[go: up one dir, main page]

RPC: FIX leak - adaptation in Resto and RPC middleware

Diana Savvatinarequested to merge
diana.savvatina@rpc_leak_fix into master

What

Fixing leak of file descriptors when External RPC process is used, see the doc:

Why

The leak of FDs was caused by 3 bugs:

  1. EOF was not read on the External RPC process as the handler is busy with handling of streamed requests, like /monitor/heads/main
  2. RPC middleware was not notified when a client dies. Missing functionality in Tezos code which is easy to introduce
  3. Cohttp was not closing client-side connection on request in Tezos use case: on relay connections

How

Resto changes:

  • adaptation to close_fn provided by Cohttp
  • providing sleep_fn to Cohttp to get notified on EOF from peer for a client-side connection

RPC middleware:

  • providing a close_conn callback for a client-side connection to be notified on EOF
  • adaptation to close_fn provided by Cohttp

Manually testing the MR

Described in RPC UX: Resto, Cohttp and Lwt_stream usage

In terminal 1:

TEZOS_LOG="*->debug" CONDUIT_TLS=native CONDUIT_DEBUG=true COHTTP_DEBUG=true DATA_DIR=/tmp/lapin ./src/bin_node/octez-sandboxed-node.sh 1 --connections 0  2>&1 | grep -v quota

If you are running it for the first time, stop it, edit file /tmp/lapin/config.json, then start again:

-  "listen-addrs": ["127.0.0.1:18731"]
+  "external-listen-addrs": ["127.0.0.1:18731"]

If you run it multiple times and something weird happens, change the folder /tmp/lalpin to something else. E.g. /tmp/lapin1. When the external RPC process is started, it prints a trace:

starting RPC server on ::ffff:127.0.0.1:18731 (acl = AllowAll)

In terminal 2:

eval `./src/bin_client/octez-init-sandboxed-client.sh 1`
octez-activate-alpha
curl 'localhost:18731/monitor/heads/main'

Curl will wait for the new blocks until it is stopped.

In terminal 3:

lsof -a -U -c main.exe ; lsof -a -i -c main.exe | grep -v -e CLOSE_WAIT -e CLOSED ; lsof -a -i -c curl

Again in terminal 2:

Ctrl+C  // to stop curl

If the test is passed, you will see traces in terminal 1 about EOF, conn_closed() callbacks called by Cohttp, Resto and RPC middleware. Now, if you run lsof again, you will see that the connections created for curl are released in Tezos node and External RPC process.

Checklist

  • Document the interface of any function added or modified (see the coding guidelines)
  • Document any change to the user interface, including configuration parameters (see node configuration)
  • Provide automatic testing (see the testing guide).
  • For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
  • Select suitable reviewers using the Reviewers field below.
  • Select as Assignee the next person who should take action on that MR

Merge request reports