fix: add proper logging to log ingestion endpoint

Previously the endpoint silently returned 202 for all failures: missing
agent identity, unregistered agents, empty payloads, and buffer-full
drops. Now logs WARN for each failure case with context (instanceId,
entry count, reason). Normal ingestion logged at INFO with accepted
count. Buffer-full drops tracked individually with accepted/dropped
counts.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cameleer3-server-app/src/main/java/com/cameleer3/server/app/controller/LogIngestionController.java

@@ -45,32 +45,57 @@ public class LogIngestionController {
     @ApiResponse(responseCode = "202", description = "Logs accepted for indexing")
     public ResponseEntity<Void> ingestLogs(@RequestBody List<LogEntry> entries) {
         String instanceId = extractAgentId();
-        String applicationId = resolveApplicationId(instanceId);
+        if (instanceId == null || instanceId.isBlank()) {
+            log.warn("Log ingestion rejected: no agent identity in request (unauthenticated or missing principal)");
+            return ResponseEntity.accepted().build();
+        }
 
-        if (entries != null && !entries.isEmpty()) {
+        if (entries == null || entries.isEmpty()) {
-            log.debug("Received {} log entries from instance={}, app={}", entries.size(), instanceId, applicationId);
+            log.warn("Log ingestion from instance={}: empty or null payload", instanceId);
-            String environment = resolveEnvironment(instanceId);
+            return ResponseEntity.accepted().build();
-            for (var entry : entries) {
+        }
-                logBuffer.offerOrWarn(new BufferedLogEntry(
+
-                        tenantProperties.getId(), environment, instanceId, applicationId, entry));
+        AgentInfo agent = registryService.findById(instanceId);
+        if (agent == null) {
+            log.warn("Log ingestion from instance={}: agent not found in registry (not registered or expired). {} entries dropped.",
+                    instanceId, entries.size());
+            return ResponseEntity.accepted().build();
+        }
+
+        String applicationId = agent.applicationId();
+        String environment = agent.environmentId() != null ? agent.environmentId() : "default";
+
+        if (applicationId == null || applicationId.isBlank()) {
+            log.warn("Log ingestion from instance={}: agent has no applicationId. {} entries dropped.", instanceId, entries.size());
+            return ResponseEntity.accepted().build();
+        }
+
+        log.debug("Ingesting {} log entries from instance={}, app={}, env={}", entries.size(), instanceId, applicationId, environment);
+
+        int accepted = 0;
+        int dropped = 0;
+        for (var entry : entries) {
+            boolean offered = logBuffer.offer(new BufferedLogEntry(
+                    tenantProperties.getId(), environment, instanceId, applicationId, entry));
+            if (offered) {
+                accepted++;
+            } else {
+                dropped++;
             }
         }
 
+        if (dropped > 0) {
+            log.warn("Log buffer full: accepted={}, dropped={} from instance={}, app={}",
+                    accepted, dropped, instanceId, applicationId);
+        } else {
+            log.info("Accepted {} log entries from instance={}, app={}", accepted, instanceId, applicationId);
+        }
+
         return ResponseEntity.accepted().build();
     }
 
     private String extractAgentId() {
         Authentication auth = SecurityContextHolder.getContext().getAuthentication();
-        return auth != null ? auth.getName() : "";
+        return auth != null ? auth.getName() : null;
-    }
-
-    private String resolveApplicationId(String instanceId) {
-        AgentInfo agent = registryService.findById(instanceId);
-        return agent != null ? agent.applicationId() : "";
-    }
-
-    private String resolveEnvironment(String instanceId) {
-        AgentInfo agent = registryService.findById(instanceId);
-        return agent != null && agent.environmentId() != null ? agent.environmentId() : "default";
     }
 }