Compile fails with tonic 0.8

[akiradeveloper]

Bug Report

Version

0.8

Platform

5.4.0-104-generic #118-Ubuntu SMP Wed Mar 2 19:02:41 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux

Crates

Description

After upgrading from 0.7 to 0.8, build started to fail with this message.

  --- stdout
  cargo:rerun-if-changed=proto/reflection.proto
  cargo:rerun-if-changed=proto/

  --- stderr
  thread 'main' panicked at '
  Could not find `protoc` installation and this build crate cannot proceed without
  this knowledge. If `protoc` is installed and this crate had trouble finding
  it, you can set the `PROTOC` environment variable with the specific path to your
  installed `protoc` binary.

This seems to me the change https://github.com/hyperium/tonic/pull/1021 makes it require protoc for some reason.

Because my project was ok with tonic 0.7, this is kind of a bug.

[Smurphy000]

I am also experiencing this behavior. To get past it I installed protoc as the error says to get it to work. Would like to know what caused this and if it can be fixed

[o-agassizii]

Related to this, I expect that some people will also be seeing something similar to the following:

error: failed to run custom build command for `tonic-types v0.6.0 (/tonic/tonic-types)`

Caused by:
  process didn't exit successfully: `/tonic/target/debug/build/tonic-types-124bdc186e7641a9/build-script-build` (exit status: 101)
  --- stdout
  Running: "/usr/bin/protoc" "--include_imports" "--include_source_info" "-o" "/tmp/prost-buildaQyv1g/prost-descriptor-set" "-I" "proto/" "proto/status.proto"

  --- stderr
  thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Custom { kind: Other, error: "protoc failed: google/protobuf/any.proto: File not found.\nstatus.proto:19:1: Import \"google/protobuf/any.proto\" was not found or had errors.\nstatus.proto:46:12: \"google.protobuf.Any\" is not defined.\n" }', tonic-types/build.rs:2:71
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
warning: build failed, waiting for other jobs to finish...

In the case of said related error, as per https://stackoverflow.com/a/61368354 it means that one has protoc installed but not the protobuf resource files.

On Ubuntu, if you are installing via the official repos, make sure both are installed:

apt update && apt upgrade -y
apt install -y protobuf-compiler libprotobuf-dev

On Alpine Linux, if you are installing via the official repos, make sure both are installed:

apk add protoc protobuf-dev

Or alternatively, if the version of protobuf in the repositories is too old then you could instead fetch a specific newer version from GitHub releases page of protobuf, and extract it into /usr. This is what we are doing currently in my company for a CI pipeline where we want a specific version of protobuf.

PROTOC_VERSION=3.20.1
PB_REL="https://github.com/protocolbuffers/protobuf/releases"

which zip || apt update && apt upgrade -y && apt install zip -y

curl -sSLO "$PB_REL/download/v$PROTOC_VERSION/protoc-$PROTOC_VERSION-linux-x86_64.zip"

unzip -o protoc-$PROTOC_VERSION-linux-x86_64.zip -d "/usr"

(On an ordinary end-user machine, or on a long living server, or similar, you would not want to extract stuff into /usr like that but in our case we are doing so on an ephemeral Docker container, so to us in that case it does no harm.)

[LucioFranco]

Generating protobuf via prost now requires protoc in the path (or you can pass in a FileDescriptorSet). The related change is here https://github.com/tokio-rs/prost/pull/657. I believe though that tonic didn't get its docs as updated as prost's so I've opened this issue https://github.com/hyperium/tonic/issues/1049 that we can follow up on.

If you need help with how to get CI working you can also take a look at how tonic and prost both do it. I am going to close this issue, please feel free to reopen if you have any more questions.

[hexfusion]

It feels unfortunate and heavy to require protoc as a dep with tools such as buf[1] around with rust support. I have designed my projects to intentionally NOT require protoc as a dep. Now it must be added to support a single proto required for reflection?

[1] https://github.com/bufbuild/buf

[LucioFranco]

@hexfusion protoc has always been a requirement, before it was just included as a binary in the published crate. But thi is a big security issue and was removed. There is support for buf at https://docs.rs/protoc-gen-tonic/0.2.0/protoc_gen_tonic/

[hexfusion]

Thanks for the clarification.