mirror of
https://github.com/octoleo/syncthing.git
synced 2024-11-19 11:35:10 +00:00
916ec63af6
This is a new revision of the discovery server. Relevant changes and non-changes: - Protocol towards clients is unchanged. - Recommended large scale design is still to be deployed nehind nginx (I tested, and it's still a lot faster at terminating TLS). - Database backend is leveldb again, only. It scales enough, is easy to setup, and we don't need any backend to take care of. - Server supports replication. This is a simple TCP channel - protect it with a firewall when deploying over the internet. (We deploy this within the same datacenter, and with firewall.) Any incoming client announces are sent over the replication channel(s) to other peer discosrvs. Incoming replication changes are applied to the database as if they came from clients, but without the TLS/certificate overhead. - Metrics are exposed using the prometheus library, when enabled. - The database values and replication protocol is protobuf, because JSON was quite CPU intensive when I tried that and benchmarked it. - The "Retry-After" value for failed lookups gets slowly increased from a default of 120 seconds, by 5 seconds for each failed lookup, independently by each discosrv. This lowers the query load over time for clients that are never seen. The Retry-After maxes out at 3600 after a couple of weeks of this increase. The number of failed lookups is stored in the database, now and then (avoiding making each lookup a database put). All in all this means clients can be pointed towards a cluster using just multiple A / AAAA records to gain both load sharing and redundancy (if one is down, clients will talk to the remaining ones). GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4648
90 lines
2.9 KiB
Go
90 lines
2.9 KiB
Go
/*
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* Minio Go Library for Amazon S3 Compatible Cloud Storage
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* Copyright 2017 Minio, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package credentials
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// A Chain will search for a provider which returns credentials
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// and cache that provider until Retrieve is called again.
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//
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// The Chain provides a way of chaining multiple providers together
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// which will pick the first available using priority order of the
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// Providers in the list.
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//
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// If none of the Providers retrieve valid credentials Value, ChainProvider's
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// Retrieve() will return the no credentials value.
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//
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// If a Provider is found which returns valid credentials Value ChainProvider
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// will cache that Provider for all calls to IsExpired(), until Retrieve is
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// called again after IsExpired() is true.
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//
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// creds := credentials.NewChainCredentials(
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// []credentials.Provider{
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// &credentials.EnvAWSS3{},
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// &credentials.EnvMinio{},
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// })
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//
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// // Usage of ChainCredentials.
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// mc, err := minio.NewWithCredentials(endpoint, creds, secure, "us-east-1")
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// if err != nil {
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// log.Fatalln(err)
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// }
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//
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type Chain struct {
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Providers []Provider
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curr Provider
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}
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// NewChainCredentials returns a pointer to a new Credentials object
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// wrapping a chain of providers.
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func NewChainCredentials(providers []Provider) *Credentials {
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return New(&Chain{
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Providers: append([]Provider{}, providers...),
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})
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}
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// Retrieve returns the credentials value, returns no credentials(anonymous)
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// if no credentials provider returned any value.
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//
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// If a provider is found with credentials, it will be cached and any calls
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// to IsExpired() will return the expired state of the cached provider.
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func (c *Chain) Retrieve() (Value, error) {
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for _, p := range c.Providers {
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creds, _ := p.Retrieve()
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// Always prioritize non-anonymous providers, if any.
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if creds.AccessKeyID == "" && creds.SecretAccessKey == "" {
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continue
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}
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c.curr = p
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return creds, nil
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}
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// At this point we have exhausted all the providers and
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// are left without any credentials return anonymous.
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return Value{
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SignerType: SignatureAnonymous,
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}, nil
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}
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// IsExpired will returned the expired state of the currently cached provider
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// if there is one. If there is no current provider, true will be returned.
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func (c *Chain) IsExpired() bool {
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if c.curr != nil {
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return c.curr.IsExpired()
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}
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return true
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}
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