pq is a tool which deserializes protobuf messages given a set of pre-compiled .fdset files. It can understand varint-delimited streams, and it can connect to Kafka.
pq will pretty-print when outputting to a tty, but you should pipe it to jq for more fully-featured json handling.
pq is on crates.io: cargo install pq. You can also download a static binary from the releases page.
To set up, put your *.fdset files in ~/.pq:
$ protoc -o dog.fdset dog.proto
$ protoc -o person.fdset person.proto
$ cp *.fdset ~/.pq/
Pipe a single compiled protobuf message - pq will guess the type:
$ pq <./tests/samples/dog
{
"age": 4,
"breed": "poodle",
"temperament": "excited"
}
Provide a more explicit message type with --msgtype:
$ pq <./tests/samples/dog --msgtype=com.example.dog.Dog
{
"age": 4,
"breed": "poodle",
"temperament": "excited"
}
Pipe a varint-delimited stream:
$ pq --stream="varint" <./tests/samples/dog_stream
{
"age": 10,
"breed": "gsd",
"temperament": "aggressive"
}
Consume from a Kafka stream:
$ pq kafka my_topic --brokers=192.168.0.1:9092 --from-beginning --count=1
{
"age": 10,
"breed": "gsd",
"temperament": "aggressive"
}
Convert a Kafka stream to varint-delimited:
$ pq kafka my_topic --brokers=192.168.0.1:9092 --beginning --count=1 --convert=varint | pq --stream=varint
{
"age": 10,
"breed": "gsd",
"temperament": "aggressive"
}