Implemented default LoggingExporter for trace api

scm-core/src/main/java/sonia/scm/trace/Span.java

@@ -24,7 +24,6 @@
 
 package sonia.scm.trace;
 
-import java.time.Clock;
 import java.time.Instant;
 import java.util.Collections;
 import java.util.LinkedHashMap;
@@ -37,7 +36,6 @@ import java.util.Map;
  */
 public final class Span implements AutoCloseable {
 
-  private final Clock clock;
   private final Tracer tracer;
   private final String kind;
   private final Map<String,String> labels = new LinkedHashMap<>();
@@ -45,14 +43,9 @@ public final class Span implements AutoCloseable {
   private boolean failed;
 
   Span(Tracer tracer, String kind) {
-    this(tracer, kind, Clock.systemUTC());
-  }
-
-  Span(Tracer tracer, String kind, Clock clock) {
-    this.clock = clock;
     this.tracer = tracer;
     this.kind = kind;
-    this.opened = clock.instant();
+    this.opened = Instant.now();
   }
 
   /**
@@ -142,7 +135,7 @@ public final class Span implements AutoCloseable {
    */
   @Override
   public void close() {
-    tracer.export(new SpanContext(kind, Collections.unmodifiableMap(labels), opened, clock.instant(), failed));
+    tracer.export(new SpanContext(kind, Collections.unmodifiableMap(labels), opened, Instant.now(), failed));
   }
 
 }

scm-core/src/main/java/sonia/scm/trace/SpanContext.java

@@ -24,8 +24,6 @@
 
 package sonia.scm.trace;
 
-import lombok.AccessLevel;
-import lombok.AllArgsConstructor;
 import lombok.Value;
 
 import java.time.Duration;
@@ -33,12 +31,12 @@ import java.time.Instant;
 import java.util.Map;
 
 /**
- * The {@link SpanContext} represents a finsished span which could be processed by an {@link Exporter}.
+ * The {@link SpanContext} represents a finished span which could be processed by an {@link Exporter}.
+ *
  * @since 2.9.0
  */
 @Value
-@AllArgsConstructor(access = AccessLevel.PACKAGE)
-public final class SpanContext {
+public class SpanContext {
 
   String kind;
   Map<String,String> labels;

scm-core/src/test/java/sonia/scm/trace/TracerTest.java

@@ -34,7 +34,6 @@ import java.util.Map;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
-
 class TracerTest {
 
   private Tracer tracer;
@@ -63,8 +62,6 @@ class TracerTest {
     try (Span span = tracer.span("sample")) {
       span.label("l1", "one");
       Thread.sleep(1L);
-    } catch (Exception ex) {
-      span.
     }
 
     SpanContext span = exporter.spans.get(0);

scm-webapp/src/main/java/sonia/scm/trace/LoggingExporter.java

@@ -0,0 +1,78 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020-present Cloudogu GmbH and Contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package sonia.scm.trace;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import sonia.scm.plugin.Extension;
+
+import javax.inject.Inject;
+import java.util.Map;
+import java.util.function.Consumer;
+
+/**
+ * An {@link Exporter} which logs every collected span.
+ *
+ * @since 2.9.0
+ */
+@Extension
+public final class LoggingExporter implements Exporter {
+
+  private static final Logger LOG = LoggerFactory.getLogger(LoggingExporter.class);
+
+  private final Consumer<String> logger;
+
+  @Inject
+  LoggingExporter() {
+    this(LOG::info);
+  }
+
+  LoggingExporter(Consumer<String> logger) {
+    this.logger = logger;
+  }
+
+  @Override
+  public void export(SpanContext span) {
+    logger.accept(format(span));
+  }
+
+  private String format(SpanContext span) {
+    StringBuilder message = new StringBuilder("received ");
+    if (span.isFailed()) {
+      message.append("failed ");
+    }
+    message.append(span.getKind()).append(" span, which took ");
+    message.append(span.duration().toMillis()).append("ms");
+    Map<String, String> labels = span.getLabels();
+    if (!labels.isEmpty()) {
+      message.append(":");
+      for (Map.Entry<String, String> e : labels.entrySet()) {
+        message.append("\n - ").append(e.getKey()).append(": ").append(e.getValue());
+      }
+    }
+    return message.toString();
+  }
+
+}

scm-webapp/src/test/java/sonia/scm/trace/LoggingExporterTest.java

@@ -0,0 +1,88 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020-present Cloudogu GmbH and Contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package sonia.scm.trace;
+
+import com.google.common.collect.ImmutableMap;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.time.Instant;
+import java.util.Collections;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class LoggingExporterTest {
+
+  private String message;
+
+  private LoggingExporter exporter;
+
+  @BeforeEach
+  void setUpLogger() {
+    exporter = new LoggingExporter((message) -> this.message = message);
+  }
+
+  @Test
+  void shouldLogTheSpanKind() {
+    exporter.export(new SpanContext(
+      "AwesomeSpanKind", Collections.emptyMap(), Instant.now(), Instant.now(), false
+    ));
+
+    assertThat(message).contains("AwesomeSpanKind");
+  }
+
+  @Test
+  void shouldLogFailed() {
+    exporter.export(new SpanContext(
+      "sample", Collections.emptyMap(), Instant.now(), Instant.now(), true
+    ));
+
+    assertThat(message).contains("failed");
+  }
+
+  @Test
+  void shouldLogDuration() {
+    Instant opened = Instant.now();
+    exporter.export(new SpanContext(
+      "sample", ImmutableMap.of(), opened, opened.plusMillis(42L), false
+    ));
+
+    assertThat(message).contains("42ms");
+  }
+
+  @Test
+  void shouldLogLabels() {
+    exporter.export(new SpanContext(
+      "sample", ImmutableMap.of("l1", "v1", "l2", "v2"), Instant.now(), Instant.now(), false
+    ));
+
+    assertThat(message)
+      .contains("l1")
+      .contains("v1")
+      .contains("l2")
+      .contains("v2");
+  }
+
+}