pq

protobuf to json deserializer, written in Rust

pq is a tool which deserializes protobuf messages given a set of pre-compiled .fdset files. It can understand varint/leb128-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.

Download

pq is on crates.io: cargo install pq. You can also download a static binary from the releases page.

pq usage

To set up, put your *.fdset files in ~/.pq or /etc/pq or an alternate directory specified with the FDSET_PATH= env var:

$ protoc -o dog.fdset dog.proto
$ protoc -o person.fdset person.proto
$ cp *.fdset ~/.pq/

You can specify additional fdset directories or files via options:

$ pq --msgtype com.example.dog.Dog --fdsetdir ./tests/fdsets <./tests/samples/dog
$ pq --msgtype com.example.dog.Dog --fdsetfile ./tests/fdsets/dog.fdset <./tests/samples/dog

Pipe a single compiled protobuf message:

$ pq --msgtype com.example.dog.Dog <./tests/samples/dog
{
  "age": 4,
  "breed": "poodle",
  "temperament": "excited"
}

Pipe a varint or leb128 delimited stream:

$ pq --msgtype com.example.dog.Dog --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 --beginning --count 1 --msgtype com.example.dog.Dog
{
  "age": 10,
  "breed": "gsd",
  "temperament": "aggressive"
}

Convert a Kafka stream to varint-delimited:

$ pq kafka my_topic --brokers=192.168.0.1:9092 --count 1 --convert varint |\
> pq --msgtype com.example.dog.Dog --stream varint
{
  "age": 10,
  "breed": "gsd",
  "temperament": "aggressive"
}

Compile without kafka

To compile pq without kafka support, run:

$ cargo build --no-default-features