Updated.

README.md

@@ -2,6 +2,116 @@
 
 [Fluentd](https://fluentd.org/) HTTP input plugin for Protocol Buffers.
 
+## Features
+
+* **ProtoBuf Schemas**: Automatic compilation of `.proto` files located in `proto_dir`
+* **Incoming Message Format**: Support for binary or JSON format (`Content-Type`: `application/octet-stream` or `application/json`)
+* **Outgoing Message Format**: Support for binary or JSON format
+* **Message Types**: Single or Batch
+
+## Schemas (`.proto` files)
+
+The logging of events is assumed to be the prime use-case for this plugin.  
+So, use self-contained `.proto` file(s) that don't import other custom `.proto` file(s).  
+The `package` and `message` names must be distinct and are treated as case-sensitive.
+
+Consider this `log.proto` schema:
+```
+syntax = "proto3";
+
+package service.logging;
+
+import "google/protobuf/timestamp.proto";
+
+message Log {
+  message Context {
+    google.protobuf.Timestamp timestamp = 1;
+    string host_or_ip = 2;
+    string service_name = 3;
+    string user = 4;
+  }
+
+  enum Level {
+    DEBUG = 0;
+    INFO = 1;
+    WARN = 2;
+    ERROR = 3;
+    FATAL = 4;
+  }
+
+  Context context = 1;
+  Level level = 2;
+  string message = 3;
+}
+```
+
+The fully-qualified message type for `Log` will be `service.logging.Log`.  
+This message type is used as the value of `msgtype` query parameter in the URL.  
+See URL section below for more on `msgtype`.
+
+### Single Message
+
+The above schema will be used as-is for the single message.
+
+### Batch Message
+
+For a batch, the schema must be like this:
+```
+message Batch {
+  string type = 1;
+  repeated Log batch = 2;
+}
+```
+
+IMPORTANT:
+The `Batch` message type is part of `log.proto`, it's not a separate file!  
+You can choose any name for a batch message type.
+
+The complete `log.proto` will be:
+```
+syntax = "proto3";
+
+package service.logging;
+
+import "google/protobuf/timestamp.proto";
+
+message Log {
+  message Context {
+    google.protobuf.Timestamp timestamp = 1;
+    string host_or_ip = 2;
+    string service_name = 3;
+    string user = 4;
+  }
+
+  enum Level {
+    DEBUG = 0;
+    INFO = 1;
+    WARN = 2;
+    ERROR = 3;
+    FATAL = 4;
+  }
+
+  Context context = 1;
+  Level level = 2;
+  string message = 3;
+}
+
+message Batch {
+  string type = 1;
+  repeated Log batch = 2;
+}
+```
+
+For batch processing, the plugin looks for special members `type` and `batch`.  
+The `type` will indicate the message type of `batch` i.e. `Log` in this example.
+
+The type of `Batch` is `service.logging.Batch` and it will be the value of `msgtype` in the URL query.  
+The type of `batch` array is `service.logging.Log` and it will be the value of `type`.
+
+The `google.protobuf.Any` type has not been used deliberately here.  
+It stores message type information with each message resulting in increase in size.  
+With the above approach, the type is stored only once for the whole batch.
+
 ## Installation
 
 ### RubyGems
@@ -54,8 +164,36 @@ $ bundle
 </source>
 ```
 
+### Endpoint (URL)
+
+For single message:
+```
+http://<ip>:<port>/<tag>?msgtype=<fully-qualified-message-type>
+```
+
+For batch message:
+```
+http://<ip>:<port>/<tag>?msgtype=<fully-qualified-message-type-for-batch>&batch=true
+```
+
+Without `batch=true` query parameter, the batch will be treated as a single message.
+
+For example, for a log type `service.logging.Log` and its corresponding batch type `service.logging.Batch`:
+
+Single:
+```
+http://localhost:8080/debug.test?msgtype=service.logging.Log
+```
+
+Batch:
+```
+http://localhost:8080/debug.test?msgtype=service.logging.Batch&batch=true
+```
+
+**NOTE**: The values of query parameters (`msgtype`, `batch`) are case-sensitive!
+
 ## Copyright
 
-* Copyright(c) 2020 [Azeem Sajid](https://www.linkedin.com/in/az33msajid/)
+* Copyright&copy; 2020 [Azeem Sajid](https://www.linkedin.com/in/az33msajid/)
 * License
   * Apache License, Version 2.0