Show ignored errors only on debug mode

main/src/main/java/com/ongres/pgio/main/Main.java

@@ -119,6 +119,8 @@ public class Main {
         "Interval in milliseconds to gather stats")
       .withRequiredArg()
       .defaultsTo("3000");
+    parser.acceptsAll(Lists.newArrayList("d", "debug"), 
+        "Show debug messages");
     parser.acceptsAll(Lists.newArrayList("s", "show-system"), 
         "Print read/write data for the whole system");
     parser.acceptsAll(Lists.newArrayList("o", "show-other"), 
@@ -158,6 +160,7 @@ public class Main {
     configHelper.setIf("show-other", configBuilder::withShowOther);
     configHelper.set("group", Main::readGroupConfig, configBuilder::appendProcessGroups);
     configHelper.setIf("prometheus-format", configBuilder::withPrometheusFormat);
+    configHelper.setIf("debug", configBuilder::withDebug);
     
     Config config = configBuilder.build();
     

main/src/main/java/com/ongres/pgio/main/config/Config.java

@@ -37,11 +37,13 @@ public class Config {
   private final boolean showSystem;
   private final boolean showOther;
   private final Optional<ImmutableList<ProcessGroupInfo>> processGroups;
+  private final boolean debug;
 
   private Config(Path dataDir, long interval, Optional<Integer> ppid, 
       boolean prometheusFormat, 
       boolean noPrintHeader, boolean showSystem, boolean showOther,
-      Optional<ImmutableList<ProcessGroupInfo>> processGroups) {
+      Optional<ImmutableList<ProcessGroupInfo>> processGroups,
+      boolean debug) {
     super();
     this.dataDir = dataDir;
     this.interval = interval;
@@ -51,6 +53,7 @@ public class Config {
     this.showSystem = showSystem;
     this.showOther = showOther;
     this.processGroups = processGroups;
+    this.debug = debug;
   }
 
   public Path getDataDir() {
@@ -85,6 +88,10 @@ public class Config {
     return processGroups;
   }
 
+  public boolean isDebug() {
+    return debug;
+  }
+
   public static class Builder {
     private Path dataDir;
     private long interval;
@@ -95,6 +102,7 @@ public class Config {
     private boolean showOther;
     private Optional<ImmutableList<ProcessGroupInfo>> processGroups = 
         Optional.of(DefaultPostgresGroups.GROUPS);
+    private boolean debug;
     
     public Builder withDataDir(Path dataDir) {
       this.dataDir = dataDir;
@@ -146,13 +154,18 @@ public class Config {
       return this;
     }
     
+    public Builder withDebug(boolean debug) {
+      this.debug = debug;
+      return this;
+    }
+    
     public Config build() {
       Preconditions.checkArgument(dataDir != null, 
           "no database directory specified and environment variable PGDATA unset");
       
       return new Config(dataDir, interval, ppid, 
           prometheusFormat, noPrintHeader, showSystem, showOther, 
-          processGroups);
+          processGroups, debug);
     }
   }
 }

main/src/main/java/com/ongres/pgio/main/stats/StatProcessor.java

@@ -163,7 +163,7 @@ public class StatProcessor {
     if (previousStats.isPresent() && previousStats.get().getStats().containsKey(pid)) {
       return Optional.of(previousStats.get().getStats().get(pid).getInfo());
     } else {
-      return logAndEmptyIfException(() -> new ProcessInfoParser(pid).parse(), 
+      return emptyIfException(() -> new ProcessInfoParser(pid).parse(), 
           () -> "Can not parse process info " + pid + ": ");
     }
   }
@@ -171,24 +171,26 @@ public class StatProcessor {
   private Optional<ProcessStat> getPreviousOrParseIo(
       Optional<StatSnapshot> previousStats, ProcessInfo info) {
     if (previousStats.isPresent() && previousStats.get().getStats().containsKey(info.getPid())) {
-      return logAndEmptyIfException(
+      return emptyIfException(
           () -> previousStats.get().getStats().get(info.getPid())
             .next(new ProcessIoParser(info.getPid()).parse()),
           () -> "Can not parse process io " + info.getPid() + ": ");
     } else {
-      return logAndEmptyIfException(
+      return emptyIfException(
           () -> new ProcessStat(info, new ProcessIoParser(info.getPid()).parse()),
           () -> "Can not parse process io " + info.getPid() + ": ");
     }
   }
   
-  private <T> Optional<T> logAndEmptyIfException(
+  private <T> Optional<T> emptyIfException(
       Callable<T> callable, Supplier<String> errorPrefix) {
     try {
       return Optional.of(callable.call());
     } catch (Throwable throwable) {
-      err.println(errorPrefix.get() + throwable.getMessage());
-      throwable.printStackTrace(err);
+      if (config.isDebug()) {
+        err.println(errorPrefix.get() + throwable.getMessage());
+        throwable.printStackTrace(err);
+      }
       return Optional.empty();
     }
   }