308 lines
9.6 KiB
Go
308 lines
9.6 KiB
Go
package health
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import (
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"net"
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"testing"
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"time"
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)
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func newBackend() *Backend {
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return New("web4", net.ParseIP("10.0.0.1"), 2, 3) // rise=2, fall=3
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}
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func pass() ProbeResult { return ProbeResult{OK: true, Layer: LayerL7, Code: "L7OK"} }
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func fail() ProbeResult { return ProbeResult{OK: false, Layer: LayerL4, Code: "L4CON"} }
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func TestInitialState(t *testing.T) {
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b := newBackend()
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if b.State != StateUnknown {
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t.Errorf("initial state: got %s, want unknown", b.State)
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}
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if len(b.Transitions) != 0 {
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t.Errorf("initial transitions: got %d, want 0", len(b.Transitions))
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}
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if b.Counter.Health != 0 {
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t.Errorf("initial counter health: got %d, want 0", b.Counter.Health)
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}
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}
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// TestRiseToUp: rise=2 passes from Down/Unknown → Up.
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func TestRiseToUp(t *testing.T) {
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tests := []struct {
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name string
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initialState State
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}{
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{"from unknown", StateUnknown},
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{"from down", StateDown},
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}
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for _, tt := range tests {
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t.Run(tt.name, func(t *testing.T) {
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b := newBackend()
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b.State = tt.initialState
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// First pass: counter=1, still in DOWN range (rise=2), no transition.
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if b.Record(pass(), 5) {
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t.Error("should not transition after 1 pass (rise=2)")
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}
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if b.State != tt.initialState {
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t.Errorf("state changed early: got %s", b.State)
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}
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// Second pass: counter=2=rise, transitions to Up.
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if !b.Record(pass(), 5) {
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t.Error("should transition to Up after 2 passes")
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}
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if b.State != StateUp {
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t.Errorf("state: got %s, want up", b.State)
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}
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})
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}
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}
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// TestFallToDown: fall=3 failures from fully-healthy → Down.
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//
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// The fall guarantee applies from counter=max (fully healthy). A backend that
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// just became Up is at counter=rise (the floor of the UP range), so a single
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// failure already drops it back into the DOWN range. This is correct: hysteresis
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// protects a server that has been consistently healthy for a long time, not one
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// that just scraped past the rise threshold.
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func TestFallToDown(t *testing.T) {
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b := newBackend() // rise=2, fall=3, max=4
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// Drive to fully healthy: need rise + (max-rise) = 4 passes total.
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for i := 0; i < b.Counter.Max(); i++ {
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b.Record(pass(), 5)
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}
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if b.State != StateUp {
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t.Fatalf("precondition: want up, got %s", b.State)
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}
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if b.Counter.Health != b.Counter.Max() {
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t.Fatalf("precondition: want counter=%d, got %d", b.Counter.Max(), b.Counter.Health)
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}
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// fall-1=2 failures: counter 4→3→2, both still in UP range (>=rise=2).
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if b.Record(fail(), 5) {
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t.Error("should not transition after 1 fail from fully healthy")
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}
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if b.Record(fail(), 5) {
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t.Error("should not transition after 2 fails from fully healthy")
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}
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if b.State != StateUp {
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t.Errorf("state after 2 fails: got %s, want up", b.State)
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}
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// Third failure: counter 2→1 < rise=2 → Down.
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if !b.Record(fail(), 5) {
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t.Error("should transition to Down after fall=3 failures from fully healthy")
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}
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if b.State != StateDown {
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t.Errorf("state: got %s, want down", b.State)
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}
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}
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// TestUnknownToDownOnFirstFail: any failure while Unknown → Down immediately.
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func TestUnknownToDownOnFirstFail(t *testing.T) {
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b := newBackend()
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if !b.Record(fail(), 5) {
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t.Error("first fail from Unknown should transition to Down")
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}
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if b.State != StateDown {
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t.Errorf("state: got %s, want down", b.State)
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}
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}
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// TestHysteresis: alternating pass/fail keeps backend in degraded range without
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// bouncing between Up and Down. This is the key HAProxy counter property.
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func TestHysteresis(t *testing.T) {
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b := newBackend()
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// Drive to Up.
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b.Record(pass(), 5)
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b.Record(pass(), 5) // counter=2, state=Up
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// Alternate pass/fail. Counter oscillates 3↔2 (both in UP range for rise=2),
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// or 2↔1 (crossing the boundary). Let's trace:
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// Start: counter=2 (just became Up, was at 2=rise after second pass, then RecordPass incremented to 3... wait)
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// Actually: after first pass from Unknown (counter=0), counter=1. After second pass, counter=2=rise, RecordPass returns true → Up.
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// But RecordPass increments BEFORE checking: wasUp=false, counter becomes 2, IsUp()=true → returns true.
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// So after second pass: counter=2, state=Up.
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// max = rise+fall-1 = 2+3-1 = 4.
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// fail: counter=1 < rise=2 → RecordFail: wasDown=false (counter was 2=rise, IsUp=true),
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// counter becomes 1, IsUp()=false → returns true → Down!
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// Hmm, so one fail from counter=2 (barely Up) → Down? That's with rise=2.
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// The hysteresis is more visible with rise=2, fall=5: max=6.
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// Let's use a backend with more headroom.
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b2 := New("test", net.ParseIP("10.0.0.2"), 2, 5) // rise=2, fall=5, max=6
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// Drive to fully healthy.
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b2.Record(pass(), 5) // counter=1
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b2.Record(pass(), 5) // counter=2=rise → Up
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b2.Record(pass(), 5) // counter=3
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b2.Record(pass(), 5) // counter=4
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b2.Record(pass(), 5) // counter=5
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b2.Record(pass(), 5) // counter=6=max
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// Now alternate: fail drops from 6, pass brings back up.
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// Should not transition since counter stays in UP range (>=2).
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for i := 0; i < 4; i++ {
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transitioned := b2.Record(fail(), 5) // 6→5→4→3→2 (all >=rise=2)
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if transitioned {
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t.Errorf("fail %d: should not transition (counter in UP range)", i+1)
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}
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if !b2.Counter.IsUp() {
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t.Errorf("fail %d: should still be up", i+1)
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}
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if b2.Record(pass(), 5) { // re-increment
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t.Errorf("pass %d: should not transition (already Up)", i+1)
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}
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}
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if b2.State != StateUp {
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t.Errorf("after alternating: want up, got %s", b2.State)
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}
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}
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// TestNextInterval: correct interval selection based on counter state.
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func TestNextInterval(t *testing.T) {
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interval := 2 * time.Second
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fast := 500 * time.Millisecond
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down := 30 * time.Second
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b := New("test", net.ParseIP("10.0.0.1"), 2, 3) // max=4
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// Unknown (no probes yet): always use interval, never downInterval.
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if got := b.NextInterval(interval, fast, down); got != interval {
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t.Errorf("StateUnknown: got %v, want %v (interval)", got, interval)
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}
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// After first fail: counter=0, state=Down → downInterval.
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b.Record(ProbeResult{OK: false, Code: "L4CON"}, 5)
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if b.State != StateDown {
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t.Fatalf("expected StateDown after first fail, got %s", b.State)
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}
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if got := b.NextInterval(interval, fast, down); got != down {
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t.Errorf("StateDown/counter=0: got %v, want %v (down)", got, down)
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}
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// Drive to max (fully healthy) → interval.
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b.Counter.Health = b.Counter.Max()
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if got := b.NextInterval(interval, fast, down); got != interval {
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t.Errorf("counter=max: got %v, want %v (interval)", got, interval)
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}
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// Degraded (0 < counter < max) → fastInterval.
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b.Counter.Health = 1
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if got := b.NextInterval(interval, fast, down); got != fast {
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t.Errorf("counter=1 (degraded): got %v, want %v (fast)", got, fast)
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}
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// No fastInterval configured → falls back to interval.
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if got := b.NextInterval(interval, 0, down); got != interval {
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t.Errorf("degraded, no fast: got %v, want %v (interval)", got, interval)
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}
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// No downInterval configured → falls back to interval.
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b.Counter.Health = 0
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if got := b.NextInterval(interval, fast, 0); got != interval {
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t.Errorf("down, no downInterval: got %v, want %v (interval)", got, interval)
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}
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}
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func TestPauseResume(t *testing.T) {
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b := newBackend()
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b.State = StateUp
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changed := b.Pause(5)
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if !changed {
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t.Error("Pause should return true")
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}
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if b.State != StatePaused {
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t.Errorf("after Pause: got %s, want paused", b.State)
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}
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// Probes ignored while paused.
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if b.Record(pass(), 5) {
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t.Error("Record(pass) should not transition while paused")
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}
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if b.Record(fail(), 5) {
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t.Error("Record(fail) should not transition while paused")
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}
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if b.State != StatePaused {
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t.Errorf("state changed while paused: %s", b.State)
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}
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// Second Pause is a no-op.
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if b.Pause(5) {
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t.Error("second Pause should return false")
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}
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changed = b.Resume(5)
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if !changed {
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t.Error("Resume should return true")
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}
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if b.State != StateUnknown {
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t.Errorf("after Resume: got %s, want unknown", b.State)
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}
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// Resume on non-paused is a no-op.
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if b.Resume(5) {
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t.Error("Resume on non-paused should return false")
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}
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}
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func TestTransitionHistory(t *testing.T) {
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b := newBackend()
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maxHistory := 3
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// Drive several state changes. Each cycle: pass×2→Up, fail→Down (Unknown→Down on first fail).
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b.Record(fail(), maxHistory) // Unknown→Down
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b.Record(pass(), maxHistory) // counter++
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b.Record(pass(), maxHistory) // Down→Up
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b.Record(fail(), maxHistory) // Up: counter drops
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b.Record(fail(), maxHistory) // Up: counter drops
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b.Record(fail(), maxHistory) // Up→Down
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b.Record(pass(), maxHistory) // counter++
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b.Record(pass(), maxHistory) // Down→Up
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if len(b.Transitions) != maxHistory {
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t.Errorf("transitions capped at %d, got %d", maxHistory, len(b.Transitions))
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}
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// Newest first: last transition was →Up.
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if b.Transitions[0].To != StateUp {
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t.Errorf("newest transition: got %s, want up", b.Transitions[0].To)
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}
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// Transitions carry ProbeResult.
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if b.Transitions[0].Result.Code == "" {
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t.Error("transition result code should not be empty")
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}
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}
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func TestTransitionTimestamp(t *testing.T) {
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b := newBackend()
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before := time.Now()
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b.Record(fail(), 5)
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after := time.Now()
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if len(b.Transitions) == 0 {
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t.Fatal("expected a transition")
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}
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ts := b.Transitions[0].At
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if ts.Before(before) || ts.After(after) {
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t.Errorf("transition timestamp %v outside [%v, %v]", ts, before, after)
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}
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}
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func TestStateString(t *testing.T) {
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cases := []struct {
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s State
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want string
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}{
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{StateUnknown, "unknown"},
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{StateUp, "up"},
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{StateDown, "down"},
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{StatePaused, "paused"},
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}
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for _, c := range cases {
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if c.s.String() != c.want {
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t.Errorf("State(%d).String() = %q, want %q", c.s, c.s.String(), c.want)
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}
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}
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}
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