pax_global_header00006660000000000000000000000064134175454670014532gustar00rootroot0000000000000052 comment=43a291ad63a214a207fefbf03c7d9d78b703162b probing-0.0.2/000077500000000000000000000000001341754546700131715ustar00rootroot00000000000000probing-0.0.2/.gitignore000066400000000000000000000004121341754546700151560ustar00rootroot00000000000000# 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-0.0.2/LICENSE000066400000000000000000000020641341754546700142000ustar00rootroot00000000000000The 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-0.0.2/README.md000066400000000000000000000017511341754546700144540ustar00rootroot00000000000000## 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-0.0.2/prober.go000066400000000000000000000047221341754546700150160ustar00rootroot00000000000000package probing import ( "encoding/json" "errors" "fmt" "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 && resp.StatusCode != http.StatusOK { err = fmt.Errorf("got unexpected HTTP status code %s from %s", resp.Status, endpoints[pinned]) resp.Body.Close() } 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-0.0.2/prober_test.go000066400000000000000000000041001341754546700160430ustar00rootroot00000000000000package 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-0.0.2/server.go000066400000000000000000000005541341754546700150320ustar00rootroot00000000000000package 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-0.0.2/status.go000066400000000000000000000032221341754546700150420ustar00rootroot00000000000000package 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 }