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grpc.go
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grpc.go
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// Copyright (c) 2022 The Jaeger Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package tenancy
import (
"context"
"google.golang.org/grpc"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/metadata"
"google.golang.org/grpc/status"
)
// tenantedServerStream is a wrapper for ServerStream providing settable context
type tenantedServerStream struct {
grpc.ServerStream
context context.Context
}
func (tss *tenantedServerStream) Context() context.Context {
return tss.context
}
func getValidTenant(ctx context.Context, tc *Manager) (string, error) {
// Handle case where tenant is already directly in the context
tenant := GetTenant(ctx)
if tenant != "" {
if !tc.Valid(tenant) {
return tenant, status.Errorf(codes.PermissionDenied, "unknown tenant")
}
return tenant, nil
}
// Handle case where tenant is in the context metadata
md, ok := metadata.FromIncomingContext(ctx)
if !ok {
return "", status.Errorf(codes.PermissionDenied, "missing tenant header")
}
var err error
tenant, err = tenantFromMetadata(md, tc.Header)
if err != nil {
return "", err
}
if !tc.Valid(tenant) {
return tenant, status.Errorf(codes.PermissionDenied, "unknown tenant")
}
return tenant, nil
}
func directlyAttachedTenant(ctx context.Context) bool {
return GetTenant(ctx) != ""
}
// NewGuardingStreamInterceptor blocks handling of streams whose tenancy header doesn't meet tenancy requirements.
// It also ensures the tenant is directly in the context, rather than context metadata.
func NewGuardingStreamInterceptor(tc *Manager) grpc.StreamServerInterceptor {
return func(srv any, ss grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
tenant, err := getValidTenant(ss.Context(), tc)
if err != nil {
return err
}
if directlyAttachedTenant(ss.Context()) {
return handler(srv, ss)
}
// "upgrade" the tenant to be part of the context, rather than just incoming metadata
return handler(srv, &tenantedServerStream{
ServerStream: ss,
context: WithTenant(ss.Context(), tenant),
})
}
}
func tenantFromMetadata(md metadata.MD, tenancyHeader string) (string, error) {
tenants := md.Get(tenancyHeader)
if len(tenants) < 1 {
return "", status.Errorf(codes.Unauthenticated, "missing tenant header")
} else if len(tenants) > 1 {
return "", status.Errorf(codes.PermissionDenied, "extra tenant header")
}
return tenants[0], nil
}
// NewGuardingUnaryInterceptor blocks handling of RPCs whose tenancy header doesn't meet tenancy requirements.
// It also ensures the tenant is directly in the context, rather than context metadata.
func NewGuardingUnaryInterceptor(tc *Manager) grpc.UnaryServerInterceptor {
return func(ctx context.Context, req any, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (any, error) {
tenant, err := getValidTenant(ctx, tc)
if err != nil {
return nil, err
}
if directlyAttachedTenant(ctx) {
return handler(ctx, req)
}
return handler(WithTenant(ctx, tenant), req)
}
}
// NewClientUnaryInterceptor injects tenant header into gRPC request metadata.
func NewClientUnaryInterceptor(tc *Manager) grpc.UnaryClientInterceptor {
return grpc.UnaryClientInterceptor(func(
ctx context.Context,
method string,
req, reply any,
cc *grpc.ClientConn,
invoker grpc.UnaryInvoker,
opts ...grpc.CallOption,
) error {
if tenant := GetTenant(ctx); tenant != "" {
ctx = metadata.AppendToOutgoingContext(ctx, tc.Header, tenant)
}
return invoker(ctx, method, req, reply, cc, opts...)
})
}
// NewClientStreamInterceptor injects tenant header into gRPC request metadata.
func NewClientStreamInterceptor(tc *Manager) grpc.StreamClientInterceptor {
return grpc.StreamClientInterceptor(func(
ctx context.Context,
desc *grpc.StreamDesc,
cc *grpc.ClientConn,
method string,
streamer grpc.Streamer,
opts ...grpc.CallOption,
) (grpc.ClientStream, error) {
if tenant := GetTenant(ctx); tenant != "" {
ctx = metadata.AppendToOutgoingContext(ctx, tc.Header, tenant)
}
return streamer(ctx, desc, cc, method, opts...)
})
}