protobuf-codegen

This crate contains protobuf code generator and a protoc-gen-rust protoc plugin.

protoc-gen-rust

protoc-gen-rust implements standard protobuf protoc plugin conventions.

Probably you do not want to use it directly in Rust environment, there are easier to use alternatives:

protoc-rust crate which can be invoked programmatically from build.rs of your project which requires only protoc in $PATH but not protoc-gen-rust.
protobuf-codegen-pure crate which behaves like protoc-rust, but does not depend on protoc binary

(Note protoc can be invoked programmatically with protoc crate)

On OS X Homebrew can be used:

brew install protobuf

On Ubuntu, protobuf-compiler package can be installed:

apt-get install protobuf-compiler

Protobuf is needed only for code generation, rust-protobuf runtime does not use protobuf library.

It can be installed either from source or with cargo install protobuf command.

If you installed it with cargo, it should be

PATH="$HOME/.cargo/bin:$PATH"

protoc --rust_out . foo.proto

This will generate .rs files in current directory.