cache: Move to own interface package

With this interface it will be easy to support multiple cache types.

cache.go

@@ -1,63 +0,0 @@
-package main
-
-import (
-	"sync"
-	"time"
-)
-
-type fingerprint string
-type status string
-
-type cachedAlert struct {
-	expires time.Time
-	status  status
-}
-
-type cache struct {
-	mu       sync.Mutex
-	duration time.Duration
-	alerts   map[fingerprint]*cachedAlert
-}
-
-func (a *cachedAlert) expired() bool {
-	return a.expires.Before(time.Now())
-}
-
-func newCache(d time.Duration) *cache {
-	c := new(cache)
-	c.duration = d
-	c.alerts = make(map[fingerprint]*cachedAlert)
-
-	return c
-}
-
-func (c *cache) cleanup() {
-	c.mu.Lock()
-	defer c.mu.Unlock()
-	for key, value := range c.alerts {
-		if value.expired() {
-			delete(c.alerts, key)
-		}
-	}
-}
-
-func (c *cache) set(f fingerprint, s status) {
-	c.mu.Lock()
-	defer c.mu.Unlock()
-	alert := new(cachedAlert)
-	alert.expires = time.Now().Add(c.duration)
-	alert.status = s
-
-	c.alerts[f] = alert
-}
-
-func (c *cache) contains(f fingerprint, s status) bool {
-	c.mu.Lock()
-	defer c.mu.Unlock()
-	alert, ok := c.alerts[f]
-	if ok {
-		return alert.status == s
-	}
-
-	return false
-}

cache/cache.go

@@ -0,0 +1,9 @@
+// Package cache includes a memory cache for ntfy-alertmanager.
+package cache
+
+// Cache is the interface that describes a cache for ntfy-alertmanager.
+type Cache interface {
+	Set(fingerprint string, status string)
+	Contains(fingerprint string, status string) bool
+	Cleanup()
+}

cache/memory.go

@@ -0,0 +1,67 @@
+package cache
+
+import (
+	"sync"
+	"time"
+)
+
+// MemoryCache is the in-memory cache.
+type MemoryCache struct {
+	mu       sync.Mutex
+	duration time.Duration
+	alerts   map[string]*cachedAlert
+}
+
+type cachedAlert struct {
+	expires time.Time
+	status  string
+}
+
+// NewMemoryCache creates a in-memory cache.
+func NewMemoryCache(d time.Duration) Cache {
+	c := new(MemoryCache)
+	c.duration = d
+	c.alerts = make(map[string]*cachedAlert)
+
+	return c
+}
+
+// Set saves an alert in the cache.
+func (c *MemoryCache) Set(fingerprint string, status string) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	alert := new(cachedAlert)
+	alert.expires = time.Now().Add(c.duration)
+	alert.status = status
+
+	c.alerts[fingerprint] = alert
+}
+
+// Contains checks if an alert with a given fingerprint is in the cache
+// and checks if the status matches.
+func (c *MemoryCache) Contains(fingerprint string, status string) bool {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	alert, ok := c.alerts[fingerprint]
+	if ok {
+		return alert.status == status
+	}
+
+	return false
+}
+
+func (a *cachedAlert) expired() bool {
+	return a.expires.Before(time.Now())
+}
+
+// Cleanup iterates over all alerts in the cache and removes them, if they
+// are expired.
+func (c *MemoryCache) Cleanup() {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	for key, value := range c.alerts {
+		if value.expired() {
+			delete(c.alerts, key)
+		}
+	}
+}

main.go

@@ -15,6 +15,7 @@ import (
 	"time"
 
 	"git.xenrox.net/~xenrox/go-log"
+	"git.xenrox.net/~xenrox/ntfy-alertmanager/cache"
 	"golang.org/x/text/cases"
 	"golang.org/x/text/language"
 )
@@ -24,7 +25,7 @@ var version = "dev"
 type bridge struct {
 	cfg    *config
 	logger *log.Logger
-	cache  *cache
+	cache  cache.Cache
 	client *httpClient
 }
 
@@ -41,7 +42,7 @@ type alert struct {
 	Status      string            `json:"status"`
 	Labels      map[string]string `json:"labels"`
 	Annotations map[string]string `json:"annotations"`
-	Fingerprint fingerprint       `json:"fingerprint"`
+	Fingerprint string            `json:"fingerprint"`
 }
 
 type notification struct {
@@ -51,14 +52,14 @@ type notification struct {
 	tags        string
 	icon        string
 	silenceBody string
-	fingerprint fingerprint
+	fingerprint string
 	status      string
 }
 
 func (br *bridge) singleAlertNotifications(p *payload) []*notification {
 	var notifications []*notification
 	for _, alert := range p.Alerts {
-		if br.cache.contains(alert.Fingerprint, status(alert.Status)) {
+		if br.cache.Contains(alert.Fingerprint, alert.Status) {
 			br.logger.Debugf("Alert %s skipped: Still in cache", alert.Fingerprint)
 			continue
 		}
@@ -323,7 +324,7 @@ func (br *bridge) handleWebhooks(w http.ResponseWriter, r *http.Request) {
 			if err != nil {
 				br.logger.Errorf("Failed to publish notification: %v", err)
 			} else {
-				br.cache.set(n.fingerprint, status(n.status))
+				br.cache.Set(n.fingerprint, n.status)
 			}
 		}
 	} else {
@@ -365,7 +366,7 @@ func (br *bridge) runCleanup() {
 	for {
 		time.Sleep(br.cfg.cache.CleanupInterval)
 		br.logger.Info("Pruning cache")
-		br.cache.cleanup()
+		br.cache.Cleanup()
 	}
 }
 
@@ -394,7 +395,8 @@ func main() {
 
 	client := &httpClient{&http.Client{Timeout: time.Second * 3}}
 
-	bridge := &bridge{cfg: cfg, logger: logger, cache: newCache(cfg.cache.Duration), client: client}
+	c := cache.NewMemoryCache(cfg.cache.Duration)
+	bridge := &bridge{cfg: cfg, logger: logger, cache: c, client: client}
 
 	logger.Infof("Listening on %s, ntfy-alertmanager %s", cfg.HTTPAddress, version)