pax_global_header00006660000000000000000000000064127536405450014525gustar00rootroot0000000000000052 comment=07dd2e8dfe18522e9c447ba95f2fe95262f63bb2 probing-0.0.1/000077500000000000000000000000001275364054500131635ustar00rootroot00000000000000probing-0.0.1/.gitignore000066400000000000000000000004121275364054500151500ustar00rootroot00000000000000# Compiled Object files, Static and Dynamic libs (Shared Objects) *.o *.a *.so # Folders _obj _test # Architecture specific extensions/prefixes *.[568vq] [568vq].out *.cgo1.go *.cgo2.c _cgo_defun.c _cgo_gotypes.go _cgo_export.* _testmain.go *.exe *.test *.prof probing-0.0.1/LICENSE000066400000000000000000000020641275364054500141720ustar00rootroot00000000000000The MIT License (MIT) Copyright (c) 2015 Xiang Li Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. probing-0.0.1/README.md000066400000000000000000000017511275364054500144460ustar00rootroot00000000000000## Getting Started ### Install the handler We first need to serve the probing HTTP handler. ```go http.HandleFunc("/health", probing.NewHandler()) err := http.ListenAndServe(":12345", nil) if err != nil { log.Fatal("ListenAndServe: ", err) } ``` ### Start to probe Now we can start to probe the endpoint. ``` go id := "example" probingInterval = 5 * time.Second url := "http://example.com:12345/health" p.AddHTTP(id, probingInterval, url) time.Sleep(13 * time.Second) status, err := p.Status(id) fmt.Printf("Total Probing: %d, Total Loss: %d, Estimated RTT: %v, Estimated Clock Difference: %v\n", status.Total(), status.Loss(), status.SRTT(), status.ClockDiff()) // Total Probing: 2, Total Loss: 0, Estimated RTT: 320.771µs, Estimated Clock Difference: -35.869µs ``` ### TODOs: - TCP probing - UDP probing - Gossip based probing - More accurate RTT estimation - More accurate Clock difference estimation - Use a clock interface rather than the real clock probing-0.0.1/prober.go000066400000000000000000000044221275364054500150050ustar00rootroot00000000000000package probing import ( "encoding/json" "errors" "net/http" "sync" "time" ) var ( ErrNotFound = errors.New("probing: id not found") ErrExist = errors.New("probing: id exists") ) type Prober interface { AddHTTP(id string, probingInterval time.Duration, endpoints []string) error Remove(id string) error RemoveAll() Reset(id string) error Status(id string) (Status, error) } type prober struct { mu sync.Mutex targets map[string]*status tr http.RoundTripper } func NewProber(tr http.RoundTripper) Prober { p := &prober{targets: make(map[string]*status)} if tr == nil { p.tr = http.DefaultTransport } else { p.tr = tr } return p } func (p *prober) AddHTTP(id string, probingInterval time.Duration, endpoints []string) error { p.mu.Lock() defer p.mu.Unlock() if _, ok := p.targets[id]; ok { return ErrExist } s := &status{stopC: make(chan struct{})} p.targets[id] = s ticker := time.NewTicker(probingInterval) go func() { pinned := 0 for { select { case <-ticker.C: start := time.Now() req, err := http.NewRequest("GET", endpoints[pinned], nil) if err != nil { panic(err) } resp, err := p.tr.RoundTrip(req) if err != nil { s.recordFailure(err) pinned = (pinned + 1) % len(endpoints) continue } var hh Health d := json.NewDecoder(resp.Body) err = d.Decode(&hh) resp.Body.Close() if err != nil || !hh.OK { s.recordFailure(err) pinned = (pinned + 1) % len(endpoints) continue } s.record(time.Since(start), hh.Now) case <-s.stopC: ticker.Stop() return } } }() return nil } func (p *prober) Remove(id string) error { p.mu.Lock() defer p.mu.Unlock() s, ok := p.targets[id] if !ok { return ErrNotFound } close(s.stopC) delete(p.targets, id) return nil } func (p *prober) RemoveAll() { p.mu.Lock() defer p.mu.Unlock() for _, s := range p.targets { close(s.stopC) } p.targets = make(map[string]*status) } func (p *prober) Reset(id string) error { p.mu.Lock() defer p.mu.Unlock() s, ok := p.targets[id] if !ok { return ErrNotFound } s.reset() return nil } func (p *prober) Status(id string) (Status, error) { p.mu.Lock() defer p.mu.Unlock() s, ok := p.targets[id] if !ok { return nil, ErrNotFound } return s, nil } probing-0.0.1/prober_test.go000066400000000000000000000041001275364054500160350ustar00rootroot00000000000000package probing import ( "net/http/httptest" "testing" "time" ) var ( testID = "testID" ) func TestProbe(t *testing.T) { s := httptest.NewServer(NewHandler()) p := NewProber(nil) p.AddHTTP(testID, time.Millisecond, []string{s.URL}) defer p.Remove(testID) time.Sleep(100 * time.Millisecond) status, err := p.Status(testID) if err != nil { t.Fatalf("err = %v, want %v", err, nil) } if total := status.Total(); total < 50 || total > 150 { t.Fatalf("total = %v, want around %v", total, 100) } if health := status.Health(); health != true { t.Fatalf("health = %v, want %v", health, true) } // become unhealthy s.Close() time.Sleep(100 * time.Millisecond) if total := status.Total(); total < 150 || total > 250 { t.Fatalf("total = %v, want around %v", total, 200) } if loss := status.Loss(); loss < 50 || loss > 150 { t.Fatalf("loss = %v, want around %v", loss, 200) } if health := status.Health(); health != false { t.Fatalf("health = %v, want %v", health, false) } } func TestProbeReset(t *testing.T) { s := httptest.NewServer(NewHandler()) defer s.Close() p := NewProber(nil) p.AddHTTP(testID, time.Millisecond, []string{s.URL}) defer p.Remove(testID) time.Sleep(100 * time.Millisecond) status, err := p.Status(testID) if err != nil { t.Fatalf("err = %v, want %v", err, nil) } if total := status.Total(); total < 50 || total > 150 { t.Fatalf("total = %v, want around %v", total, 100) } if health := status.Health(); health != true { t.Fatalf("health = %v, want %v", health, true) } p.Reset(testID) time.Sleep(100 * time.Millisecond) if total := status.Total(); total < 50 || total > 150 { t.Fatalf("total = %v, want around %v", total, 100) } if health := status.Health(); health != true { t.Fatalf("health = %v, want %v", health, true) } } func TestProbeRemove(t *testing.T) { s := httptest.NewServer(NewHandler()) defer s.Close() p := NewProber(nil) p.AddHTTP(testID, time.Millisecond, []string{s.URL}) p.Remove(testID) _, err := p.Status(testID) if err != ErrNotFound { t.Fatalf("err = %v, want %v", err, ErrNotFound) } } probing-0.0.1/server.go000066400000000000000000000005541275364054500150240ustar00rootroot00000000000000package probing import ( "encoding/json" "net/http" "time" ) func NewHandler() http.Handler { return &httpHealth{} } type httpHealth struct { } type Health struct { OK bool Now time.Time } func (h *httpHealth) ServeHTTP(w http.ResponseWriter, r *http.Request) { health := Health{OK: true, Now: time.Now()} e := json.NewEncoder(w) e.Encode(health) } probing-0.0.1/status.go000066400000000000000000000032221275364054500150340ustar00rootroot00000000000000package probing import ( "sync" "time" ) var ( // weight factor α = 0.125 ) type Status interface { Total() int64 Loss() int64 Health() bool Err() error // Estimated smoothed round trip time SRTT() time.Duration // Estimated clock difference ClockDiff() time.Duration StopNotify() <-chan struct{} } type status struct { mu sync.Mutex srtt time.Duration total int64 loss int64 health bool err error clockdiff time.Duration stopC chan struct{} } // SRTT = (1-α) * SRTT + α * RTT func (s *status) SRTT() time.Duration { s.mu.Lock() defer s.mu.Unlock() return s.srtt } func (s *status) Total() int64 { s.mu.Lock() defer s.mu.Unlock() return s.total } func (s *status) Loss() int64 { s.mu.Lock() defer s.mu.Unlock() return s.loss } func (s *status) Health() bool { s.mu.Lock() defer s.mu.Unlock() return s.health } func (s *status) Err() error { s.mu.Lock() defer s.mu.Unlock() return s.err } func (s *status) ClockDiff() time.Duration { s.mu.Lock() defer s.mu.Unlock() return s.clockdiff } func (s *status) StopNotify() <-chan struct{} { return s.stopC } func (s *status) record(rtt time.Duration, when time.Time) { s.mu.Lock() defer s.mu.Unlock() s.total += 1 s.health = true s.srtt = time.Duration((1-α)*float64(s.srtt) + α*float64(rtt)) s.clockdiff = time.Now().Sub(when) - s.srtt/2 s.err = nil } func (s *status) recordFailure(err error) { s.mu.Lock() defer s.mu.Unlock() s.total++ s.health = false s.loss += 1 s.err = err } func (s *status) reset() { s.mu.Lock() defer s.mu.Unlock() s.srtt = 0 s.total = 0 s.loss = 0 s.health = false s.clockdiff = 0 s.err = nil }