Vendor dependencies with dep

vendor/github.com/minio/minio-go/pkg/credentials/chain.go

@@ -0,0 +1,89 @@
+/*
+ * Minio Go Library for Amazon S3 Compatible Cloud Storage
+ * (C) 2017 Minio, Inc.
+ *
+ * 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 credentials
+
+import "fmt"
+
+// A Chain will search for a provider which returns credentials
+// and cache that provider until Retrieve is called again.
+//
+// The Chain provides a way of chaining multiple providers together
+// which will pick the first available using priority order of the
+// Providers in the list.
+//
+// If none of the Providers retrieve valid credentials Value, ChainProvider's
+// Retrieve() will return the error, collecting all errors from all providers.
+//
+// If a Provider is found which returns valid credentials Value ChainProvider
+// will cache that Provider for all calls to IsExpired(), until Retrieve is
+// called again.
+//
+//     creds := credentials.NewChainCredentials(
+//         []credentials.Provider{
+//             &credentials.EnvAWSS3{},
+//             &credentials.EnvMinio{},
+//         })
+//
+//     // Usage of ChainCredentials.
+//     mc, err := minio.NewWithCredentials(endpoint, creds, secure, "us-east-1")
+//     if err != nil {
+//          log.Fatalln(err)
+//     }
+//
+type Chain struct {
+	Providers []Provider
+	curr      Provider
+}
+
+// NewChainCredentials returns a pointer to a new Credentials object
+// wrapping a chain of providers.
+func NewChainCredentials(providers []Provider) *Credentials {
+	return New(&Chain{
+		Providers: append([]Provider{}, providers...),
+	})
+}
+
+// Retrieve returns the credentials value or error if no provider returned
+// without error.
+//
+// If a provider is found it will be cached and any calls to IsExpired()
+// will return the expired state of the cached provider.
+func (c *Chain) Retrieve() (Value, error) {
+	var errs []error
+	for _, p := range c.Providers {
+		creds, err := p.Retrieve()
+		if err != nil {
+			errs = append(errs, err)
+			continue
+		} // Success.
+		c.curr = p
+		return creds, nil
+	}
+	c.curr = nil
+	return Value{}, fmt.Errorf("No valid providers found %v", errs)
+}
+
+// IsExpired will returned the expired state of the currently cached provider
+// if there is one.  If there is no current provider, true will be returned.
+func (c *Chain) IsExpired() bool {
+	if c.curr != nil {
+		return c.curr.IsExpired()
+	}
+
+	return true
+}