Update README.

Author: hnguyensafetrust

README.md

@@ -1,2 +1,25 @@
 # CustomProtobufPluginExample
-Custom Protobuf Plugin Example in Python
+An example about making a custom Protocol Buffers plugin in python with custom options
+
+# What is Protocol Buffers :
+
+https://developers.google.com/protocol-buffers
+
+https://github.com/protocolbuffers/protobuf
+
+# Plugin
+
+We defined an custom option for protocol buffer in custom_options.proto.
+And we use this custom option in our test.proto as an example.
+
+Plugin read the input .proto files and generate an header .h file based on that.
+Header .h file contain information about which fields use custom options in our custom_options.proto.
+
+# Generate plugin
+
+Run 'gen_plugin.sh' to generate our custom plugin
+
+# Use plugin
+
+After plugin has generated.
+Run 'run_plugin.sh' to use plugin.

gen_plugin.sh

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+rm -rf dist
+mkdir dist
+
+protoc --proto_path=. --python_out=. custom_options.proto
+pyinstaller --onefile custom_plugin.py

run.sh

@@ -0,0 +1 @@
+protoc --plugin=protoc-gen-custom=dist/custom_plugin --custom_out=./build test.proto