Fail fast and loud for invalid GELF messages

graylog2-server/src/main/java/org/graylog2/inputs/codecs/GelfCodec.java

@@ -124,6 +124,8 @@ public Message decode(@Nonnull final RawMessage rawMessage) {
             throw new IllegalStateException("JSON is null/could not be parsed (invalid JSON)", e);
         }
 
+        validateGELFMessage(node);
+
         // Timestamp.
         final double messageTimestamp = doubleValue(node, Message.FIELD_TIMESTAMP);
         final DateTime timestamp;
@@ -218,6 +220,33 @@ public Message decode(@Nonnull final RawMessage rawMessage) {
         return message;
     }
 
+    private void validateGELFMessage(JsonNode jsonNode) {
+        final JsonNode hostNode = jsonNode.path("host");
+        if (hostNode.isMissingNode()) {
+            throw new IllegalArgumentException("GELF message is missing mandatory \"host\" field.");
+        }
+        if (!hostNode.isTextual()) {
+            throw new IllegalArgumentException("GELF message has invalid \"host\": " + hostNode.asText());
+        }
+        if (StringUtils.isBlank(hostNode.asText())) {
+            throw new IllegalArgumentException("GELF message has empty mandatory \"host\" field.");
+        }
+        final JsonNode shortMessageNode = jsonNode.path("short_message");
+        if (shortMessageNode.isMissingNode()) {
+            throw new IllegalArgumentException("GELF message is missing mandatory \"short_message\" field.");
+        }
+        if (!shortMessageNode.isTextual()) {
+            throw new IllegalArgumentException("GELF message has invalid \"short_message\": " + shortMessageNode.asText());
+        }
+        if (StringUtils.isBlank(shortMessageNode.asText())) {
+            throw new IllegalArgumentException("GELF message has empty mandatory \"short_message\" field.");
+        }
+        final JsonNode timestampNode = jsonNode.path("timestamp");
+        if (timestampNode.isValueNode() && !timestampNode.isNumber()) {
+            throw new IllegalArgumentException("GELF message has invalid \"timestamp\": " + timestampNode.asText());
+        }
+    }
+
     @Nullable
     @Override
     public CodecAggregator getAggregator() {

graylog2-server/src/test/java/org/graylog2/inputs/codecs/GelfCodecTest.java

@@ -148,4 +148,138 @@ public void decodeLargeCompressedMessageFails() throws Exception {
     public void getAggregatorReturnsGelfChunkAggregator() throws Exception {
         assertThat(codec.getAggregator()).isSameAs(aggregator);
     }
+
+    @Test
+    public void decodeFailsWithoutHost() throws Exception {
+        final String json = "{"
+                + "\"version\": \"1.1\","
+                + "\"short_message\": \"A short message that helps you identify what is going on\""
+                + "}";
+
+        final RawMessage rawMessage = new RawMessage(json.getBytes(StandardCharsets.UTF_8));
+        expectedException.expect(IllegalArgumentException.class);
+        expectedException.expectMessage("GELF message is missing mandatory \"host\" field.");
+
+        codec.decode(rawMessage);
+    }
+
+    @Test
+    public void decodeFailsWithWrongTypeForHost() throws Exception {
+        final String json = "{"
+                + "\"version\": \"1.1\","
+                + "\"host\": 42,"
+                + "\"short_message\": \"A short message that helps you identify what is going on\""
+                + "}";
+
+        final RawMessage rawMessage = new RawMessage(json.getBytes(StandardCharsets.UTF_8));
+        expectedException.expect(IllegalArgumentException.class);
+        expectedException.expectMessage("GELF message has invalid \"host\": 42");
+
+        codec.decode(rawMessage);
+    }
+
+    @Test
+    public void decodeFailsWithEmptyHost() throws Exception {
+        final String json = "{"
+                + "\"version\": \"1.1\","
+                + "\"host\": \"\","
+                + "\"short_message\": \"A short message that helps you identify what is going on\""
+                + "}";
+
+        final RawMessage rawMessage = new RawMessage(json.getBytes(StandardCharsets.UTF_8));
+        expectedException.expect(IllegalArgumentException.class);
+        expectedException.expectMessage("GELF message has empty mandatory \"host\" field.");
+
+        codec.decode(rawMessage);
+    }
+
+    @Test
+    public void decodeFailsWithBlankHost() throws Exception {
+        final String json = "{"
+                + "\"version\": \"1.1\","
+                + "\"host\": \"      \","
+                + "\"short_message\": \"A short message that helps you identify what is going on\""
+                + "}";
+
+        final RawMessage rawMessage = new RawMessage(json.getBytes(StandardCharsets.UTF_8));
+        expectedException.expect(IllegalArgumentException.class);
+        expectedException.expectMessage("GELF message has empty mandatory \"host\" field.");
+
+        codec.decode(rawMessage);
+    }
+
+    @Test
+    public void decodeFailsWithoutShortMessage() throws Exception {
+        final String json = "{"
+                + "\"version\": \"1.1\","
+                + "\"host\": \"example.org\""
+                + "}";
+
+        final RawMessage rawMessage = new RawMessage(json.getBytes(StandardCharsets.UTF_8));
+        expectedException.expect(IllegalArgumentException.class);
+        expectedException.expectMessage("GELF message is missing mandatory \"short_message\" field.");
+
+        codec.decode(rawMessage);
+    }
+
+    @Test
+    public void decodeFailsWithWrongTypeForShortMessage() throws Exception {
+        final String json = "{"
+                + "\"version\": \"1.1\","
+                + "\"host\": \"example.org\","
+                + "\"short_message\": 42"
+                + "}";
+
+        final RawMessage rawMessage = new RawMessage(json.getBytes(StandardCharsets.UTF_8));
+        expectedException.expect(IllegalArgumentException.class);
+        expectedException.expectMessage("GELF message has invalid \"short_message\": 42");
+
+        codec.decode(rawMessage);
+    }
+
+    @Test
+    public void decodeFailsWithEmptyShortMessage() throws Exception {
+        final String json = "{"
+                + "\"version\": \"1.1\","
+                + "\"host\": \"example.org\","
+                + "\"short_message\": \"\""
+                + "}";
+
+        final RawMessage rawMessage = new RawMessage(json.getBytes(StandardCharsets.UTF_8));
+        expectedException.expect(IllegalArgumentException.class);
+        expectedException.expectMessage("GELF message has empty mandatory \"short_message\" field.");
+
+        codec.decode(rawMessage);
+    }
+
+    @Test
+    public void decodeFailsWithBlankShortMessage() throws Exception {
+        final String json = "{"
+                + "\"version\": \"1.1\","
+                + "\"host\": \"example.org\","
+                + "\"short_message\": \"     \""
+                + "}";
+
+        final RawMessage rawMessage = new RawMessage(json.getBytes(StandardCharsets.UTF_8));
+        expectedException.expect(IllegalArgumentException.class);
+        expectedException.expectMessage("GELF message has empty mandatory \"short_message\" field.");
+
+        codec.decode(rawMessage);
+    }
+
+    @Test
+    public void decodeFailsWithWrongTypeForTimestamp() throws Exception {
+        final String json = "{"
+                + "\"version\": \"1.1\","
+                + "\"host\": \"example.org\","
+                + "\"short_message\": \"A short message that helps you identify what is going on\","
+                + "\"timestamp\": \"Foobar\""
+                + "}";
+
+        final RawMessage rawMessage = new RawMessage(json.getBytes(StandardCharsets.UTF_8));
+        expectedException.expect(IllegalArgumentException.class);
+        expectedException.expectMessage("GELF message has invalid \"timestamp\": Foobar");
+
+        codec.decode(rawMessage);
+    }
 }