Add fleet level disable decider logic

singer/src/main/java/com/pinterest/singer/config/Decider.java

@@ -16,6 +16,7 @@
 package com.pinterest.singer.config;
 
 import com.pinterest.singer.utils.HashUtils;
+import com.pinterest.singer.utils.SingerUtils;
 
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Strings;
@@ -103,6 +104,11 @@ public Map<String, Integer> getDeciderMap() {
     return mDeciderMap;
   }
 
+  public static String generateDisableDecider(String logName) {
+    return "singer_disable_" + logName + "___"
+        + SingerUtils.getHostnamePrefix().replace('-', '_') + "___decider";
+  }
+
   /**
    * Looks up the value of the decider variable named {@code deciderName} and flips a coin to
    * determine if we should be in the experiment based on the specified ID. Useful if a stable

singer/src/main/java/com/pinterest/singer/processor/DefaultLogStreamProcessor.java

@@ -68,6 +68,9 @@ public class DefaultLogStreamProcessor implements LogStreamProcessor, Runnable {
   // Decider for the log stream.
   private final String logDecider;
 
+  // Decider used in conjunction with logDecider to disable the logstream at a fleet level
+  private final String fleetDisableDecider;
+
   // LogStream to be processed.
   protected final LogStream logStream;
 
@@ -165,6 +168,9 @@ public DefaultLogStreamProcessor(
     this.exceedTimeSliceLimit = false;
     this.lastModificationTimeProcessed = new AtomicLong(-1);
     this.lastCompletedCycleTime = new AtomicLong(-1);
+    this.fleetDisableDecider =
+        Decider.generateDisableDecider(logStream.getSingerLog().getSingerLogConfig().getName()
+            .replaceAll("[^a-zA-Z0-9]", "_"));
   }
 
   @Override
@@ -252,6 +258,11 @@ boolean isLoggingAllowedByDecider() {
       if (map.containsKey(logDecider)) {
         result = map.get(logDecider) != 0;
       }
+      if (result && map.containsKey(fleetDisableDecider) && map.get(fleetDisableDecider) == 100) {
+        LOG.info("Disabling log stream {} because fleet disable decider {} is set to 100", logStream.getLogStreamName(),
+            fleetDisableDecider);
+        result = false;
+      }
     }
     return result;
   }

singer/src/main/java/com/pinterest/singer/utils/SingerUtils.java

@@ -91,6 +91,23 @@ public static String getHostname() {
     return hostName;
   }
 
+  /**
+   * @return the prefix of the host name
+   */
+  public static String getHostnamePrefix() {
+    String hostNameStringPrefix = "null";
+    if (HOSTNAME != null) {
+      String hostNameToSplit = "";
+      String[] substrs = HOSTNAME.split("\\d+");
+      if (substrs.length > 0) {
+        hostNameToSplit = substrs[0];
+      }
+      int dashIndex = hostNameToSplit.lastIndexOf('-');
+      hostNameStringPrefix = dashIndex == -1 ? hostNameToSplit : hostNameToSplit.substring(0, dashIndex);
+    }
+    return hostNameStringPrefix;
+  }
+
   public static Path getPath(String filePathStr) {
     return defaultFileSystem.getPath(filePathStr);
   }