more sprintf java impl, relates to #4191

First the case with single fieldref

Add support for +%s => epoch

Small comments concerning the caching mechanism and the memory usage

Make the #sprintf method work with Array and Hash

src/main/java/com/logstash/DateNode.java

@@ -4,6 +4,9 @@ import org.joda.time.DateTimeZone;
 import org.joda.time.format.DateTimeFormat;
 import org.joda.time.format.DateTimeFormatter;
 
+import java.io.IOError;
+import java.io.IOException;
+
 /**
  * Created by ph on 15-05-22.
  */
@@ -15,7 +18,7 @@ public class DateNode implements TemplateNode {
     }
 
     @Override
-    public String evaluate(Event event) {
+    public String evaluate(Event event) throws IOException {
         return event.getTimestamp().getTime().toString(this.formatter);
     }
 }

src/main/java/com/logstash/EpochNode.java

@@ -1,5 +1,7 @@
 package com.logstash;
 
+import java.io.IOException;
+
 /**
  * Created by ph on 15-05-22.
  */
@@ -7,9 +9,7 @@ public class EpochNode implements TemplateNode {
     public EpochNode(){ }
 
     @Override
-    public String evaluate(Event event) {
-        // TODO: Change this for the right call
-        Long epoch = 1L;
-        return String.valueOf(epoch);
+    public String evaluate(Event event) throws IOException {
+        return String.valueOf(event.getTimestamp().getTime().getMillis() / 1000);
     }
 }

src/main/java/com/logstash/Event.java

@@ -42,5 +42,5 @@ public interface Event {
 
     Event append(Event e);
 
-    String sprintf(String s);
+    String sprintf(String s) throws IOException;
 }

src/main/java/com/logstash/EventImpl.java

@@ -133,9 +133,8 @@ public class EventImpl implements Event, Cloneable, Serializable {
     }
 
     @Override
-    public String sprintf(String s) {
-        // TODO: implement sprintf
-        return s;
+    public String sprintf(String s) throws IOException {
+        return StringInterpolation.getInstance().evaluate(this, s);
     }
 
     public Event clone() {

src/main/java/com/logstash/KeyNode.java

@@ -1,5 +1,12 @@
 package com.logstash;
 
+import org.codehaus.jackson.JsonGenerationException;
+import org.codehaus.jackson.map.ObjectMapper;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+
 /**
  * Created by ph on 15-05-22.
  */
@@ -15,11 +22,19 @@ public class KeyNode implements TemplateNode {
      leverage jackson lib to do the actual.
      */
     @Override
-    public String evaluate(Event event) {
+    public String evaluate(Event event) throws IOException {
         Object value = event.getField(this.key);
 
         if (value != null) {
-            return String.valueOf(event.getField(this.key));
+            if (value instanceof List) {
+                return String.join(",", (List) value);
+            } else if (value instanceof Map) {
+                ObjectMapper mapper = new ObjectMapper();
+                return mapper.writeValueAsString((Map<String, Object>)value);
+            } else {
+                return event.getField(this.key).toString();
+            }
+
         } else {
             return "%{" + this.key + "}";
         }

src/main/java/com/logstash/StaticNode.java

@@ -1,5 +1,7 @@
 package com.logstash;
 
+import java.io.IOException;
+
 /**
  * Created by ph on 15-05-22.
  */
@@ -11,7 +13,7 @@ public class StaticNode implements TemplateNode {
     }
 
     @Override
-    public String evaluate(Event event) {
+    public String evaluate(Event event) throws IOException {
         return this.content;
     }
 }

src/main/java/com/logstash/StringInterpolation.java

@@ -1,7 +1,9 @@
 package com.logstash;
 
 
+import java.io.IOException;
 import java.util.Map;
+import java.util.Objects;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -15,11 +17,19 @@ public class StringInterpolation {
     }
 
     private StringInterpolation() {
-        // TODO: this may need some tweaking for the concurrency level to get better memory usage.
+        // TODO:
+        // This may need some tweaking for the concurrency level to get better memory usage.
+        // The current implementation doesn't allow the keys to expire, I think under normal usage
+        // the keys will converge to a fixed number.
+        //
+        // If this code make logstash goes OOM, we have the following options:
+        //  - If the key doesn't contains a `%` do not cache it, this will reduce the key size at a performance cost.
+        //  - Use some kind LRU cache
+        //  - Create a new data structure that use weakref or use Google Guava for the cache https://code.google.com/p/guava-libraries/
         this.cache = new ConcurrentHashMap<>();
     }
 
-    public String evaluate(Event event, String template) {
+    public String evaluate(Event event, String template) throws IOException {
         TemplateNode compiledTemplate = (TemplateNode) this.cache.get(template);
 
         if(compiledTemplate == null) {
@@ -46,11 +56,11 @@ public class StringInterpolation {
             while (matcher.find()) {
                 if (matcher.start() > 0) {
                     compiledTemplate.add(new StaticNode(template.substring(pos, matcher.start())));
-                    pos = matcher.end();
                 }
 
                 tag = matcher.group(1);
                 compiledTemplate.add(identifyTag(tag));
+                pos = matcher.end();
             }
 
             if(pos < template.length() - 1) {
@@ -67,11 +77,12 @@ public class StringInterpolation {
         }
     }
 
-    // TODO: add support for array, hash, float and epoch
     public TemplateNode identifyTag(String tag) {
-        // Doesnt support parsing the float yet
-        if(tag.charAt(0) == '+') {
-            return new DateNode(tag.substring(1));
+        if(tag.equals("+%s")) {
+            return new EpochNode();
+        } else if(tag.charAt(0) == '+') {
+                return new DateNode(tag.substring(1));
+
         } else {
             return new KeyNode(tag);
         }

src/main/java/com/logstash/Template.java

@@ -1,5 +1,6 @@
 package com.logstash;
 
+import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -20,7 +21,7 @@ public class Template implements TemplateNode {
     }
 
     @Override
-    public String evaluate(Event event) {
+    public String evaluate(Event event) throws IOException {
         StringBuffer results = new StringBuffer();
 
         for (int i = 0; i < nodes.size(); i++) {

src/main/java/com/logstash/TemplateNode.java

@@ -0,0 +1,12 @@
+package com.logstash;
+
+import org.codehaus.jackson.JsonGenerationException;
+
+import java.io.IOException;
+
+/**
+ * Created by ph on 15-05-22.
+ */
+public interface TemplateNode {
+    String evaluate(Event event) throws IOException;
+}

src/main/java/com/logstash/ext/JrubyEventExtLibrary.java

@@ -193,8 +193,7 @@ public class JrubyEventExtLibrary implements Library {
         }
 
         @JRubyMethod(name = "sprintf", required = 1)
-        public IRubyObject ruby_sprintf(ThreadContext context, IRubyObject format)
-        {
+        public IRubyObject ruby_sprintf(ThreadContext context, IRubyObject format) throws IOException {
             return RubyString.newString(context.runtime, event.sprintf(format.toString()));
         }
 

src/test/java/com/logstash/StringInterpolationTest.java

@@ -1,8 +1,11 @@
 package com.logstash;
 
 
+import org.joda.time.DateTime;
 import org.junit.Test;
 
+import java.io.IOException;
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -11,7 +14,7 @@ import static org.junit.Assert.*;
 
 public class StringInterpolationTest {
     @Test
-    public void testCompletelyStaticTemplate() {
+    public void testCompletelyStaticTemplate() throws IOException {
         Event event = getTestEvent();
         String path = "/full/path/awesome";
         StringInterpolation si = StringInterpolation.getInstance();
@@ -20,7 +23,7 @@ public class StringInterpolationTest {
     }
 
     @Test
-    public void testOneLevelField() {
+    public void testOneLevelField() throws IOException {
         Event event = getTestEvent();
         String path = "/full/%{bar}/awesome";
         StringInterpolation si = StringInterpolation.getInstance();
@@ -29,7 +32,7 @@ public class StringInterpolationTest {
     }
 
     @Test
-    public void testMultipleLevelField() {
+    public void testMultipleLevelField() throws IOException {
         Event event = getTestEvent();
         String path = "/full/%{bar}/%{awesome}";
         StringInterpolation si = StringInterpolation.getInstance();
@@ -38,7 +41,7 @@ public class StringInterpolationTest {
     }
 
     @Test
-    public void testMissingKey() {
+    public void testMissingKey() throws IOException {
         Event event = getTestEvent();
         String path = "/full/%{do-not-exist}";
         StringInterpolation si = StringInterpolation.getInstance();
@@ -47,7 +50,7 @@ public class StringInterpolationTest {
     }
 
     @Test
-    public void testDateFormater() {
+    public void testDateFormater() throws IOException {
         Event event = getTestEvent();
         String path = "/full/%{+YYYY}";
         StringInterpolation si = StringInterpolation.getInstance();
@@ -56,7 +59,7 @@ public class StringInterpolationTest {
     }
 
     @Test
-    public void TestMixDateAndFields() {
+    public void TestMixDateAndFields() throws IOException {
         Event event = getTestEvent();
         String path = "/full/%{+YYYY}/weeee/%{bar}";
         StringInterpolation si = StringInterpolation.getInstance();
@@ -65,7 +68,7 @@ public class StringInterpolationTest {
     }
 
     @Test
-    public void testUnclosedTag() {
+    public void testUnclosedTag() throws IOException {
         Event event = getTestEvent();
         String path = "/full/%{+YYY/web";
         StringInterpolation si = StringInterpolation.getInstance();
@@ -73,10 +76,65 @@ public class StringInterpolationTest {
         assertEquals("/full/%{+YYY/web", si.evaluate(event, path));
     }
 
+    @Test
+    public void TestStringIsOneDateTag() throws IOException {
+        Event event = getTestEvent();
+        String path = "%{+YYYY}";
+        StringInterpolation si = StringInterpolation.getInstance();
+        assertEquals("2015", si.evaluate(event, path));
+    }
+
+    @Test
+    public void TestFieldRef() throws IOException {
+        Event event = getTestEvent();
+        String path = "%{[j][k1]}";
+        StringInterpolation si = StringInterpolation.getInstance();
+        assertEquals("v", si.evaluate(event, path));
+    }
+
+    @Test
+    public void TestEpoch() throws IOException {
+        Event event = getTestEvent();
+        String path = "%{+%s}";
+        StringInterpolation si = StringInterpolation.getInstance();
+        assertEquals("1443672000", si.evaluate(event, path));
+    }
+
+    @Test
+    public void TestValueIsArray() throws IOException {
+        ArrayList l = new ArrayList();
+        l.add("Hello");
+        l.add("world");
+
+        Event event = getTestEvent();
+        event.setField("message", l);
+
+        String path = "%{message}";
+        StringInterpolation si = StringInterpolation.getInstance();
+        assertEquals("Hello,world", si.evaluate(event, path));
+    }
+
+    @Test
+    public void TestValueIsHash() throws IOException {
+        Event event = getTestEvent();
+
+        String path = "%{j}";
+        StringInterpolation si = StringInterpolation.getInstance();
+        assertEquals("{\"k1\":\"v\"}", si.evaluate(event, path));
+    }
+
     public Event getTestEvent() {
         Map data = new HashMap();
+        Map inner = new HashMap();
+
+        inner.put("k1", "v");
+
         data.put("bar", "foo");
         data.put("awesome", "logstash");
+        data.put("j", inner);
+        data.put("@timestamp", new DateTime(2015, 10, 1, 0, 0, 0));
+
+
         Event event = new EventImpl(data);
 
         return event;