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//! Real v1/v1alpha reflection using generated services and connection-owned stream futures.
use anyhow::{ensure, Result};
use prost::Message;
use prost_reflect::{DescriptorPool, FileDescriptor};
use std::{collections::HashSet, sync::Arc};
const MAX_FILES: usize = 128;
const MAX_QUERIES: usize = 128;
const MAX_REQUEST_BYTES: usize = 64 * 1024;
const MAX_DESCRIPTOR_BYTES: usize = 4 * 1024 * 1024;
// Descriptor bytes plus repeated-field framing and the original request/host echo.
const MAX_RESPONSE_BYTES: usize = 5 * 1024 * 1024;
pub(super) struct Reflection(DescriptorPool);
impl Reflection {
pub fn new(pool: &DescriptorPool) -> Result<Arc<Self>> {
let mut pool = pool.clone();
for bytes in [
tonic_reflection::pb::v1::FILE_DESCRIPTOR_SET,
tonic_reflection::pb::v1alpha::FILE_DESCRIPTOR_SET,
] {
let descriptors = prost_types::FileDescriptorSet::decode(bytes)?;
for file in descriptors.file {
if let Some(existing) = pool.get_file_by_name(file.name()) {
ensure!(
existing.file_descriptor_proto() == &file,
"startup schema replaces a reserved reflection descriptor"
);
} else {
pool.add_file_descriptor_proto(file)?;
}
}
}
ensure!(
pool.files().len() <= MAX_FILES,
"reflection schema exceeds 128 files"
);
let bytes = pool
.file_descriptor_protos()
.map(Message::encoded_len)
.sum::<usize>();
ensure!(
bytes <= MAX_DESCRIPTOR_BYTES,
"reflection schema exceeds 4 MiB"
);
ensure!(
pool.services().len() <= 128,
"reflection schema exceeds 128 services"
);
Ok(Arc::new(Self(pool)))
}
fn file_for_symbol(&self, name: &str) -> Option<FileDescriptor> {
if let Some(message) = self.0.get_message_by_name(name) {
return Some(message.parent_file());
}
if let Some(service) = self.0.get_service_by_name(name) {
return Some(service.parent_file());
}
if let Some(enumeration) = self.0.get_enum_by_name(name) {
return Some(enumeration.parent_file());
}
if let Some(extension) = self.0.get_extension_by_name(name) {
return Some(extension.parent_file());
}
// Protobuf enum values are siblings of their enum in the symbol namespace.
for enumeration in self.0.all_enums() {
if enumeration.values().any(|value| value.full_name() == name) {
return Some(enumeration.parent_file());
}
}
// grpcurl also asks about fully qualified method and field symbols.
let (parent, child) = name.rsplit_once('.')?;
if let Some(service) = self.0.get_service_by_name(parent) {
if service.methods().any(|method| method.name() == child) {
return Some(service.parent_file());
}
}
if let Some(message) = self.0.get_message_by_name(parent) {
if message.get_field_by_name(child).is_some()
|| message.oneofs().any(|oneof| oneof.name() == child)
{
return Some(message.parent_file());
}
}
None
}
fn files(&self, root: FileDescriptor) -> Vec<Vec<u8>> {
let mut seen = HashSet::new();
let mut pending = vec![root];
let mut files = Vec::new();
while let Some(file) = pending.pop() {
if seen.insert(file.name().to_owned()) {
files.push(file.file_descriptor_proto().encode_to_vec());
pending.extend(file.dependencies());
}
}
files
}
}
// Both generated protocols have the same query semantics. The stream itself polls
// the request; there is no spawned library worker to outlive a cancelled response.
macro_rules! reflection_version {
($module:ident, $version:ident) => {
mod $module {
use super::*;
use futures::{Stream, StreamExt};
use hyper::{body::Incoming, Request};
use std::pin::Pin;
use tonic::{codec::CompressionEncoding, Response, Status, Streaming};
use tonic_reflection::pb::$version::{
server_reflection_request::MessageRequest,
server_reflection_response::MessageResponse,
server_reflection_server::{ServerReflection, ServerReflectionServer},
ErrorResponse, ExtensionNumberResponse, FileDescriptorResponse,
ListServiceResponse, ServerReflectionRequest, ServerReflectionResponse,
ServiceResponse,
};
use tower::Service;
struct Handler(Arc<Reflection>, tokio::time::Instant);
type Replies =
Pin<Box<dyn Stream<Item = Result<ServerReflectionResponse, Status>> + Send>>;
#[tonic::async_trait]
impl ServerReflection for Handler {
type ServerReflectionInfoStream = Replies;
async fn server_reflection_info(
&self,
request: tonic::Request<Streaming<ServerReflectionRequest>>,
) -> Result<Response<Replies>, Status> {
let state = self.0.clone();
let deadline = self.1;
let replies = futures::stream::unfold(
(request.into_inner(), 0usize, false),
move |(mut requests, count, finished)| {
let state = state.clone();
async move {
if finished {
return None;
}
let request = match tokio::time::timeout_at(
deadline,
requests.next(),
)
.await
{
Ok(Some(Ok(request))) => request,
Ok(None) => return None,
Ok(Some(Err(error))) => {
return Some((Err(error), (requests, count, true)))
}
Err(_) => {
return Some((
Err(Status::deadline_exceeded(
"reflection deadline exceeded",
)),
(requests, count, true),
))
}
};
if count >= MAX_QUERIES {
return Some((
Err(Status::resource_exhausted(
"reflection exceeds 128 queries",
)),
(requests, count, true),
));
}
let files = |file: Option<FileDescriptor>| {
file.map(|file| {
MessageResponse::FileDescriptorResponse(
FileDescriptorResponse {
file_descriptor_proto: state.files(file),
},
)
})
};
let reply = match &request.message_request {
Some(MessageRequest::FileByFilename(name)) => {
files(state.0.get_file_by_name(name))
}
Some(MessageRequest::FileContainingSymbol(name)) => {
files(state.file_for_symbol(name))
}
Some(MessageRequest::ListServices(_)) => {
Some(MessageResponse::ListServicesResponse(
ListServiceResponse {
service: state
.0
.services()
.map(|service| ServiceResponse {
name: service.full_name().to_owned(),
})
.collect(),
},
))
}
Some(MessageRequest::AllExtensionNumbersOfType(name)) => {
state.0.get_message_by_name(name).and_then(|message| {
let numbers = message
.extensions()
.map(|extension| i32::try_from(extension.number()))
.collect::<Result<Vec<_>, _>>()
.ok()?;
Some(MessageResponse::AllExtensionNumbersResponse(
ExtensionNumberResponse {
base_type_name: name.clone(),
extension_number: numbers,
},
))
})
}
Some(MessageRequest::FileContainingExtension(extension)) => {
files(
state
.0
.get_message_by_name(&extension.containing_type)
.and_then(|message| {
let number =
u32::try_from(extension.extension_number)
.ok()?;
message
.extensions()
.find(|candidate| {
candidate.number() == number
})
.map(|candidate| candidate.parent_file())
}),
)
}
None => None,
}
.unwrap_or_else(|| {
MessageResponse::ErrorResponse(ErrorResponse {
error_code: 5,
error_message: "reflection symbol or file not found".into(),
})
});
let response = ServerReflectionResponse {
valid_host: request.host.clone(),
original_request: Some(request),
message_response: Some(reply),
};
Some((Ok(response), (requests, count + 1, false)))
}
},
);
Ok(Response::new(Box::pin(replies)))
}
}
pub(super) async fn dispatch(
request: Request<Incoming>,
state: Arc<Reflection>,
deadline: tokio::time::Instant,
) -> hyper::Response<tonic::body::BoxBody> {
let mut service = ServerReflectionServer::new(Handler(state, deadline))
.max_decoding_message_size(MAX_REQUEST_BYTES)
.max_encoding_message_size(MAX_RESPONSE_BYTES)
.accept_compressed(CompressionEncoding::Gzip);
match service.call(request).await {
Ok(response) => response,
Err(never) => match never {},
}
}
}
};
}
reflection_version!(v1, v1);
reflection_version!(v1alpha, v1alpha);
pub(super) async fn dispatch(
request: hyper::Request<hyper::body::Incoming>,
state: Arc<Reflection>,
deadline: tokio::time::Instant,
) -> hyper::Response<tonic::body::BoxBody> {
if request.uri().path() == "/grpc.reflection.v1.ServerReflection/ServerReflectionInfo" {
v1::dispatch(request, state, deadline).await
} else {
v1alpha::dispatch(request, state, deadline).await
}
}