feat: initial commit — uptime monitor (forked from go-upkeep)

Go-based uptime monitor with SQLite/Postgres storage, TUI dashboard,
SSH server, alerting, and clustering support.
This commit is contained in:
2026-05-14 11:05:10 -04:00
commit 02f0a39d97
25 changed files with 2834 additions and 0 deletions
+70
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package monitor
import (
"sync"
"time"
)
const maxHistoryLen = 30
type SiteHistory struct {
Latencies []time.Duration
Statuses []bool
TotalChecks int
UpChecks int
}
var (
histories = make(map[int]*SiteHistory)
historyMu sync.RWMutex
)
func RecordCheck(siteID int, latency time.Duration, isUp bool) {
historyMu.Lock()
defer historyMu.Unlock()
h, ok := histories[siteID]
if !ok {
h = &SiteHistory{}
histories[siteID] = h
}
h.TotalChecks++
if isUp {
h.UpChecks++
}
h.Latencies = append(h.Latencies, latency)
if len(h.Latencies) > maxHistoryLen {
h.Latencies = h.Latencies[len(h.Latencies)-maxHistoryLen:]
}
h.Statuses = append(h.Statuses, isUp)
if len(h.Statuses) > maxHistoryLen {
h.Statuses = h.Statuses[len(h.Statuses)-maxHistoryLen:]
}
}
func GetHistory(siteID int) (SiteHistory, bool) {
historyMu.RLock()
defer historyMu.RUnlock()
h, ok := histories[siteID]
if !ok {
return SiteHistory{}, false
}
cp := SiteHistory{
TotalChecks: h.TotalChecks,
UpChecks: h.UpChecks,
Latencies: make([]time.Duration, len(h.Latencies)),
Statuses: make([]bool, len(h.Statuses)),
}
copy(cp.Latencies, h.Latencies)
copy(cp.Statuses, h.Statuses)
return cp, true
}
func RemoveHistory(siteID int) {
historyMu.Lock()
defer historyMu.Unlock()
delete(histories, siteID)
}
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package monitor
import (
"crypto/tls"
"fmt"
"go-upkeep/internal/alert"
"go-upkeep/internal/models"
"go-upkeep/internal/store"
"net/http"
"sync"
"time"
)
// --- LOGGING ---
var (
LogStore []string
LogMutex sync.RWMutex
)
func AddLog(msg string) {
LogMutex.Lock()
defer LogMutex.Unlock()
ts := time.Now().Format("15:04:05")
entry := fmt.Sprintf("[%s] %s", ts, msg)
LogStore = append([]string{entry}, LogStore...)
if len(LogStore) > 100 {
LogStore = LogStore[:100]
}
}
func GetLogs() []string {
LogMutex.RLock()
defer LogMutex.RUnlock()
logs := make([]string, len(LogStore))
copy(logs, LogStore)
return logs
}
// --- ENGINE ---
var (
LiveState = make(map[int]models.Site)
Mutex sync.RWMutex
// Global Switch for HA
isActive = true
activeMutex sync.RWMutex
)
func SetEngineActive(active bool) {
activeMutex.Lock()
defer activeMutex.Unlock()
if isActive != active {
isActive = active
status := "RESUMED (Active)"
if !active {
status = "PAUSED (Passive)"
}
AddLog(fmt.Sprintf("Engine %s", status))
}
}
func IsEngineActive() bool {
activeMutex.RLock()
defer activeMutex.RUnlock()
return isActive
}
func RecordHeartbeat(token string) bool {
if !IsEngineActive() {
return false
} // Only Leader accepts Push
Mutex.Lock()
defer Mutex.Unlock()
var targetID int = -1
for id, s := range LiveState {
if s.Type == "push" && s.Token == token {
targetID = id
break
}
}
if targetID == -1 {
return false
}
site := LiveState[targetID]
site.LastCheck = time.Now()
wasDown := site.Status == "DOWN"
site.Status = "UP"
site.FailureCount = 0
site.Latency = 0
LiveState[targetID] = site
if wasDown {
AddLog(fmt.Sprintf("Push Monitor '%s' recovered", site.Name))
triggerAlert(site.AlertID, "✅ RECOVERY", fmt.Sprintf("Push Monitor '%s' is receiving heartbeats.", site.Name))
}
return true
}
func StartEngine() {
go func() {
for {
s_instance := store.Get()
if s_instance == nil {
time.Sleep(1 * time.Second)
continue
}
sites := s_instance.GetSites()
for _, s := range sites {
Mutex.RLock()
_, exists := LiveState[s.ID]
Mutex.RUnlock()
if !exists {
Mutex.Lock()
s.Status = "PENDING"
if s.Type == "push" {
s.LastCheck = time.Now()
}
LiveState[s.ID] = s
Mutex.Unlock()
go monitorRoutine(s.ID)
}
}
time.Sleep(5 * time.Second)
}
}()
}
func UpdateSiteConfig(id int, name, url, sType string, interval, alertID int, checkSSL bool, threshold, retries int) {
Mutex.Lock()
defer Mutex.Unlock()
if s, ok := LiveState[id]; ok {
s.Name = name
s.URL = url
s.Type = sType
s.Interval = interval
s.AlertID = alertID
s.CheckSSL = checkSSL
s.ExpiryThreshold = threshold
s.MaxRetries = retries
LiveState[id] = s
}
}
func RemoveSite(id int) {
Mutex.Lock()
delete(LiveState, id)
Mutex.Unlock()
RemoveHistory(id)
}
func monitorRoutine(id int) {
checkByID(id)
for {
// If paused, just sleep loop to keep goroutine alive but idle
if !IsEngineActive() {
time.Sleep(5 * time.Second)
continue
}
Mutex.RLock()
site, exists := LiveState[id]
Mutex.RUnlock()
if !exists {
return
}
interval := site.Interval
if interval < 5 {
interval = 5
}
time.Sleep(time.Duration(interval) * time.Second)
checkByID(id)
}
}
func checkByID(id int) {
if !IsEngineActive() {
return
}
Mutex.RLock()
site, exists := LiveState[id]
Mutex.RUnlock()
if !exists {
return
}
if site.Type == "http" {
checkHTTP(site)
} else {
checkPush(site)
}
}
func checkPush(site models.Site) {
deadline := site.LastCheck.Add(time.Duration(site.Interval) * time.Second).Add(5 * time.Second)
if time.Now().After(deadline) {
handleStatusChange(site, "DOWN", 0, 0)
} else {
if site.Status != "UP" {
handleStatusChange(site, "UP", 200, 0)
}
}
}
func checkHTTP(site models.Site) {
start := time.Now()
client := &http.Client{Timeout: 5 * time.Second, Transport: &http.Transport{TLSClientConfig: &tls.Config{InsecureSkipVerify: true}}}
resp, err := client.Get(site.URL)
latency := time.Since(start)
rawStatus := "UP"
rawCode := 0
var certExpiry time.Time
hasSSL := false
if err != nil {
rawStatus = "DOWN"
} else {
defer resp.Body.Close()
rawCode = resp.StatusCode
if resp.StatusCode >= 400 {
rawStatus = "DOWN"
}
if site.CheckSSL && resp.TLS != nil && len(resp.TLS.PeerCertificates) > 0 {
hasSSL = true
cert := resp.TLS.PeerCertificates[0]
certExpiry = cert.NotAfter
if time.Now().After(cert.NotAfter) {
rawStatus = "SSL EXP"
}
}
}
updatedSite := site
updatedSite.HasSSL = hasSSL
updatedSite.CertExpiry = certExpiry
updatedSite.Latency = latency
updatedSite.LastCheck = time.Now()
handleStatusChange(updatedSite, rawStatus, rawCode, latency)
}
func handleStatusChange(site models.Site, rawStatus string, code int, latency time.Duration) {
// Double check we are still leader before alerting
if !IsEngineActive() {
return
}
newState := site
newState.StatusCode = code
if site.Status == "UP" && rawStatus != "UP" {
newState.FailureCount++
if newState.FailureCount > site.MaxRetries {
newState.Status = rawStatus
newState.FailureCount = site.MaxRetries + 1
AddLog(fmt.Sprintf("Monitor '%s' confirmed DOWN", site.Name))
} else {
AddLog(fmt.Sprintf("Monitor '%s' failed check %d/%d", site.Name, newState.FailureCount, site.MaxRetries))
}
} else if rawStatus == "UP" {
newState.FailureCount = 0
newState.Status = "UP"
} else {
newState.Status = rawStatus
newState.FailureCount = site.MaxRetries + 1
}
if site.Type == "http" && site.CheckSSL && site.HasSSL {
daysLeft := int(time.Until(site.CertExpiry).Hours() / 24)
if daysLeft <= site.ExpiryThreshold && !site.SentSSLWarning && rawStatus != "SSL EXP" {
triggerAlert(site.AlertID, "SSL WARNING", fmt.Sprintf("SSL for '%s' expires in %d days", site.Name, daysLeft))
newState.SentSSLWarning = true
} else if daysLeft > site.ExpiryThreshold {
newState.SentSSLWarning = false
}
}
Mutex.Lock()
if _, ok := LiveState[site.ID]; ok {
LiveState[site.ID] = newState
}
Mutex.Unlock()
RecordCheck(site.ID, latency, rawStatus == "UP")
isBroken := func(s string) bool { return s == "DOWN" || s == "SSL EXP" }
if !isBroken(site.Status) && isBroken(newState.Status) && newState.Status != "PENDING" {
msg := fmt.Sprintf("Monitor '%s' is DOWN (%s)", site.Name, rawStatus)
if site.Type == "push" {
msg = fmt.Sprintf("Push Monitor '%s' missed heartbeat.", site.Name)
}
triggerAlert(site.AlertID, "🚨 ALERT", msg)
}
if isBroken(site.Status) && newState.Status == "UP" {
triggerAlert(site.AlertID, "✅ RECOVERY", fmt.Sprintf("Monitor '%s' is UP", site.Name))
}
}
func triggerAlert(alertID int, title, message string) {
s_instance := store.Get()
if s_instance == nil {
return
}
cfg, ok := s_instance.GetAlert(alertID)
if !ok {
return
}
provider := alert.GetProvider(cfg)
if provider != nil {
go func() { provider.Send(title, message) }()
}
}