Remove dependency on external cache package

Makefile

@@ -6,7 +6,7 @@ docker-dev:
 
 docker-test:
 	docker compose -f docker-compose.yml -f docker-compose.dev.yml run --rm -p 2416:2416 challenge-bypass bash -c \
-	"(aws dynamodb delete-table \
+	"export AWS_PAGER='' && (aws dynamodb delete-table \
 	--table-name redemptions --endpoint-url http://dynamodb:8000 --region us-west-2  || \
 	aws dynamodb create-table \
 	--attribute-definitions AttributeName=id,AttributeType=S \

go.mod

@@ -17,7 +17,6 @@ require (
 	github.com/google/uuid v1.6.0
 	github.com/jmoiron/sqlx v1.3.5
 	github.com/lib/pq v1.10.9
-	github.com/patrickmn/go-cache v2.1.0+incompatible
 	github.com/prometheus/client_golang v1.14.0
 	github.com/robfig/cron/v3 v3.0.1
 	github.com/satori/go.uuid v1.2.0

go.sum

@@ -206,8 +206,6 @@ github.com/opencontainers/go-digest v1.0.0 h1:apOUWs51W5PlhuyGyz9FCeeBIOUDA/6nW8
 github.com/opencontainers/go-digest v1.0.0/go.mod h1:0JzlMkj0TRzQZfJkVvzbP0HBR3IKzErnv2BNG4W4MAM=
 github.com/opencontainers/image-spec v1.1.0 h1:8SG7/vwALn54lVB/0yZ/MMwhFrPYtpEHQb2IpWsCzug=
 github.com/opencontainers/image-spec v1.1.0/go.mod h1:W4s4sFTMaBeK1BQLXbG4AdM2szdn85PY75RI83NrTrM=
-github.com/patrickmn/go-cache v2.1.0+incompatible h1:HRMgzkcYKYpi3C8ajMPV8OFXaaRUnok+kx1WdO15EQc=
-github.com/patrickmn/go-cache v2.1.0+incompatible/go.mod h1:3Qf8kWWT7OJRJbdiICTKqZju1ZixQ/KpMGzzAfe6+WQ=
 github.com/pierrec/lz4/v4 v4.1.15/go.mod h1:gZWDp/Ze/IJXGXf23ltt2EXimqmTUXEy0GFuRQyBid4=
 github.com/pierrec/lz4/v4 v4.1.17 h1:kV4Ip+/hUBC+8T6+2EgburRtkE9ef4nbY3f4dFhGjMc=
 github.com/pierrec/lz4/v4 v4.1.17/go.mod h1:gZWDp/Ze/IJXGXf23ltt2EXimqmTUXEy0GFuRQyBid4=

server/cache.go

@@ -0,0 +1,140 @@
+package server
+
+import (
+	"sync"
+	"time"
+)
+
+// CachingConfig is how long data is cached
+type CachingConfig struct {
+	Enabled       bool `json:"enabled"`
+	ExpirationSec int  `json:"expirationSec"`
+}
+
+// CacheInterface cache functions
+type CacheInterface interface {
+	Get(k string) (interface{}, bool)
+	Delete(k string)
+	SetDefault(k string, x interface{})
+}
+
+// SimpleCache implements CacheInterface using standard library
+type SimpleCache struct {
+	items             sync.Map
+	defaultExpiration time.Duration
+	cleanupInterval   time.Duration
+	stopCleanup       chan bool
+}
+
+type cacheItem struct {
+	value      interface{}
+	expiration int64 // Unix timestamp for expiration
+}
+
+// NewSimpleCache creates a new cache with the given default expiration and cleanup interval
+func NewSimpleCache(defaultExpiration, cleanupInterval time.Duration) *SimpleCache {
+	cache := &SimpleCache{
+		defaultExpiration: defaultExpiration,
+		cleanupInterval:   cleanupInterval,
+		stopCleanup:       make(chan bool),
+	}
+
+	// Start cleanup routine if cleanup interval > 0
+	if cleanupInterval > 0 {
+		go cache.startCleanupTimer()
+	}
+
+	return cache
+}
+
+// startCleanupTimer starts a timer that periodically cleans up expired items
+func (c *SimpleCache) startCleanupTimer() {
+	ticker := time.NewTicker(c.cleanupInterval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ticker.C:
+			c.deleteExpired()
+		case <-c.stopCleanup:
+			return
+		}
+	}
+}
+
+// deleteExpired deletes expired items from the cache
+func (c *SimpleCache) deleteExpired() {
+	now := time.Now().UnixNano()
+	c.items.Range(func(key, value interface{}) bool {
+		item, ok := value.(cacheItem)
+		if ok && item.expiration > 0 && item.expiration < now {
+			c.items.Delete(key)
+		}
+		return true
+	})
+}
+
+// Get retrieves an item from the cache
+func (c *SimpleCache) Get(k string) (interface{}, bool) {
+	value, found := c.items.Load(k)
+	if !found {
+		return nil, false
+	}
+
+	item, ok := value.(cacheItem)
+	if !ok {
+		return nil, false
+	}
+
+	// Check if item has expired
+	if item.expiration > 0 && item.expiration < time.Now().UnixNano() {
+		c.items.Delete(k)
+		return nil, false
+	}
+
+	return item.value, true
+}
+
+// Delete removes an item from the cache
+func (c *SimpleCache) Delete(k string) {
+	c.items.Delete(k)
+}
+
+// SetDefault adds an item to the cache with the default expiration time
+func (c *SimpleCache) SetDefault(k string, x interface{}) {
+	var expiration int64 = 0
+	if c.defaultExpiration > 0 {
+		expiration = time.Now().Add(c.defaultExpiration).UnixNano()
+	}
+
+	c.items.Store(k, cacheItem{
+		value:      x,
+		expiration: expiration,
+	})
+}
+
+func retrieveFromCache(
+	caches map[string]CacheInterface,
+	cacheName string,
+	key string,
+) interface{} {
+	if caches != nil {
+		if cached, found := caches[cacheName].Get(key); found {
+			return cached
+		}
+	}
+	return nil
+}
+
+func bootstrapCache(cfg DBConfig) map[string]CacheInterface {
+	caches := make(map[string]CacheInterface)
+	defaultDuration := time.Duration(cfg.CachingConfig.ExpirationSec) * time.Second
+	cleanupInterval := defaultDuration * 2
+
+	caches["issuers"] = NewSimpleCache(defaultDuration, cleanupInterval)
+	caches["issuer"] = NewSimpleCache(defaultDuration, cleanupInterval)
+	caches["redemptions"] = NewSimpleCache(defaultDuration, cleanupInterval)
+	caches["issuercohort"] = NewSimpleCache(defaultDuration, cleanupInterval)
+
+	return caches
+}

server/db.go

@@ -22,16 +22,9 @@ import (
 	_ "github.com/golang-migrate/migrate/v4/source/file" // Why?
 	"github.com/jmoiron/sqlx"
 	"github.com/lib/pq"
-	cache "github.com/patrickmn/go-cache"
 	"github.com/prometheus/client_golang/prometheus"
 )
 
-// CachingConfig is how long data is cached
-type CachingConfig struct {
-	Enabled       bool `json:"enabled"`
-	ExpirationSec int  `json:"expirationSec"`
-}
-
 // DBConfig defines app configurations
 type DBConfig struct {
 	ConnectionURI           string        `json:"connectionURI"`
@@ -61,13 +54,6 @@ type RedemptionV2 struct {
 	Offset    int64     `json:"offset"`
 }
 
-// CacheInterface cache functions
-type CacheInterface interface {
-	Get(k string) (interface{}, bool)
-	Delete(k string)
-	SetDefault(k string, x interface{})
-}
-
 var (
 	errIssuerNotFound       = errors.New("issuer with the given name does not exist")
 	errIssuerCohortNotFound = errors.New("issuer with the given name and cohort does not exist")
@@ -843,26 +829,3 @@ func isPostgresNotFoundError(err error) bool {
 	}
 	return false
 }
-
-func retrieveFromCache(
-	caches map[string]CacheInterface,
-	cacheName string,
-	key string,
-) interface{} {
-	if caches != nil {
-		if cached, found := caches[cacheName].Get(key); found {
-			return cached
-		}
-	}
-	return nil
-}
-
-func bootstrapCache(cfg DBConfig) map[string]CacheInterface {
-	caches := make(map[string]CacheInterface)
-	defaultDuration := time.Duration(cfg.CachingConfig.ExpirationSec) * time.Second
-	caches["issuers"] = cache.New(defaultDuration, 2*defaultDuration)
-	caches["issuer"] = cache.New(defaultDuration, 2*defaultDuration)
-	caches["redemptions"] = cache.New(defaultDuration, 2*defaultDuration)
-	caches["issuercohort"] = cache.New(defaultDuration, 2*defaultDuration)
-	return caches
-}