Add ability to ignore logrotate hourly output

SingularityExecutor/src/main/java/com/hubspot/singularity/executor/config/SingularityExecutorConfiguration.java

@@ -123,6 +123,9 @@ public class SingularityExecutorConfiguration extends BaseRunnerConfiguration {
   @JsonProperty
   private String logrotateExtrasDateformat = "%Y%m%d";
 
+  @JsonProperty
+  private boolean ignoreLogrotateOutput = false;
+
   @NotNull
   @JsonProperty
   private LogrotateCompressionSettings logrotateCompressionSettings = LogrotateCompressionSettings.empty();
@@ -360,6 +363,14 @@ public String getLogrotateExtrasDateformat() {
     return logrotateExtrasDateformat;
   }
 
+  public boolean isIgnoreLogrotateOutput() {
+    return ignoreLogrotateOutput;
+  }
+
+  public void setIgnoreLogrotateOutput(boolean ignoreLogrotateOutput) {
+    this.ignoreLogrotateOutput = ignoreLogrotateOutput;
+  }
+
   public int getTailLogLinesToSave() {
     return tailLogLinesToSave;
   }

SingularityExecutor/src/main/java/com/hubspot/singularity/executor/models/LogrotateCronTemplateContext.java

@@ -11,12 +11,14 @@ public class LogrotateCronTemplateContext {
     private final String logrotateCommand;
     private final String logrotateStateFile;
     private final String logrotateConfig;
+    private final String outputRedirect;
 
     public LogrotateCronTemplateContext(SingularityExecutorConfiguration configuration, SingularityExecutorTaskDefinition taskDefinition, SingularityExecutorLogrotateFrequency logrotateFrequency) {
         this.logrotateCommand = configuration.getLogrotateCommand();
         this.logrotateStateFile = taskDefinition.getLogrotateStateFilePath().toString();
         this.logrotateConfig = Paths.get(configuration.getLogrotateHourlyConfDirectory()).resolve(taskDefinition.getTaskId()).toString();
         this.cronSchedule = logrotateFrequency.getCronSchedule().get();
+        this.outputRedirect = configuration.isIgnoreLogrotateOutput() ? "> /dev/null 2>&1" : "";
     }
 
     public String getLogrotateCommand() {
@@ -34,4 +36,8 @@ public String getLogrotateConfig() {
     public String getCronSchedule() {
         return cronSchedule;
     }
+
+    public String getOutputRedirect() {
+        return outputRedirect;
+    }
 }

SingularityExecutor/src/main/resources/logrotate.cron.hbs

@@ -1 +1 @@
-{{{ cronSchedule }}} root {{{ logrotateCommand }}} -f -s {{{ logrotateStateFile }}} {{{ logrotateConfig }}}
+{{{ cronSchedule }}} root {{{ logrotateCommand }}} -f -s {{{ logrotateStateFile }}} {{{ logrotateConfig }}} {{{ outputRedirect }}}