Add code to capture caller stack frames

bannmann · Nov 28, 2023 · d8c3121 · d8c3121
1 parent 5686542
commit d8c3121
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Showing 5 changed files with 50 additions and 6 deletions.
diff --git a/src/main/java/dev/bannmann/restflow/AbstractRequester.java b/src/main/java/dev/bannmann/restflow/AbstractRequester.java
@@ -2,14 +2,17 @@
 
 import java.net.http.HttpRequest;
 import java.net.http.HttpResponse;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
+import java.util.stream.Stream;
 
 import lombok.RequiredArgsConstructor;
 
+import com.google.common.collect.ImmutableList;
 import dev.failsafe.Failsafe;
 import dev.failsafe.Policy;
 
@@ -20,6 +23,8 @@ abstract class AbstractRequester<B, R> implements Requester<R>
     protected final ClientConfig clientConfig;
     protected final ConcurrentMap<String, Object> diagnosticsData = new ConcurrentHashMap<>();
 
+    private ImmutableList<StackWalker.StackFrame> callerFrames;
+
     @Override
     public final CompletableFuture<R> start()
     {
@@ -30,9 +35,24 @@ public final CompletableFuture<R> start()
             diagnosticsData.putAll(values);
         }
 
+        int callerFrameCount = clientConfig.getCallerFrameCount();
+        if (callerFrameCount > 0)
+        {
+            var stackWalker = StackWalker.getInstance(Collections.emptySet(), callerFrameCount);
+            callerFrames = stackWalker.walk(stream -> captureCallerFrames(callerFrameCount, stream));
+        }
+
         return send().thenApply(this::extractValue);
     }
 
+    private ImmutableList<StackWalker.StackFrame> captureCallerFrames(int count, Stream<StackWalker.StackFrame> stream)
+    {
+        return stream.dropWhile(stackFrame -> stackFrame.getClassName()
+                .startsWith(getClass().getPackageName()))
+            .limit(count)
+            .collect(ImmutableList.toImmutableList());
+    }
+
     private CompletableFuture<HttpResponse<B>> send()
     {
         List<Policy<HttpResponse<?>>> policies = clientConfig.getPolicies();
@@ -60,7 +80,7 @@ private <T> T addDetailsForLowLevelExceptions(T result, Throwable throwable)
         if (throwable != null)
         {
             String message = String.format("Request to URL %s failed", request.uri());
-            throw new RequestFailureException(request, message, throwable, diagnosticsData);
+            throw new RequestFailureException(request, message, throwable, diagnosticsData, callerFrames);
         }
         return result;
     }

diff --git a/src/main/java/dev/bannmann/restflow/ClientConfig.java b/src/main/java/dev/bannmann/restflow/ClientConfig.java
@@ -33,4 +33,14 @@ public final class ClientConfig
 
     @Singular
     private final List<RequestCustomizer> requestCustomizers;
+
+    /**
+     * The number of caller stack frames to capture when starting a request. The captured frames will be included in
+     * any {@link RequestException} (or subclass) instance thrown by restflow. This is useful if the application is
+     * supposed to log intermediate exceptions, which will otherwise not carry any stack information relating to the
+     * original thread (due to neither being thrown there nor being set as the cause of an exception thrown in that
+     * thread).
+     */
+    @Builder.Default
+    private final int callerFrameCount = 5;
 }
diff --git a/src/main/java/dev/bannmann/restflow/RequestException.java b/src/main/java/dev/bannmann/restflow/RequestException.java
@@ -1,6 +1,7 @@
 package dev.bannmann.restflow;
 
 import java.net.http.HttpRequest;
+import java.util.List;
 import java.util.Map;
 
 import lombok.Getter;
@@ -14,12 +15,18 @@ public abstract class RequestException extends RuntimeException
 {
     private final transient HttpRequest request;
     private final transient Map<String, Object> diagnosticsData;
+    private final transient List<StackWalker.StackFrame> callerFrames;
 
     protected RequestException(
-        HttpRequest request, String message, Throwable cause, Map<String, Object> diagnosticsData)
+        HttpRequest request,
+        String message,
+        Throwable cause,
+        Map<String, Object> diagnosticsData,
+        List<StackWalker.StackFrame> callerFrames)
     {
         super(message, cause);
         this.request = request;
         this.diagnosticsData = diagnosticsData;
+        this.callerFrames = callerFrames;
     }
 }
diff --git a/src/main/java/dev/bannmann/restflow/RequestFailureException.java b/src/main/java/dev/bannmann/restflow/RequestFailureException.java
@@ -1,6 +1,7 @@
 package dev.bannmann.restflow;
 
 import java.net.http.HttpRequest;
+import java.util.List;
 import java.util.Map;
 
 /**
@@ -11,8 +12,12 @@
 public class RequestFailureException extends RequestException
 {
     public RequestFailureException(
-        HttpRequest request, String message, Throwable cause, Map<String, Object> diagnosticsData)
+        HttpRequest request,
+        String message,
+        Throwable cause,
+        Map<String, Object> diagnosticsData,
+        List<StackWalker.StackFrame> callerFrames)
     {
-        super(request, message, cause, diagnosticsData);
+        super(request, message, cause, diagnosticsData, callerFrames);
     }
 }
diff --git a/src/main/java/dev/bannmann/restflow/RequestStatusException.java b/src/main/java/dev/bannmann/restflow/RequestStatusException.java
@@ -2,6 +2,7 @@
 
 import java.net.http.HttpRequest;
 import java.net.http.HttpResponse;
+import java.util.List;
 import java.util.Map;
 
 import lombok.Builder;
@@ -27,9 +28,10 @@ public RequestStatusException(
         HttpResponse<?> response,
         int status,
         String body,
-        Map<String, Object> diagnosticsData)
+        Map<String, Object> diagnosticsData,
+        List<StackWalker.StackFrame> callerFrames)
     {
-        super(request, message, cause, diagnosticsData);
+        super(request, message, cause, diagnosticsData, callerFrames);
 
         this.response = response;
         this.status = status;