mirror of
https://github.com/octoleo/syncthing.git
synced 2024-09-20 13:49:02 +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
109 lines
2.9 KiB
Go
109 lines
2.9 KiB
Go
// Copyright 2017 The Prometheus Authors
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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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package sysfs
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import (
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"fmt"
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"os"
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"path/filepath"
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"github.com/prometheus/procfs/bcache"
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"github.com/prometheus/procfs/xfs"
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)
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// FS represents the pseudo-filesystem sys, which provides an interface to
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// kernel data structures.
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type FS string
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// DefaultMountPoint is the common mount point of the sys filesystem.
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const DefaultMountPoint = "/sys"
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// NewFS returns a new FS mounted under the given mountPoint. It will error
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// if the mount point can't be read.
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func NewFS(mountPoint string) (FS, error) {
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info, err := os.Stat(mountPoint)
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if err != nil {
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return "", fmt.Errorf("could not read %s: %s", mountPoint, err)
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}
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if !info.IsDir() {
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return "", fmt.Errorf("mount point %s is not a directory", mountPoint)
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}
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return FS(mountPoint), nil
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}
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// Path returns the path of the given subsystem relative to the sys root.
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func (fs FS) Path(p ...string) string {
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return filepath.Join(append([]string{string(fs)}, p...)...)
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}
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// XFSStats retrieves XFS filesystem runtime statistics for each mounted XFS
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// filesystem. Only available on kernel 4.4+. On older kernels, an empty
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// slice of *xfs.Stats will be returned.
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func (fs FS) XFSStats() ([]*xfs.Stats, error) {
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matches, err := filepath.Glob(fs.Path("fs/xfs/*/stats/stats"))
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if err != nil {
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return nil, err
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}
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stats := make([]*xfs.Stats, 0, len(matches))
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for _, m := range matches {
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f, err := os.Open(m)
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if err != nil {
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return nil, err
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}
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// "*" used in glob above indicates the name of the filesystem.
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name := filepath.Base(filepath.Dir(filepath.Dir(m)))
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// File must be closed after parsing, regardless of success or
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// failure. Defer is not used because of the loop.
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s, err := xfs.ParseStats(f)
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_ = f.Close()
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if err != nil {
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return nil, err
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}
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s.Name = name
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stats = append(stats, s)
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}
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return stats, nil
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}
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// BcacheStats retrieves bcache runtime statistics for each bcache.
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func (fs FS) BcacheStats() ([]*bcache.Stats, error) {
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matches, err := filepath.Glob(fs.Path("fs/bcache/*-*"))
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if err != nil {
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return nil, err
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}
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stats := make([]*bcache.Stats, 0, len(matches))
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for _, uuidPath := range matches {
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// "*-*" in glob above indicates the name of the bcache.
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name := filepath.Base(uuidPath)
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// stats
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s, err := bcache.GetStats(uuidPath)
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if err != nil {
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return nil, err
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}
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s.Name = name
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stats = append(stats, s)
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}
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return stats, nil
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}
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