use docker healthcheck result if possible

internal/watcher/health/monitor/docker.go

@@ -0,0 +1,51 @@
+package monitor
+
+import (
+	"bytes"
+
+	"github.com/yusing/go-proxy/internal/docker"
+	"github.com/yusing/go-proxy/internal/net/types"
+
+	dockerTypes "github.com/docker/docker/api/types"
+	"github.com/yusing/go-proxy/internal/watcher/health"
+)
+
+type DockerHealthMonitor struct {
+	*monitor
+	client      *docker.SharedClient
+	containerID string
+	fallback    health.HealthChecker
+}
+
+func NewDockerHealthMonitor(client *docker.SharedClient, containerID string, config *health.HealthCheckConfig, fallback health.HealthChecker) *DockerHealthMonitor {
+	mon := new(DockerHealthMonitor)
+	mon.client = client
+	mon.containerID = containerID
+	mon.monitor = newMonitor(types.URL{}, config, mon.CheckHealth)
+	mon.fallback = fallback
+	return mon
+}
+
+func (mon *DockerHealthMonitor) CheckHealth() (result *health.HealthCheckResult, err error) {
+	cont, err := mon.client.ContainerInspect(mon.task.Context(), mon.containerID)
+	if err != nil {
+		return mon.fallback.CheckHealth()
+	}
+	if cont.State.Health == nil {
+		return mon.fallback.CheckHealth()
+	}
+	result = new(health.HealthCheckResult)
+	result.Healthy = cont.State.Health.Status == dockerTypes.Healthy
+	detail := new(bytes.Buffer)
+	for _, status := range cont.State.Health.Log {
+		detail.WriteString(status.Output)
+		detail.WriteString("\n")
+	}
+	result.Detail = detail.String()
+	if len(cont.State.Health.Log) > 0 {
+		last := cont.State.Health.Log[len(cont.State.Health.Log)-1].End
+		first := cont.State.Health.Log[0].Start
+		result.Latency = last.Sub(first)
+	}
+	return
+}