chore: Reuse DotEnv instance and reduce log messages (#635)

* Add 5min cache to service binding loader

* Change solution to cache DotEnv instance instead of ServiceBinding(Accessor); And consider log level dynamically

* Formatting

* Add line-break

* Update release_notes.md

* Update log message format.

---------

Co-authored-by: SAP Cloud SDK Bot <[email protected]>

Author: newtork

core/src/main/java/com/sap/ai/sdk/core/AiCoreService.java

@@ -43,9 +43,7 @@ public class AiCoreService {
 
   /** The default constructor. */
   public AiCoreService() {
-    val resolver = new DestinationResolver();
-    this.baseDestinationResolver = resolver::getDestination;
-    this.deploymentResolver = new DeploymentResolver(this);
+    this(new DestinationResolver()::getDestination);
   }
 
   AiCoreService(@Nonnull final Supplier<HttpDestination> baseDestinationResolver) {

core/src/main/java/com/sap/ai/sdk/core/AiCoreServiceKeyAccessor.java

@@ -17,6 +17,7 @@
 import lombok.AllArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import lombok.val;
+import org.slf4j.event.Level;
 
 /**
  * Loads an AI Core service key from the "AICORE_SERVICE_KEY" environment variable with support for
@@ -27,10 +28,13 @@
 class AiCoreServiceKeyAccessor implements ServiceBindingAccessor {
   static final String ENV_VAR_KEY = "AICORE_SERVICE_KEY";
 
+  private static final Lazy<Dotenv> DEFAULT_DOTENV =
+      Lazy.of(() -> Dotenv.configure().ignoreIfMissing().ignoreIfMalformed().load());
+
   private final Lazy<Dotenv> dotenv;
 
   AiCoreServiceKeyAccessor() {
-    this(Dotenv.configure().ignoreIfMissing().ignoreIfMalformed());
+    this(DEFAULT_DOTENV);
   }
 
   AiCoreServiceKeyAccessor(@Nonnull final DotenvBuilder dotenvBuilder) {
@@ -41,6 +45,7 @@ class AiCoreServiceKeyAccessor implements ServiceBindingAccessor {
   @Override
   public List<ServiceBinding> getServiceBindings() throws ServiceBindingAccessException {
     final String serviceKey;
+    final Level logLevel = dotenv.isEvaluated() ? Level.TRACE : Level.INFO;
     try {
       serviceKey = dotenv.get().get(ENV_VAR_KEY);
     } catch (Exception e) {
@@ -50,13 +55,11 @@ public List<ServiceBinding> getServiceBindings() throws ServiceBindingAccessExce
       log.debug("No service key found in environment variable {}", ENV_VAR_KEY);
       return List.of();
     }
-    log.info(
-        """
-        Found a service key in environment variable {}.
-        Using a service key is recommended for local testing only.
-        Bind the AI Core service to the application for productive usage.
-        """,
-        ENV_VAR_KEY);
+    final String logMessage =
+        "Found a service key in environment variable {}. "
+            + "Using a service key is recommended for local testing only."
+            + "Bind the AI Core service to the application for productive usage.";
+    log.atLevel(logLevel).log(logMessage, ENV_VAR_KEY);
 
     val binding = createServiceBinding(serviceKey);
     return List.of(binding);

docs/release_notes.md

@@ -17,7 +17,7 @@
 ### 📈 Improvements
 
 - [Core] If the AI Core credentials used are missing an explicit `credential-type` but `clientid` and `clientsecret` are present then `"credential-type": "binding-secret"` is inferred automatically.
-
+- [Core] Log message about "service key in environment variable" to `INFO` level only once.
 
 ### 🐛 Fixed Issues