inspect-protobuf

Inspect the content of messages encoded with google protobuf.

Requirements

• nodejs ^4

Installation

sudo npm install -g @royaltm/inspect-protobuf

Usage

Display help

inspect-protobuf -h

Usage: inspect-protobuf [options] <proto-file> <ProtoMessageName>


Options:

  -V, --version           output the version number
  -j, --json              json output
  -C, --no-color          monochrome inspect output
  -3, --proto-3           use protobufjs parser (proto-3 support)
  -I, --no-ip             do not decode 4 or 16 bytes as ip addresses
  -e, --bytes <encoding>  decode bytes as strings with encoding
  -m, --msgpack           decode bytes with MessagePack
  -b, --json-bytes        decode bytes as JSON strings
  -h, --help              output usage information

Arguments

Pass proto file and message name arguments. If message name is not provided the first message found in proto file will be used.

cat message.bin | inspect-protobuf path/to/file.proto MyMessage

Alternatively set the environment variable INSPECT_PROTOBUF="path/to/file.proto/MyMessage". In this instance you must append the message name as the last path component.

Format options

no colors

cat message.bin | inspect-protobuf -C

use external json inspector

cat message.bin | inspect-protobuf -j | jq .

Protobuf options

Switch to protobufjs module for proto3 and other protobuf features that are not handled by the protocol-buffers module.

cat message.bin | inspect-protobuf -3

Kafkacat

This tool is best served with kafkacat.

export INSPECT_PROTOBUF="path/to/file.proto/MessageName"
kafkacat -C -b BROKER.BOOTSTRAP.NAME -c 20 -t SOME_TOPIC_NAME -o -1 -f '%S %s' | inspect-protobuf

The important part is kafkacat ... -f '%S %s'. It prepends each message with its byte length, so inspect-protobuf can distinguish each message in a message stream.