gatus/watchdog/watchdog.go
2020-10-30 21:01:12 +05:30

86 lines
2.6 KiB
Go

package watchdog
import (
"encoding/json"
"fmt"
"log"
"sync"
"time"
"github.com/TwinProduction/gatus/config"
"github.com/TwinProduction/gatus/core"
"github.com/TwinProduction/gatus/metric"
)
var (
serviceResults = make(map[string][]*core.Result)
// serviceResultsMutex is used to prevent concurrent map access
serviceResultsMutex sync.RWMutex
// monitoringMutex is used to prevent multiple services from being evaluated at the same time.
// Without this, conditions using response time may become inaccurate.
monitoringMutex sync.Mutex
)
// GetJSONEncodedServiceResults returns a list of the last 20 results for each services encoded using json.Marshal.
// The reason why the encoding is done here is because we use a mutex to prevent concurrent map access.
func GetJSONEncodedServiceResults() ([]byte, error) {
serviceResultsMutex.RLock()
data, err := json.Marshal(serviceResults)
serviceResultsMutex.RUnlock()
return data, err
}
// Monitor loops over each services and starts a goroutine to monitor each services separately
func Monitor(cfg *config.Config) {
for _, service := range cfg.Services {
go monitor(service)
// To prevent multiple requests from running at the same time
time.Sleep(1111 * time.Millisecond)
}
}
// monitor monitors a single service in a loop
func monitor(service *core.Service) {
cfg := config.Get()
for {
if !cfg.DisableMonitoringLock {
// By placing the lock here, we prevent multiple services from being monitored at the exact same time, which
// could cause performance issues and return inaccurate results
monitoringMutex.Lock()
}
if cfg.Debug {
log.Printf("[watchdog][monitor] Monitoring serviceName=%s", service.Name)
}
result := service.EvaluateHealth()
metric.PublishMetricsForService(service, result)
serviceResultsMutex.Lock()
serviceResults[service.Name] = append(serviceResults[service.Name], result)
if len(serviceResults[service.Name]) > 20 {
serviceResults[service.Name] = serviceResults[service.Name][1:]
}
serviceResultsMutex.Unlock()
var extra string
if !result.Success {
extra = fmt.Sprintf("responseBody=%s", result.Body)
}
log.Printf(
"[watchdog][monitor] Monitored serviceName=%s; success=%v; errors=%d; requestDuration=%s; %s",
service.Name,
result.Success,
len(result.Errors),
result.Duration.Round(time.Millisecond),
extra,
)
HandleAlerting(service, result)
if cfg.Debug {
log.Printf("[watchdog][monitor] Waiting for interval=%s before monitoring serviceName=%s again", service.Interval, service.Name)
}
if !cfg.DisableMonitoringLock {
monitoringMutex.Unlock()
}
time.Sleep(service.Interval)
}
}