Changed accept to reject and added a list of filters

docs/src/main/asciidoc/spring-cloud-sleuth.adoc

@@ -951,18 +951,21 @@ object, you will have to create a bean of `zipkin2.reporter.Sender` type.
 
 There are cases when you might not want to report a given span e.g. to Zipkin.
 In order to filter out spans, you should implement the `SpanFilter` interface
-which returns `true` if a span should be reported and `false` otherwise. Example:
+which returns `true` if a span should be NOT be reported and `false` otherwise. Example:
 
 [source,java]
 ----
 	@Bean SpanFilter mySpanFilter() {
 		return (span) -> {
-		    // true - if we want span to be reported
+		    // true - if we want span NOT to be reported
 		    // false - otherwise
 		};
 	}
 ----
 
+You can have multiple `SpanFilter`s and the whole list of them will be applied
+against the span that is to be reported.
+
 == Zipkin Stream Span Consumer
 
 IMPORTANT: We recommend using Zipkin's native support for message-based span sending.

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/SpanFilter.java

@@ -31,7 +31,7 @@ public interface SpanFilter {
 
 	/**
 	 * @param span - span to be reported
-	 * @return - {@code true} if span is to be reported, {@code false} otherwise
+	 * @return - {@code true} if span is to be rejected, {@code false} otherwise
 	 */
-	boolean accept(Span span);
+	boolean reject(Span span);
 }

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/autoconfig/TraceAutoConfiguration.java

@@ -63,6 +63,7 @@ public class TraceAutoConfiguration {
 	public static final String TRACER_BEAN_NAME = "tracer";
 
 	@Autowired(required = false) List<SpanAdjuster> spanAdjusters = new ArrayList<>();
+	@Autowired(required = false) List<SpanFilter> spanFilters = new ArrayList<>();
 
 	@Bean
 	@ConditionalOnMissingBean
@@ -73,37 +74,42 @@ Tracing tracing(@Value("${spring.zipkin.service.name:${spring.application.name:d
 			Reporter<zipkin2.Span> reporter,
 			Sampler sampler,
 			ErrorParser errorParser,
-			SleuthProperties sleuthProperties,
-			SpanFilter spanFilter
+			SleuthProperties sleuthProperties
 	) {
 		return Tracing.newBuilder()
 				.sampler(sampler)
 				.errorParser(errorParser)
 				.localServiceName(serviceName)
 				.propagationFactory(factory)
 				.currentTraceContext(currentTraceContext)
-				.spanReporter(adjustedReporter(reporter, spanFilter))
+				.spanReporter(adjustedReporter(reporter))
 				.traceId128Bit(sleuthProperties.isTraceId128())
 				.supportsJoin(sleuthProperties.isSupportsJoin())
 				.build();
 	}
 
-	private Reporter<zipkin2.Span> adjustedReporter(Reporter<zipkin2.Span> delegate, SpanFilter spanFilter) {
+	private Reporter<zipkin2.Span> adjustedReporter(Reporter<zipkin2.Span> delegate) {
 		return span -> {
-			Span spanToAdjust = span;
-			for (SpanAdjuster spanAdjuster : this.spanAdjusters) {
-				spanToAdjust = spanAdjuster.adjust(spanToAdjust);
-			}
-			if (spanFilter.accept(spanToAdjust)) {
-				delegate.report(spanToAdjust);
-			} else {
+			Span spanToAdjust = spanToAdjust(span);
+			if (this.spanFilters.stream()
+					.anyMatch(filter -> filter.reject(spanToAdjust))) {
 				if (log.isDebugEnabled()) {
 					log.debug("Span [" + spanToAdjust + "] filtered and will not be reported");
 				}
+			} else {
+				delegate.report(spanToAdjust);
 			}
 		};
 	}
 
+	private Span spanToAdjust(Span span) {
+		Span spanToAdjust = span;
+		for (SpanAdjuster spanAdjuster : this.spanAdjusters) {
+			spanToAdjust = spanAdjuster.adjust(spanToAdjust);
+		}
+		return spanToAdjust;
+	}
+
 	@Bean(name = TRACER_BEAN_NAME)
 	@ConditionalOnMissingBean
 	Tracer tracer(Tracing tracing) {
@@ -123,7 +129,7 @@ Sampler sleuthTraceSampler() {
 
 	@Bean
 	@ConditionalOnMissingBean SpanFilter noOpSpanFilter() {
-		return (span) -> true;
+		return (span) -> false;
 	}
 
 	@Bean

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/web/TraceFilterIntegrationTests.java

@@ -89,7 +89,7 @@ public class TraceFilterIntegrationTests extends AbstractMvcIntegrationTest {
 	@Before
 	@After
 	public void clear() {
-		this.mySpanFilter.enableAll = true;
+		this.mySpanFilter.disableAll = false;
 		this.reporter.clear();
 	}
 
@@ -230,7 +230,7 @@ public void should_return_custom_response_headers_when_custom_trace_filter_gets_
 	@Test
 	public void should_filter_out_a_span_and_not_report_it() throws Exception {
 		Long expectedTraceId = new Random().nextLong();
-		this.mySpanFilter.enableAll = false;
+		this.mySpanFilter.disableAll = true;
 		this.mySpanFilter.wasCalled = false;
 
 		whenSentPongWithTraceId(expectedTraceId);
@@ -435,11 +435,11 @@ class MyFilter extends GenericFilterBean {
 
 class MySpanFilter implements SpanFilter {
 
-	boolean enableAll = true;
+	boolean disableAll = false;
 	boolean wasCalled = false;
 
-	@Override public boolean accept(zipkin2.Span span) {
+	@Override public boolean reject(zipkin2.Span span) {
 		this.wasCalled = true;
-		return this.enableAll;
+		return this.disableAll;
 	}
 }