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add "show help" command #505

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Merged
merged 1 commit into from
Jul 14, 2023
Merged

add "show help" command #505

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45 changes: 44 additions & 1 deletion src/admin.rs
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Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
use crate::pool::BanReason;
use crate::stats::pool::PoolStats;
use bytes::{Buf, BufMut, BytesMut};
use log::{error, info, trace};
use log::{debug, error, info, trace};
use nix::sys::signal::{self, Signal};
use nix::unistd::Pid;
use std::collections::HashMap;
Expand Down Expand Up @@ -84,6 +84,10 @@ where
shutdown(stream).await
}
"SHOW" => match query_parts[1].to_ascii_uppercase().as_str() {
"HELP" => {
trace!("SHOW HELP");
show_help(stream).await
}
"BANS" => {
trace!("SHOW BANS");
show_bans(stream).await
Expand Down Expand Up @@ -271,6 +275,45 @@ where
write_all_half(stream, &res).await
}

/// Show all available options.
async fn show_help<T>(stream: &mut T) -> Result<(), Error>
where
T: tokio::io::AsyncWrite + std::marker::Unpin,
{
let mut res = BytesMut::new();

let detail_msg = vec![
"",
"SHOW HELP|CONFIG|DATABASES|POOLS|CLIENTS|SERVERS|USERS|VERSION",
// "SHOW PEERS|PEER_POOLS", // missing PEERS|PEER_POOLS
// "SHOW FDS|SOCKETS|ACTIVE_SOCKETS|LISTS|MEM|STATE", // missing FDS|SOCKETS|ACTIVE_SOCKETS|MEM|STATE
"SHOW LISTS",
// "SHOW DNS_HOSTS|DNS_ZONES", // missing DNS_HOSTS|DNS_ZONES
"SHOW STATS", // missing STATS_TOTALS|STATS_AVERAGES|TOTALS
"SET key = arg",
"RELOAD",
"PAUSE [<db>, <user>]",
"RESUME [<db>, <user>]",
// "DISABLE <db>", // missing
// "ENABLE <db>", // missing
// "RECONNECT [<db>]", missing
// "KILL <db>",
// "SUSPEND",
"SHUTDOWN",
// "WAIT_CLOSE [<db>]", // missing
];

res.put(notify("Console usage", detail_msg.join("\n\t")));
res.put(command_complete("SHOW"));

// ReadyForQuery
res.put_u8(b'Z');
res.put_i32(5);
res.put_u8(b'I');

write_all_half(stream, &res).await
}

/// Show shards and replicas.
async fn show_databases<T>(stream: &mut T) -> Result<(), Error>
where
Expand Down
20 changes: 20 additions & 0 deletions src/messages.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -530,6 +530,26 @@ pub fn command_complete(command: &str) -> BytesMut {
res
}

/// Create a notify message.
pub fn notify(message: &str, details: String) -> BytesMut {
let mut notify_cmd = BytesMut::new();

notify_cmd.put_slice("SNOTICE\0".as_bytes());
notify_cmd.put_slice("C00000\0".as_bytes());
notify_cmd.put_slice(format!("M{}\0", message).as_bytes());
notify_cmd.put_slice(format!("D{}\0", details).as_bytes());

// this extra byte says that is the end of the package
notify_cmd.put_u8(0);

let mut res = BytesMut::new();
res.put_u8(b'N');
res.put_i32(notify_cmd.len() as i32 + 4);
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Subtract one (-1). The length of the message does not include the message identifier (N).

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when chaging to +3, like this:

diff --git a/src/messages.rs b/src/messages.rs
index cb3b595..b1cd3f9 100644
--- a/src/messages.rs
+++ b/src/messages.rs
@@ -541,7 +541,7 @@ pub fn notify(message: &str, details: String) -> BytesMut {
 
     let mut res = BytesMut::new();
     res.put_u8(b'N');
-    res.put_i32(notify_cmd.len() as i32 + 4);
+    res.put_i32(notify_cmd.len() as i32 + 3);
     res.put(notify_cmd);
 
     res

it drops the connection:


❯ PGPASSWORD=postgres psql -h 127.0.0.1 -p 6432 -U postgres pgbouncer -c 'show help';
NOTICE:  Console usage
DETAIL:
	SHOW HELP|CONFIG|DATABASES|POOLS|CLIENTS|SERVERS|USERS|VERSION
	SHOW LISTS
	SHOW STATS
	SET key = arg
	RELOAD
	PAUSE [<db>, <user>]
	RESUME [<db>, <user>]
	SHUTDOWN
message contents do not agree with length in message type "N"
lost synchronization with server: got message type "
connection to server was lost

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From the log:

[2023-07-13T20:43:36.328145Z WARN  pgcat] Client disconnected with error SocketError("Error reading message code from socket - Error Kind(UnexpectedEof)")

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@levkk levkk Jul 13, 2023 •
edited
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Ah nevermind, it must be something else. From the looks of it, your implementation seems correct.

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do you have any idea how to troubleshoot this?

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Ahh! I think there is a missing NULL byte. This is how we format the error message (same format as notice): https://github.com/postgresml/pgcat/blob/main/src/messages.rs#L357-L358

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It worked! 💪

I've rebased and added a better commit message.

Is there anything else that you need me to change?

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looks great!

res.put(notify_cmd);

res
}

pub fn flush() -> BytesMut {
let mut bytes = BytesMut::new();
bytes.put_u8(b'H');
Expand Down