feat: output diff in cache

Signed-off-by: Matt Gleich <[email protected]>

go.mod

@@ -3,6 +3,7 @@ module go.mattglei.ch/lcp-2
 go 1.24
 
 require (
+	github.com/aymanbagabas/go-udiff v0.2.0
 	github.com/buckket/go-blurhash v1.1.0
 	github.com/caarlos0/env/v11 v11.3.1
 	github.com/joho/godotenv v1.5.1

go.sum

@@ -1,5 +1,7 @@
 github.com/aymanbagabas/go-osc52/v2 v2.0.1 h1:HwpRHbFMcZLEVr42D4p7XBqjyuxQH5SMiErDT4WkJ2k=
 github.com/aymanbagabas/go-osc52/v2 v2.0.1/go.mod h1:uYgXzlJ7ZpABp8OJ+exZzJJhRNQ2ASbcXHWsFqH8hp8=
+github.com/aymanbagabas/go-udiff v0.2.0 h1:TK0fH4MteXUDspT88n8CKzvK0X9O2xu9yQjWpi6yML8=
+github.com/aymanbagabas/go-udiff v0.2.0/go.mod h1:RE4Ex0qsGkTAJoQdQQCA0uG+nAzJO/pI/QwceO5fgrA=
 github.com/buckket/go-blurhash v1.1.0 h1:X5M6r0LIvwdvKiUtiNcRL2YlmOfMzYobI3VCKCZc9Do=
 github.com/buckket/go-blurhash v1.1.0/go.mod h1:aT2iqo5W9vu9GpyoLErKfTHwgODsZp3bQfXjXJUxNb8=
 github.com/caarlos0/env/v11 v11.3.1 h1:cArPWC15hWmEt+gWk7YBi7lEXTXCvpaSdCiZE2X5mCA=

internal/cache/cache.go

@@ -10,6 +10,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/aymanbagabas/go-udiff"
 	"go.mattglei.ch/lcp-2/internal/apis"
 	"go.mattglei.ch/lcp-2/internal/auth"
 	"go.mattglei.ch/lcp-2/internal/secrets"
@@ -59,20 +60,25 @@ func (c *Cache[T]) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 }
 
 func (c *Cache[T]) Update(data T) {
+	const jsonIndent = "  "
 	c.DataMutex.RLock()
-	old, err := json.Marshal(c.Data)
+	oldBin, err := json.MarshalIndent(c.Data, "", jsonIndent)
 	if err != nil {
 		timber.Error(err, "failed to json marshal old data")
 		return
 	}
 	c.DataMutex.RUnlock()
-	new, err := json.Marshal(data)
+	newBin, err := json.MarshalIndent(data, "", jsonIndent)
 	if err != nil {
 		timber.Error(err, "failed to json marshal new data")
 		return
 	}
 
-	if string(old) != string(new) && string(new) != "null" && strings.Trim(string(new), " ") != "" {
+	old := string(oldBin)
+	new := string(newBin)
+	if old != new && new != "null" && strings.Trim(string(newBin), " ") != "" {
+		unified := udiff.Unified("old cache", "new cache", old, new)
+		timber.Info(fmt.Sprintf("\n%s", unified))
 		c.DataMutex.Lock()
 		c.Data = data
 		c.Updated = time.Now()