1 // Copyright 2018 Google LLC All Rights Reserved. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 package authn 16 17 type multiKeychain struct { 18 keychains []Keychain 19 } 20 21 // Assert that our multi-keychain implements Keychain. 22 var _ (Keychain) = (*multiKeychain)(nil) 23 24 // NewMultiKeychain composes a list of keychains into one new keychain. 25 func NewMultiKeychain(kcs ...Keychain) Keychain { 26 return &multiKeychain{keychains: kcs} 27 } 28 29 // Resolve implements Keychain. 30 func (mk *multiKeychain) Resolve(target Resource) (Authenticator, error) { 31 for _, kc := range mk.keychains { 32 auth, err := kc.Resolve(target) 33 if err != nil { 34 return nil, err 35 } 36 if auth != Anonymous { 37 return auth, nil 38 } 39 } 40 return Anonymous, nil 41 } 42