health: add logstash.forceApiStatus: green escape hatch (#16535)

elastic · Oct 10, 2024 · 0657696 · 0657696
1 parent 4037adf
commit 0657696
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diff --git a/logstash-core/src/main/java/org/logstash/health/HealthObserver.java b/logstash-core/src/main/java/org/logstash/health/HealthObserver.java
@@ -25,6 +25,8 @@ public class HealthObserver {
 
     private static final Logger LOGGER = LogManager.getLogger();
 
+    static final String FORCE_API_STATUS_PROPERTY = "logstash.forceApiStatus";
+
     private final MultiIndicator rootIndicator = new MultiIndicator();
     private final MultiIndicator pipelinesIndicator = new MultiIndicator();
 
@@ -33,6 +35,15 @@ public HealthObserver() {
     }
 
     public final Status getStatus() {
+        // Short-term escape-hatch
+        final String forceApiStatus = System.getProperty(FORCE_API_STATUS_PROPERTY);
+        if (forceApiStatus != null) {
+            if (forceApiStatus.equals("green")) {
+                return Status.GREEN;
+            } else {
+                LOGGER.warn("Unsupported `logstash.forceApiStatus`: {} (health report status will be propagated)", forceApiStatus);
+            }
+        }
         return getReport().getStatus();
     }
 

diff --git a/logstash-core/src/test/java/org/logstash/health/HealthObserverTest.java b/logstash-core/src/test/java/org/logstash/health/HealthObserverTest.java
@@ -0,0 +1,93 @@
+package org.logstash.health;
+
+import org.hamcrest.Matchers;
+import org.junit.Test;
+
+import java.util.Objects;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.logstash.health.HealthObserver.FORCE_API_STATUS_PROPERTY;
+
+public class HealthObserverTest {
+
+    private final HealthObserver healthObserver = new HealthObserver();
+
+    @Test
+    public void testStatusWhenNotForcedPropagates() {
+        withUnsetSystemProperty(FORCE_API_STATUS_PROPERTY, () -> {
+            for (Status reportStatus : Status.values()) {
+                withIndicator(new TestIndicator(reportStatus), () -> {
+                    assertThat(String.format("Status[%s] should propagate", reportStatus), healthObserver.getStatus(), Matchers.is(reportStatus));
+                });
+            }
+        });
+    }
+
+    @Test
+    public void testStatusWhenForcedGreenEmitsGreen() {
+        withSystemProperty(FORCE_API_STATUS_PROPERTY, "green", () -> {
+            for (Status reportStatus : Status.values()) {
+                withIndicator(new TestIndicator(reportStatus), () -> {
+                    assertThat(String.format("Status[%s] should not propagate", reportStatus), healthObserver.getStatus(), Matchers.is(Status.GREEN));
+                });
+            }
+        });
+    }
+
+    @Test
+    public void testStatusWhenForcedNonsensePropagates() {
+        withSystemProperty(FORCE_API_STATUS_PROPERTY, "nonsense", () -> {
+            for (Status reportStatus : Status.values()) {
+                withIndicator(new TestIndicator(reportStatus), () -> {
+                    assertThat(String.format("Status[%s] should propagate", reportStatus), healthObserver.getStatus(), Matchers.is(reportStatus));
+                });
+            }
+        });
+    }
+
+    void withUnsetSystemProperty(final String propertyName, final Runnable action) {
+        withSystemProperty(propertyName, null, action);
+    }
+
+    void withSystemProperty(final String name, final String value, final Runnable action) {
+        synchronized (System.class) {
+            final String oldValue;
+            if (Objects.isNull(value)) {
+                oldValue = System.clearProperty(name);
+            } else {
+                oldValue = System.setProperty(name, value);
+            }
+            try {
+                action.run();
+            } finally {
+                if (oldValue != null) {
+                    System.setProperty(name, oldValue);
+                } else {
+                    System.clearProperty(name);
+                }
+            }
+        }
+    }
+
+    void withIndicator(Indicator<?> indicator, Runnable runnable) {
+        this.healthObserver.getIndicator().attachIndicator("single", indicator);
+        try {
+            runnable.run();
+        } finally {
+            this.healthObserver.getIndicator().detachIndicator("single", indicator);
+        }
+    }
+
+    static class TestIndicator implements Indicator<Indicator.Report> {
+        private final Status status;
+
+        public TestIndicator(final Status status) {
+            this.status = status;
+        }
+
+        @Override
+        public Report report(ReportContext reportContext) {
+            return () -> this.status;
+        }
+    }
+}