minio/cmd/gateway/s3/gateway-s3-chain.go
Harshavardhana 3837d2b94b
simplify credentials handling in S3 gateway (#13373)
change credentials handling such that
prefer MINIO_* envs first if they work,
if not fallback to AWS credentials. If
they fail we fail to start anyways.
2021-10-07 15:34:01 -07:00

104 lines
3.2 KiB
Go

/*
* MinIO Object Storage (c) 2021 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 s3
import (
"fmt"
"reflect"
"github.com/minio/minio-go/v7/pkg/credentials"
)
// 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 no credentials value.
//
// 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 after IsExpired() is true.
//
// 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 []credentials.Provider
curr credentials.Provider
}
// NewChainCredentials returns a pointer to a new Credentials object
// wrapping a chain of providers.
func NewChainCredentials(providers []credentials.Provider) *credentials.Credentials {
for _, p := range providers {
if p == nil {
panic("providers cannot be uninitialized")
}
}
return credentials.New(&Chain{
Providers: append([]credentials.Provider{}, providers...),
})
}
// Retrieve returns the credentials value, returns no credentials(anonymous)
// if no credentials provider returned any value.
//
// If a provider is found with credentials, it will be cached and any calls
// to IsExpired() will return the expired state of the cached provider.
func (c *Chain) Retrieve() (credentials.Value, error) {
for _, p := range c.Providers {
creds, _ := p.Retrieve()
if creds.AccessKeyID != "" && !p.IsExpired() {
// Only return credentials that are
// available and not expired.
c.curr = p
return creds, nil
}
}
providers := make([]string, 0, len(c.Providers))
for _, p := range c.Providers {
providers = append(providers, reflect.TypeOf(p).String())
}
return credentials.Value{}, fmt.Errorf("no credentials found in %s cannot proceed", providers)
}
// 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
}