add ReadinessController

src/main/java/no/fintlabs/provider/ReadinessController.java

@@ -0,0 +1,34 @@
+package no.fintlabs.provider;
+
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import no.fintlabs.provider.kafka.offset.OffsetState;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.client.RestClientResponseException;
+
+@Slf4j
+@RestController
+@RequiredArgsConstructor
+@RequestMapping("/ready")
+public class ReadinessController {
+
+    private final OffsetState offsetState;
+    private final ProviderClient providerClient;
+
+    @GetMapping
+    public ResponseEntity<Void> readinessCheck() {
+        try {
+            return offsetState.equals(providerClient.getExistingOffsetState())
+                    ? ResponseEntity.ok().build()
+                    : ResponseEntity.status(HttpStatus.SERVICE_UNAVAILABLE).build();
+        } catch (RestClientResponseException e) {
+            log.error("Failed fetching readiness check with status code: {}", e.getStatusCode());
+            return ResponseEntity.ok().build();
+        }
+    }
+
+}