepository, layers ...Layer) *Director {
+	registry := NewLayerRegistry(layers...)
+
+	return &Director{proxyRepository, layerRepository, registry}
+}

internal/proxy/director/layer_registry.go

@@ -0,0 +1,104 @@
+package director
+
+import (
+	"forge.cadoles.com/Cadoles/go-proxy"
+	"forge.cadoles.com/cadoles/bouncer/internal/store"
+)
+
+type Layer interface {
+	LayerType() store.LayerType
+}
+
+type MiddlewareLayer interface {
+	Layer
+	Middleware(layer *store.Layer) proxy.Middleware
+}
+
+type RequestTransformerLayer interface {
+	Layer
+	RequestTransformer(layer *store.Layer) proxy.RequestTransformer
+}
+
+type ResponseTransformerLayer interface {
+	Layer
+	ResponseTransformer(layer *store.Layer) proxy.ResponseTransformer
+}
+
+type LayerRegistry struct {
+	index map[store.LayerType]Layer
+}
+
+func (r *LayerRegistry) GetLayer(layerType store.LayerType) (Layer, bool) {
+	layer, exists := r.index[layerType]
+	if !exists {
+		return nil, false
+	}
+
+	return layer, true
+}
+
+func (r *LayerRegistry) getLayerAsAny(layerType store.LayerType) (any, bool) {
+	return r.GetLayer(layerType)
+}
+
+func (r *LayerRegistry) GetMiddleware(layerType store.LayerType) (MiddlewareLayer, bool) {
+	layer, exists := r.getLayerAsAny(layerType)
+	if !exists {
+		return nil, false
+	}
+
+	middleware, ok := layer.(MiddlewareLayer)
+	if !ok {
+		return nil, false
+	}
+
+	return middleware, true
+}
+
+func (r *LayerRegistry) GetResponseTransformer(layerType store.LayerType) (ResponseTransformerLayer, bool) {
+	layer, exists := r.getLayerAsAny(layerType)
+	if !exists {
+		return nil, false
+	}
+
+	transformer, ok := layer.(ResponseTransformerLayer)
+	if !ok {
+		return nil, false
+	}
+
+	return transformer, true
+}
+
+func (r *LayerRegistry) GetRequestTransformer(layerType store.LayerType) (RequestTransformerLayer, bool) {
+	layer, exists := r.getLayerAsAny(layerType)
+	if !exists {
+		return nil, false
+	}
+
+	transformer, ok := layer.(RequestTransformerLayer)
+	if !ok {
+		return nil, false
+	}
+
+	return transformer, true
+}
+
+func (r *LayerRegistry) Load(layers ...Layer) {
+	index := make(map[store.LayerType]Layer)
+
+	for _, l := range layers {
+		layerType := l.LayerType()
+		index[layerType] = l
+	}
+
+	r.index = index
+}
+
+func NewLayerRegistry(layers ...Layer) *LayerRegistry {
+	registry := &LayerRegistry{
+		index: make(map[store.LayerType]Layer),
+	}
+	registry.Load(layers...)
+
+	return registry
+}

internal/proxy/director/util.go

@@ -0,0 +1,18 @@
+package director
+
+import (
+	"net/http"
+
+	"forge.cadoles.com/Cadoles/go-proxy"
+	"forge.cadoles.com/Cadoles/go-proxy/util"
+)
+
+func createMiddlewareChain(handler http.Handler, middlewares []proxy.Middleware) http.Handler {
+	util.Reverse(middlewares)
+
+	for _, m := range middlewares {
+		handler = m(handler)
+	}
+
+	return handler
+}