Handle regex parsing errors in Gsub and Grok Processors

Currently, both Gsub and Grok parse regex strings during
Pipeline creation. Thrown parsing exceptions were leaking out, this
commit wraps those exceptions in ElasticsearchParseExceptions.

core/src/main/java/org/elasticsearch/ingest/processor/GsubProcessor.java

@@ -19,6 +19,7 @@
 
 package org.elasticsearch.ingest.processor;
 
+import org.elasticsearch.ElasticsearchParseException;
 import org.elasticsearch.ingest.core.AbstractProcessor;
 import org.elasticsearch.ingest.core.AbstractProcessorFactory;
 import org.elasticsearch.ingest.core.IngestDocument;
@@ -28,6 +29,9 @@
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+import static org.elasticsearch.ingest.core.ConfigurationUtils.newConfigurationException;
+import static org.elasticsearch.ingest.core.ConfigurationUtils.readStringProperty;
+
 /**
  * Processor that allows to search for patterns in field content and replace them with corresponding string replacement.
  * Support fields of string type only, throws exception if a field is of a different type.
@@ -79,10 +83,15 @@ public String getType() {
     public static final class Factory extends AbstractProcessorFactory<GsubProcessor> {
         @Override
         public GsubProcessor doCreate(String processorTag, Map<String, Object> config) throws Exception {
-            String field = ConfigurationUtils.readStringProperty(TYPE, processorTag, config, "field");
-            String pattern = ConfigurationUtils.readStringProperty(TYPE, processorTag, config, "pattern");
-            String replacement = ConfigurationUtils.readStringProperty(TYPE, processorTag, config, "replacement");
-            Pattern searchPattern = Pattern.compile(pattern);
+            String field = readStringProperty(TYPE, processorTag, config, "field");
+            String pattern = readStringProperty(TYPE, processorTag, config, "pattern");
+            String replacement = readStringProperty(TYPE, processorTag, config, "replacement");
+            Pattern searchPattern;
+            try {
+                searchPattern = Pattern.compile(pattern);
+            } catch (Exception e) {
+                throw newConfigurationException(TYPE, processorTag, "pattern", "Invalid regex pattern. " + e.getMessage());
+            }
             return new GsubProcessor(processorTag, field, searchPattern, replacement);
         }
     }

core/src/test/java/org/elasticsearch/ingest/processor/GsubProcessorFactoryTests.java

@@ -84,4 +84,18 @@ public void testCreateNoReplacementPresent() throws Exception {
             assertThat(e.getMessage(), equalTo("[replacement] required property is missing"));
         }
     }
+
+    public void testCreateInvalidPattern() throws Exception {
+        GsubProcessor.Factory factory = new GsubProcessor.Factory();
+        Map<String, Object> config = new HashMap<>();
+        config.put("field", "field1");
+        config.put("pattern", "[");
+        config.put("replacement", "-");
+        try {
+            factory.create(config);
+            fail("factory create should have failed");
+        } catch(ElasticsearchParseException e) {
+            assertThat(e.getMessage(), equalTo("[pattern] Invalid regex pattern. Unclosed character class near index 0\n[\n^"));
+        }
+    }
 }

modules/ingest-grok/src/main/java/org/elasticsearch/ingest/grok/GrokProcessor.java

@@ -27,6 +27,8 @@
 import java.util.HashMap;
 import java.util.Map;
 
+import static org.elasticsearch.ingest.core.ConfigurationUtils.newConfigurationException;
+
 public final class GrokProcessor extends AbstractProcessor {
 
     public static final String TYPE = "grok";
@@ -82,7 +84,12 @@ public GrokProcessor doCreate(String processorTag, Map<String, Object> config) t
                 patternBank.putAll(customPatternBank);
             }
 
-            Grok grok = new Grok(patternBank, matchPattern);
+            Grok grok;
+            try {
+                grok = new Grok(patternBank, matchPattern);
+            } catch (Exception e) {
+                throw newConfigurationException(TYPE, processorTag, "pattern", "Invalid regex pattern. " + e.getMessage());
+            }
             return new GrokProcessor(processorTag, grok, matchField);
         }
 

modules/ingest-grok/src/test/java/org/elasticsearch/ingest/grok/GrokProcessorFactoryTests.java

@@ -84,4 +84,33 @@ public void testCreateWithCustomPatterns() throws Exception {
         assertThat(processor.getGrok(), notNullValue());
         assertThat(processor.getGrok().match("foo!"), equalTo(true));
     }
+
+    public void testCreateWithInvalidPattern() throws Exception {
+        GrokProcessor.Factory factory = new GrokProcessor.Factory(Collections.emptyMap());
+        Map<String, Object> config = new HashMap<>();
+        config.put("field", "_field");
+        config.put("pattern", "[");
+        try {
+            factory.create(config);
+            fail("should fail");
+        } catch (ElasticsearchParseException e) {
+            assertThat(e.getMessage(), equalTo("[pattern] Invalid regex pattern. premature end of char-class"));
+        }
+
+    }
+
+    public void testCreateWithInvalidPatternDefinition() throws Exception {
+        GrokProcessor.Factory factory = new GrokProcessor.Factory(Collections.emptyMap());
+        Map<String, Object> config = new HashMap<>();
+        config.put("field", "_field");
+        config.put("pattern", "%{MY_PATTERN:name}!");
+        config.put("pattern_definitions", Collections.singletonMap("MY_PATTERN", "["));
+        try {
+            factory.create(config);
+            fail("should fail");
+        } catch (ElasticsearchParseException e) {
+            assertThat(e.getMessage(), equalTo("[pattern] Invalid regex pattern. premature end of char-class"));
+        }
+
+    }
 }