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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,20 @@ | ||
| package db | ||
|
|
||
| import ( | ||
| "context" | ||
| "database/sql" | ||
| ) | ||
|
|
||
| type Probe struct { | ||
| db *sql.DB | ||
| } | ||
|
|
||
| func NewProbe(db *sql.DB) Probe { | ||
| return Probe{ | ||
| db: db, | ||
| } | ||
| } | ||
|
|
||
| func (p Probe) Check(ctx context.Context) error { | ||
| return p.db.PingContext(ctx) | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,24 @@ | ||
| package discord | ||
|
|
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| import ( | ||
| "context" | ||
|
|
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| "github.com/bwmarrin/discordgo" | ||
| ) | ||
|
|
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| type Probe struct { | ||
| discord *discordgo.Session | ||
| } | ||
|
|
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| func NewProbe( | ||
| discord *discordgo.Session, | ||
| ) Probe { | ||
| return Probe{ | ||
| discord: discord, | ||
| } | ||
| } | ||
|
|
||
| func (p Probe) Check(_ context.Context) error { | ||
| _, err := p.discord.User("@me") | ||
| return err | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,151 @@ | ||
| package healthcheck | ||
|
|
||
| import ( | ||
| "context" | ||
| "log" | ||
| "log/slog" | ||
| "sync" | ||
| "time" | ||
|
|
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| "github.com/valyala/fasthttp" | ||
| ) | ||
|
|
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| type Healthcheck struct { | ||
| log *slog.Logger | ||
| probes map[string]Probe | ||
| timeoutDegraded time.Duration | ||
| timeoutUnhealthy time.Duration | ||
| } | ||
|
|
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| func New( | ||
| log *slog.Logger, | ||
| opts ...Option, | ||
| ) *Healthcheck { | ||
| hc := &Healthcheck{ | ||
| log: log, | ||
| probes: map[string]Probe{}, | ||
| timeoutDegraded: 1 * time.Second, | ||
| timeoutUnhealthy: 10 * time.Second, | ||
| } | ||
|
|
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| for _, opt := range opts { | ||
| opt(hc) | ||
| } | ||
|
|
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| return hc | ||
| } | ||
|
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| func (hc *Healthcheck) Serve(address string) *fasthttp.Server { | ||
| s := &fasthttp.Server{ | ||
| Handler: func(ctx *fasthttp.RequestCtx) { | ||
| if string(ctx.Path()) != "/health" || !ctx.IsGet() { | ||
| ctx.NotFound() | ||
| return | ||
| } | ||
|
|
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| status := hc.handle(ctx) | ||
|
|
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| if status == StatusHealthy { | ||
| ctx.SetStatusCode(fasthttp.StatusOK) | ||
| } else { | ||
| ctx.SetStatusCode(fasthttp.StatusServiceUnavailable) | ||
| } | ||
| ctx.SetBodyString(status.String()) | ||
| }, | ||
| } | ||
|
|
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| go func() { | ||
| err := s.ListenAndServe(address) | ||
| if err != nil { | ||
| log.Fatalln("healthcheck server error", "error", err) | ||
| } | ||
| }() | ||
|
|
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| return s | ||
| } | ||
|
|
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| func (hc *Healthcheck) handle(ctx context.Context) Status { | ||
| nProbes := len(hc.probes) | ||
|
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| wg := &sync.WaitGroup{} | ||
| wg.Add(nProbes) | ||
|
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| statuses := make(chan Status, nProbes) | ||
|
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| for name, probe := range hc.probes { | ||
| hc.probeCheck( | ||
| hc.log.With("probe", name), ctx, wg, probe, statuses, | ||
| ) | ||
| } | ||
|
|
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| wg.Wait() | ||
| close(statuses) | ||
|
|
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| status := StatusHealthy | ||
| for s := range statuses { | ||
| if s <= status { | ||
| continue | ||
| } | ||
|
|
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| status = s | ||
| if status == StatusUnhealthy { | ||
| break | ||
| } | ||
| } | ||
|
|
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| return status | ||
| } | ||
|
|
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| func (hc *Healthcheck) probeCheck( | ||
| log *slog.Logger, | ||
| ctx context.Context, | ||
| wg *sync.WaitGroup, | ||
| probe Probe, | ||
| status chan Status, | ||
| ) { | ||
| timedCtx, cancel := context.WithTimeout(ctx, hc.timeoutUnhealthy) | ||
|
|
||
| defer func() { | ||
| if err := recover(); err != nil { | ||
| log.ErrorContext( | ||
| ctx, | ||
| "probe panicked", | ||
| "panic", err, | ||
| ) | ||
|
|
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| status <- StatusUnhealthy | ||
| } | ||
|
|
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| cancel() | ||
| wg.Done() | ||
| }() | ||
|
|
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| probeTime := time.Now() | ||
| err := probe.Check(timedCtx) | ||
| probeDuration := time.Since(probeTime) | ||
|
|
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| if err != nil || probeDuration > hc.timeoutUnhealthy { | ||
| log.ErrorContext( | ||
| ctx, | ||
| "failed to probe", | ||
| "error", err, | ||
| "duration", probeDuration.String(), | ||
| ) | ||
|
|
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| status <- StatusUnhealthy | ||
| return | ||
| } | ||
|
|
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| if probeDuration > hc.timeoutDegraded { | ||
| log.WarnContext( | ||
| ctx, | ||
| "probe is degraded", | ||
| "duration", probeDuration.String(), | ||
| ) | ||
|
|
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| status <- StatusDegraded | ||
| return | ||
| } | ||
|
|
||
| status <- StatusHealthy | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,39 @@ | ||
| package healthcheck | ||
|
|
||
| import ( | ||
| "fmt" | ||
| "time" | ||
| ) | ||
|
|
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| type Option func(hc *Healthcheck) | ||
|
|
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| func WithProbe(name string, probe Probe) Option { | ||
| return func(hc *Healthcheck) { | ||
| if _, ok := hc.probes[name]; ok { | ||
| p := fmt.Sprintf("healthcheck probe '%s' already registered", name) | ||
| panic(p) | ||
| } | ||
|
|
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| hc.probes[name] = probe | ||
| } | ||
| } | ||
|
|
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| func WithTimeoutDegraded(timeout time.Duration) Option { | ||
| return func(hc *Healthcheck) { | ||
| if timeout <= 0 { | ||
| panic("healthcheck timeout must be greater than zero") | ||
| } | ||
|
|
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| hc.timeoutDegraded = timeout | ||
| } | ||
| } | ||
|
|
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| func WithTimeoutUnhealthy(timeout time.Duration) Option { | ||
| return func(hc *Healthcheck) { | ||
| if timeout <= 0 { | ||
| panic("healthcheck timeout must be greater than zero") | ||
| } | ||
|
|
||
| hc.timeoutUnhealthy = timeout | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,9 @@ | ||
| package healthcheck | ||
|
|
||
| import ( | ||
| "context" | ||
| ) | ||
|
|
||
| type Probe interface { | ||
| Check(ctx context.Context) error | ||
| } |
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