Apply suggestions from code review

Co-authored-by: Ikhun Um <ih.pert@gmail.com>

core/src/main/java/com/linecorp/armeria/client/observation/DefaultHttpClientObservationConvention.java

@@ -42,8 +42,8 @@ public KeyValues getLowCardinalityKeyValues(HttpClientContext context) {
  final ClientRequestContext ctx = context.requestContext();
  KeyValues keyValues = KeyValues.of(
  LowCardinalityKeys.HTTP_METHOD.withValue(ctx.method().name()));
- if (context.getResponse() != null) {
-  final RequestLog log = ctx.log().ensureComplete();
+ final RequestLog log = context.getResponse();
+ if (log != null) {
  keyValues = keyValues.and(LowCardinalityKeys.HTTP_PROTOCOL.withValue(protocol(log)));
  final String serFmt = serializationFormat(log);
  if (serFmt != null) {
@@ -89,15 +89,15 @@ public KeyValues getHighCardinalityKeyValues(HttpClientContext context) {
  * Returns the {@link SessionProtocol#uriText()} of the {@link RequestLog}.
  */
  private static String protocol(RequestLog requestLog) {
- return requestLog.scheme().sessionProtocol().uriText();
+ return requestLog.sessionProtocol().uriText();
  }
 
  /**
  * Returns the {@link SerializationFormat#uriText()} if it's not {@link SerializationFormat#NONE}.
  */
  @Nullable
  private static String serializationFormat(RequestLog requestLog) {
- final SerializationFormat serFmt = requestLog.scheme().serializationFormat();
+ final SerializationFormat serFmt = requestLog.serializationFormat();
  return serFmt == SerializationFormat.NONE ? null : serFmt.uriText();
  }
 

core/src/main/java/com/linecorp/armeria/client/observation/MicrometerObservationClient.java

@@ -76,6 +76,7 @@ public final class MicrometerObservationClient extends SimpleDecoratingHttpClien
  */
  public static Function<? super HttpClient, MicrometerObservationClient> newDecorator(
  ObservationRegistry observationRegistry) {
+ requireNonNull(observationRegistry, "observationRegistry");
  return delegate -> new MicrometerObservationClient(delegate, observationRegistry, null);
  }
 
@@ -111,7 +112,7 @@ public HttpResponse execute(ClientRequestContext ctx, HttpRequest req) throws Ex
  final RequestHeadersBuilder newHeaders = req.headers().toBuilder();
  final HttpClientContext httpClientContext = new HttpClientContext(ctx, newHeaders, req);
  final Observation observation = HttpClientObservationDocumentation.OBSERVATION.observation(
- this.httpClientObservationConvention, DefaultHttpClientObservationConvention.INSTANCE,
+ httpClientObservationConvention, DefaultHttpClientObservationConvention.INSTANCE,
  () -> httpClientContext, observationRegistry).start();
  final HttpRequest newReq = req.withHeaders(newHeaders);
  ctx.updateRequest(newReq);
@@ -127,7 +128,7 @@ public HttpResponse execute(ClientRequestContext ctx, HttpRequest req) throws Ex
  return observation.scopedChecked(() -> unwrap().execute(ctx, newReq));
  }
 
- private void enrichObservation(ClientRequestContext ctx, HttpClientContext httpClientContext,
+ private static void enrichObservation(ClientRequestContext ctx, HttpClientContext httpClientContext,
  Observation observation) {
  if (observation.isNoop()) {
  // For no-op spans, we only need to inject into headers and don't set any other attributes.

core/src/main/java/com/linecorp/armeria/server/observation/DefaultServiceObservationConvention.java

@@ -66,8 +66,8 @@ public KeyValues getHighCardinalityKeyValues(HttpServerContext context) {
  firstNonNull(context.httpRequest().authority(), "UNKNOWN")),
  HighCardinalityKeys.HTTP_URL.withValue(ctx.uri().toString())
  );
- if (context.getResponse() != null) {
-  final RequestLog log = ctx.log().ensureComplete();
+ final RequestLog log = context.getResponse();
+ if (log != null) {
 
  final InetSocketAddress raddr = ctx.remoteAddress();
  keyValues = keyValues.and(
@@ -92,15 +92,15 @@ public KeyValues getHighCardinalityKeyValues(HttpServerContext context) {
  * Returns the {@link SessionProtocol#uriText()} of the {@link RequestLog}.
  */
  private static String protocol(RequestLog requestLog) {
- return requestLog.scheme().sessionProtocol().uriText();
+ return requestLog.sessionProtocol().uriText();
  }
 
  /**
  * Returns the {@link SerializationFormat#uriText()} if it's not {@link SerializationFormat#NONE}.
  */
  @Nullable
  private static String serializationFormat(RequestLog requestLog) {
- final SerializationFormat serFmt = requestLog.scheme().serializationFormat();
+ final SerializationFormat serFmt = requestLog.serializationFormat();
  return serFmt == SerializationFormat.NONE ? null : serFmt.uriText();
  }
 

core/src/main/java/com/linecorp/armeria/server/observation/HttpServerObservationDocumentation.java

@@ -26,7 +26,7 @@
 import io.micrometer.observation.ObservationConvention;
 import io.micrometer.observation.docs.ObservationDocumentation;
 
-enum HttpServerObservationDocumentation implements ObservationDocumentation {
+enum HttpServiceObservationDocumentation implements ObservationDocumentation {
 
  /**
  * A span collected by {@link MicrometerObservationService}.

core/src/main/java/com/linecorp/armeria/server/observation/MicrometerObservationService.java

@@ -67,14 +67,15 @@
  * }</pre>
  */
 @UnstableApi
-public final class MicrometerObservationService extends SimpleDecoratingHttpService {
+public final class ObservationService extends SimpleDecoratingHttpService {
 
  /**
  * Creates a new micrometer observation integrated {@link HttpService} decorator using the
  * specified {@link ObservationRegistry} instance.
  */
  public static Function<? super HttpService, MicrometerObservationService>
  newDecorator(ObservationRegistry observationRegistry) {
+ requireNonNull(observationRegistry, "observationRegistry");
  return service -> new MicrometerObservationService(service, observationRegistry, null);
  }