Allow users to disable metrics via environment variable: 'LS_METRICS_ENABLED=false' (#154)

Author: Sergei Malafeev

CHANGELOG.md

@@ -1,5 +1,6 @@
 <a name="Pending Release"></a>
 ## [Pending Release](https://github.com/lightstep/lightstep-tracer-java-common/compare/0.30.0...master)
+* Allow users to disable metrics via environment variable: `LS_METRICS_ENABLED=false`
 
 <a name="0.30.0"></a>
 ## [0.30.0](https://github.com/lightstep/lightstep-tracer-java-common/compare/0.21.0...0.30.0)

common/pom.xml

@@ -70,15 +70,15 @@
 
         <!-- Test Dependencies -->
         <dependency>
-            <groupId>junit</groupId>
-            <artifactId>junit</artifactId>
-            <version>4.12</version>
+            <groupId>org.powermock</groupId>
+            <artifactId>powermock-module-junit4</artifactId>
+            <version>2.0.7</version>
             <scope>test</scope>
         </dependency>
         <dependency>
-            <groupId>org.mockito</groupId>
-            <artifactId>mockito-core</artifactId>
-            <version>2.18.3</version>
+            <groupId>org.powermock</groupId>
+            <artifactId>powermock-api-mockito2</artifactId>
+            <version>2.0.7</version>
             <scope>test</scope>
         </dependency>
     </dependencies>

common/src/main/java/com/lightstep/tracer/shared/LightStepConstants.java

@@ -33,6 +33,8 @@ private Metrics() {
 
         static final int DEFAULT_INTERVAL_SECS = 30;
         static final String DEFAULT_URL = "https://ingest.lightstep.com:443/metrics";
+        static final String LS_METRICS_ENABLED = "LS_METRICS_ENABLED";
+        static final boolean DEFAULT_DISABLE_METRICS = false;
     }
 
     public final class Tags {

common/src/main/java/com/lightstep/tracer/shared/Options.java

@@ -214,7 +214,7 @@ public static class OptionsBuilder {
         private Map<Format<?>, Propagator> propagators = new HashMap<>();
         private boolean disableMetaEventLogging = false;
         private String metricsUrl = LightStepConstants.Metrics.DEFAULT_URL;
-        private boolean disableMetricsReporting = false;
+        private boolean disableMetricsReporting = getEnvMetricsDisabled();
         private CollectorClient collectorClient;
         private String grpcCollectorTarget;
         private boolean grpcRoundRobin = false;
@@ -249,6 +249,14 @@ public OptionsBuilder(Options options) {
             this.okhttpDns = options.okhttpDns;
         }
 
+        private static boolean getEnvMetricsDisabled() {
+            String metricEnabled = System.getenv(LightStepConstants.Metrics.LS_METRICS_ENABLED);
+            if (metricEnabled != null) {
+                return "false".equals(metricEnabled);
+            }
+            return LightStepConstants.Metrics.DEFAULT_DISABLE_METRICS;
+        }
+
         /**
          * Adds a user defined {@link Propagator} to be used during
          * {@link io.opentracing.Tracer#inject} and {@link io.opentracing.Tracer#extract} for

common/src/test/java/com/lightstep/tracer/shared/OptionsTest.java

@@ -2,7 +2,6 @@
 
 import static com.lightstep.tracer.shared.LightStepConstants.Tags.COMPONENT_NAME_KEY;
 import static com.lightstep.tracer.shared.LightStepConstants.Tags.GUID_KEY;
-import static com.lightstep.tracer.shared.LightStepConstants.Tags.LEGACY_COMPONENT_NAME_KEY;
 import static com.lightstep.tracer.shared.LightStepConstants.Collector.DEFAULT_PLAINTEXT_PORT;
 import static com.lightstep.tracer.shared.LightStepConstants.Collector.DEFAULT_SECURE_PORT;
 import static com.lightstep.tracer.shared.LightStepConstants.Collector.PATH;
@@ -18,10 +17,9 @@
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertSame;
 import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.anyString;
 
-import io.opentracing.ScopeManager;
 import io.opentracing.propagation.Format.Builtin;
-import io.opentracing.propagation.TextMap;
 import io.opentracing.util.ThreadLocalScopeManager;
 import java.net.InetAddress;
 import java.util.Collections;
@@ -30,7 +28,16 @@
 import com.lightstep.tracer.shared.Options.OkHttpDns;
 
 import org.junit.Test;
-
+import org.junit.runner.RunWith;
+import org.mockito.Mockito;
+import org.mockito.invocation.InvocationOnMock;
+import org.mockito.stubbing.Answer;
+import org.powermock.api.mockito.PowerMockito;
+import org.powermock.core.classloader.annotations.PrepareForTest;
+import org.powermock.modules.junit4.PowerMockRunner;
+
+@RunWith(PowerMockRunner.class)
+@PrepareForTest({Options.class})
 public class OptionsTest {
     private static final String ACCESS_TOKEN = "my-access-token";
     private static final String SERVICE_VERSION = "v0.1.0";
@@ -51,6 +58,17 @@ public List<InetAddress> lookup(String hostname) {
         }
     };
 
+    private void mockSystem() {
+        PowerMockito.mockStatic(System.class);
+        Mockito.when(System.getProperty(anyString(), anyString())).thenAnswer(
+            new Answer<String>() {
+                @Override
+                public String answer(InvocationOnMock invocationOnMock) {
+                    return invocationOnMock.getArgument(1);
+                }
+            });
+    }
+
     /**
      * Basic test of OptionsBuilder that ensures if I set everything explicitly, that these values
      * are propagated to the Options object.
@@ -256,6 +274,42 @@ public void testOptionsBuilder_defaultDisableMetricsReporting() throws Exception
         assertFalse(options.disableMetricsReporting);
     }
 
+    @Test
+    public void testOptionsBuilder_disableMetricsReporting_fromEnvVariable_True() throws Exception {
+        mockSystem();
+        Mockito.when(System.getenv(LightStepConstants.Metrics.LS_METRICS_ENABLED))
+            .thenReturn("true");
+
+        Options options = new Options.OptionsBuilder()
+            .build();
+
+        assertFalse(options.disableMetricsReporting);
+    }
+
+    @Test
+    public void testOptionsBuilder_disableMetricsReporting_fromEnvVariable_False() throws Exception {
+        mockSystem();
+        Mockito.when(System.getenv(LightStepConstants.Metrics.LS_METRICS_ENABLED))
+            .thenReturn("false");
+
+        Options options = new Options.OptionsBuilder()
+            .build();
+
+        assertTrue(options.disableMetricsReporting);
+    }
+
+    @Test
+    public void testOptionsBuilder_disableMetricsReporting_fromEnvVariable_NotBoolean() throws Exception {
+        mockSystem();
+        Mockito.when(System.getenv(LightStepConstants.Metrics.LS_METRICS_ENABLED))
+            .thenReturn("not-boolean");
+
+        Options options = new Options.OptionsBuilder()
+            .build();
+
+        assertFalse(options.disableMetricsReporting);
+    }
+
     @Test
     public void testOptionsBuilder_hostname_notSet() throws Exception {
         Options options = new Options.OptionsBuilder().build();