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Handle standard errors in meta protocol parser #85

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90 changes: 88 additions & 2 deletions src/parser/meta_parser.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,10 +1,11 @@
use nom::{
branch::alt,
bytes::streaming::{tag, take, take_while1},
bytes::streaming::{tag, take, take_until, take_while1},
character::streaming::{crlf, space1},
combinator::{map, opt, value},
combinator::{map, map_res, opt, value},
error::ErrorKind::Fail,
multi::many0,
sequence::{preceded, terminated},
IResult, Parser,
};

Expand All @@ -13,12 +14,32 @@ use std::num::NonZero;
use super::{parse_u32, ErrorKind, MetaResponse, MetaValue, Status};
use crate::Error;

fn parse_meta_error(buf: &[u8]) -> IResult<&[u8], MetaResponse> {
let parser = terminated(
alt((
value(ErrorKind::NonexistentCommand, tag(&b"ERROR"[..])),
map_res(
preceded(tag(&b"CLIENT_ERROR "[..]), take_until("\r\n")),
|s| std::str::from_utf8(s).map(|s| ErrorKind::Client(s.to_string())),
),
map_res(
preceded(tag(&b"SERVER_ERROR "[..]), take_until("\r\n")),
|s| std::str::from_utf8(s).map(|s| ErrorKind::Server(s.to_string())),
),
)),
crlf,
);

map(parser, |e| MetaResponse::Status(Status::Error(e))).parse(buf)
}

pub fn parse_meta_get_status(buf: &[u8]) -> IResult<&[u8], MetaResponse> {
alt((
value(MetaResponse::Status(Status::Value), tag(&b"VA "[..])),
value(MetaResponse::Status(Status::Exists), tag(&b"HD"[..])),
value(MetaResponse::Status(Status::NotFound), tag(&b"EN"[..])),
value(MetaResponse::Status(Status::NoOp), tag(&b"MN\r\n"[..])),
parse_meta_error,
))
.parse(buf)
}
Expand All @@ -30,6 +51,7 @@ pub fn parse_meta_set_status(buf: &[u8]) -> IResult<&[u8], MetaResponse> {
value(MetaResponse::Status(Status::Exists), tag(&b"EX"[..])),
value(MetaResponse::Status(Status::NotFound), tag(&b"NF"[..])),
value(MetaResponse::Status(Status::NoOp), tag(&b"MN\r\n"[..])),
parse_meta_error,
))
.parse(buf)
}
Expand All @@ -40,6 +62,7 @@ pub fn parse_meta_delete_status(buf: &[u8]) -> IResult<&[u8], MetaResponse> {
value(MetaResponse::Status(Status::NotFound), tag(&b"NF"[..])),
value(MetaResponse::Status(Status::Exists), tag(&b"EX"[..])),
value(MetaResponse::Status(Status::NoOp), tag(&b"MN\r\n"[..])),
parse_meta_error,
))
.parse(buf)
}
Expand All @@ -52,6 +75,7 @@ pub fn parse_meta_arithmetic_status(buf: &[u8]) -> IResult<&[u8], MetaResponse>
value(MetaResponse::Status(Status::NotStored), tag(&b"NS"[..])),
value(MetaResponse::Status(Status::Exists), tag(&b"EX"[..])),
value(MetaResponse::Status(Status::NoOp), tag(&b"MN\r\n"[..])),
parse_meta_error,
))
.parse(buf)
}
Expand Down Expand Up @@ -196,6 +220,8 @@ fn parse_meta_get_data_value(buf: &[u8]) -> IResult<&[u8], MetaResponse> {
}
// match arm for "MN\r\n" response
MetaResponse::Status(Status::NoOp) => Ok((input, MetaResponse::Status(Status::NoOp))),
// match arm for standard ASCII error responses: ERROR, CLIENT_ERROR, SERVER_ERROR
MetaResponse::Status(Status::Error(_)) => Ok((input, status)),
_ => {
// unexpected response code, should never happen, bail
Err(nom::Err::Error(nom::error::Error::new(
Expand Down Expand Up @@ -234,6 +260,8 @@ fn parse_meta_set_data_value(buf: &[u8]) -> IResult<&[u8], MetaResponse> {
match status {
// match arm for "MN\r\n" response
MetaResponse::Status(Status::NoOp) => Ok((input, MetaResponse::Status(Status::NoOp))),
// match arm for standard ASCII error responses: ERROR, CLIENT_ERROR, SERVER_ERROR
MetaResponse::Status(Status::Error(_)) => Ok((input, status)),
// match arm for "HD", "NS", "EX" & "NF" responses
MetaResponse::Status(s) => process_meta_response_without_data_payload(input, s),
_ => Err(nom::Err::Error(nom::error::Error::new(
Expand Down Expand Up @@ -271,6 +299,8 @@ fn parse_meta_delete_data_value(buf: &[u8]) -> IResult<&[u8], MetaResponse> {
match status {
// match arm for "MN\r\n" response
MetaResponse::Status(Status::NoOp) => Ok((input, MetaResponse::Status(Status::NoOp))),
// match arm for standard ASCII error responses: ERROR, CLIENT_ERROR, SERVER_ERROR
MetaResponse::Status(Status::Error(_)) => Ok((input, status)),
// match arm for "HD", "NF" & "EX" responses
MetaResponse::Status(s) => process_meta_response_without_data_payload(input, s),
_ => Err(nom::Err::Error(nom::error::Error::new(
Expand Down Expand Up @@ -299,6 +329,8 @@ fn parse_meta_arithmetic_data_value(buf: &[u8]) -> IResult<&[u8], MetaResponse>
}
// match arm for "MN\r\n" response
MetaResponse::Status(Status::NoOp) => Ok((input, MetaResponse::Status(Status::NoOp))),
// match arm for standard ASCII error responses: ERROR, CLIENT_ERROR, SERVER_ERROR
MetaResponse::Status(Status::Error(_)) => Ok((input, status)),
// match arm for "HD", "NF" & "EX" responses
MetaResponse::Status(s) => process_meta_response_without_data_payload(input, s),
_ => Err(nom::Err::Error(nom::error::Error::new(
Expand Down Expand Up @@ -988,4 +1020,58 @@ mod tests {
_ => panic!("Expected Response::Data, got something else"),
}
}

#[test]
fn test_parse_meta_get_response_handles_error() {
let response = parse_meta_get_response(b"ERROR\r\n").unwrap().unwrap();

assert_eq!(response.0, 7);
assert_eq!(
response.1,
MetaResponse::Status(Status::Error(ErrorKind::NonexistentCommand))
);
}

#[test]
fn test_parse_meta_set_response_handles_client_error() {
let response = parse_meta_set_response(b"CLIENT_ERROR bad command line format\r\n")
.unwrap()
.unwrap();

assert_eq!(response.0, 38);
assert_eq!(
response.1,
MetaResponse::Status(Status::Error(ErrorKind::Client(
"bad command line format".to_string()
)))
);
}

#[test]
fn test_parse_meta_delete_response_handles_server_error() {
let response = parse_meta_delete_response(b"SERVER_ERROR out of memory\r\n")
.unwrap()
.unwrap();

assert_eq!(response.0, 28);
assert_eq!(
response.1,
MetaResponse::Status(Status::Error(ErrorKind::Server(
"out of memory".to_string()
)))
);
}

#[test]
fn test_parse_meta_arithmetic_response_handles_client_error() {
let response = parse_meta_arithmetic_response(b"CLIENT_ERROR bad flag\r\n")
.unwrap()
.unwrap();

assert_eq!(response.0, 23);
assert_eq!(
response.1,
MetaResponse::Status(Status::Error(ErrorKind::Client("bad flag".to_string())))
);
}
}
56 changes: 50 additions & 6 deletions src/proto/meta_protocol.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
use crate::{AsMemcachedValue, Client, Error, Status};
use crate::{AsMemcachedValue, Client, Error, ErrorKind, Status};

use crate::parser::{
parse_meta_arithmetic_response, parse_meta_delete_response, parse_meta_get_response,
Expand All @@ -10,6 +10,25 @@ use std::future::Future;

use tokio::io::AsyncWriteExt;

type MetaResponseParser = fn(&[u8]) -> Result<Option<(usize, MetaResponse)>, ErrorKind>;

async fn drain_quiet_noop_response(
client: &mut Client,
parser: MetaResponseParser,
) -> Result<(), Error> {
match client.drive_receive(parser).await? {
MetaResponse::Status(Status::NoOp) => Ok(()),
MetaResponse::Status(status) => Err(Status::Error(ErrorKind::Protocol(Some(format!(
"Expected quiet-mode no-op response, got status {status}"
))))
.into()),
MetaResponse::Data(_) => Err(Status::Error(ErrorKind::Protocol(Some(
"Expected quiet-mode no-op response, got data response".to_string(),
)))
.into()),
}
}

/// Trait defining Meta protocol-specific methods for the Client.
pub trait MetaProtocol {
/// Gets the given key with additional metadata.
Expand Down Expand Up @@ -174,7 +193,12 @@ impl MetaProtocol for Client {

self.conn.flush().await?;

match self.drive_receive(parse_meta_get_response).await? {
let response = self.drive_receive(parse_meta_get_response).await?;
if is_quiet && !matches!(response, MetaResponse::Status(Status::NoOp)) {
drain_quiet_noop_response(self, parse_meta_get_response).await?;
}

match response {
MetaResponse::Status(Status::NotFound) => Ok(None),
MetaResponse::Status(Status::NoOp) => Ok(None),
MetaResponse::Status(s) => Err(s.into()),
Expand Down Expand Up @@ -232,7 +256,12 @@ impl MetaProtocol for Client {

self.conn.flush().await?;

match self.drive_receive(parse_meta_set_response).await? {
let response = self.drive_receive(parse_meta_set_response).await?;
if is_quiet && !matches!(response, MetaResponse::Status(Status::NoOp)) {
drain_quiet_noop_response(self, parse_meta_set_response).await?;
}

match response {
MetaResponse::Status(Status::Stored) => Ok(None),
MetaResponse::Status(Status::NoOp) => Ok(None),
MetaResponse::Status(s) => Err(s.into()),
Expand Down Expand Up @@ -269,7 +298,12 @@ impl MetaProtocol for Client {

self.conn.flush().await?;

match self.drive_receive(parse_meta_delete_response).await? {
let response = self.drive_receive(parse_meta_delete_response).await?;
if is_quiet && !matches!(response, MetaResponse::Status(Status::NoOp)) {
drain_quiet_noop_response(self, parse_meta_delete_response).await?;
}

match response {
MetaResponse::Status(Status::Deleted) => Ok(None),
MetaResponse::Status(Status::Exists) => Err(Error::Protocol(Status::Exists)),
MetaResponse::Status(Status::NoOp) => Ok(None),
Expand Down Expand Up @@ -331,7 +365,12 @@ impl MetaProtocol for Client {

self.conn.flush().await?;

match self.drive_receive(parse_meta_arithmetic_response).await? {
let response = self.drive_receive(parse_meta_arithmetic_response).await?;
if is_quiet && !matches!(response, MetaResponse::Status(Status::NoOp)) {
drain_quiet_noop_response(self, parse_meta_arithmetic_response).await?;
}

match response {
MetaResponse::Status(Status::Stored) => Ok(None),
MetaResponse::Status(Status::NoOp) => Ok(None),
MetaResponse::Status(s) => Err(s.into()),
Expand Down Expand Up @@ -392,7 +431,12 @@ impl MetaProtocol for Client {

self.conn.flush().await?;

match self.drive_receive(parse_meta_arithmetic_response).await? {
let response = self.drive_receive(parse_meta_arithmetic_response).await?;
if is_quiet && !matches!(response, MetaResponse::Status(Status::NoOp)) {
drain_quiet_noop_response(self, parse_meta_arithmetic_response).await?;
}

match response {
MetaResponse::Status(Status::Stored) => Ok(None),
MetaResponse::Status(Status::NoOp) => Ok(None),
MetaResponse::Status(s) => Err(s.into()),
Expand Down
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