Pull request #265: Implement healthcheck endpoint

Merge in ITB/itb-commons from feature/ITB-1624-validator-healthcheck-endpoint-for-validators to development

* commit '7872999857647d0b49ce83ec4cd351ef3a5d6956':
  Implement healthcheck endpoint

validation-commons-web/src/main/java/eu/europa/ec/itb/validation/commons/web/rest/BaseRestController.java

@@ -26,9 +26,11 @@
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PathVariable;
 
+import javax.print.attribute.standard.Media;
 import java.io.File;
 import java.io.IOException;
 import java.io.OutputStream;
@@ -100,6 +102,32 @@ public ApiInfo info(
         return ApiInfo.fromDomainConfig(domainConfig);
     }
 
+    /**
+     * Check if the validator is responding to requests.
+     *
+     * @param domain The domain.
+     * @return A 200 status code.
+     */
+    @Operation(summary = "Check if the validator is responding to requests",
+            description = "Check if the API for the given domain is available to respond to requests. " +
+                    "Can also be used as a general healthcheck, by not specifying a domain." +
+                    "This request does not return a body. Only a 200 status code if the healthcheck passes.")
+    @ApiResponse(responseCode = "200", description = "Success", content = { @Content(schema = @Schema()) })
+    @ApiResponse(responseCode = "500", description = "Error (If a problem occurred with processing the request)", content = @Content)
+    @ApiResponse(responseCode = "404", description = "Not found (for an invalid domain value)", content = @Content)
+    @GetMapping(value = {"/api/healthcheck", "/{domain}/api/healthcheck"}, consumes = MediaType.ALL_VALUE, produces = MediaType.APPLICATION_JSON_VALUE)
+    public ResponseEntity healthcheck(
+            @Parameter(name = "domain", description = "A fixed value corresponding to the specific validation domain.",
+            examples = {
+                    @ExampleObject(name="order", summary="Sample 'order' configuration", value="order", description = "The domain value to use for the demo 'order' validator."),
+                    @ExampleObject(name="any", summary="Generic 'any' configuration", value = "any", description = "The domain value to use for the generic 'any' validator used to validate content with user-provided validation artefacts.")
+            })
+            @PathVariable(value = "domain", required = false) String domain
+    ) {
+        if (domain != null && !domain.isEmpty()) validateDomain(domain);
+        return ResponseEntity.ok().build();
+    }
+
     /**
      * Validates that the domain exists.
      *

validation-commons-web/src/test/java/eu/europa/ec/itb/validation/commons/web/rest/BaseRestControllerTest.java

@@ -12,6 +12,8 @@
 import org.junit.jupiter.api.Test;
 
 import jakarta.servlet.http.HttpServletRequest;
+import org.springframework.http.HttpStatusCode;
+
 import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.IOException;
@@ -100,6 +102,12 @@ void testInfo() {
         assertEquals("Description of type2", result.getValidationTypes().get(1).getDescription());
     }
 
+    @Test
+    void testHealthcheck() {
+        assertEquals(HttpStatusCode.valueOf(200), controller.healthcheck("domain1Name").getStatusCode());
+        assertEquals(HttpStatusCode.valueOf(200), controller.healthcheck("").getStatusCode());
+    }
+
     @Test
     void testNotFound() {
         assertThrows(NotFoundException.class, () -> controller.info("domainXName"));