Is there a way to set Relay::OPT_CLIENT_TRACKING flag in the Relay\Cluster constructor?

[dorrogeray]

Hi, I have tested the new option Relay::OPT_CLIENT_TRACKING added in 0.10 with the Relay\Cluster class and it seems to be working for the connections created by getting MOVED responses, but not for the initial connection.

<?php

use Relay\Relay;
use Relay\Cluster;

$relayCluster = new Cluster(
    'my-relay-cluster-client',
    [
        'redis-cluster:6374'
    ],
    5,
    5,
    true,
);
$relayCluster->setOption(Relay::OPT_CLIENT_TRACKING, false);

This code will generate a single tracked connection, but any additional connections based on MOVED responses will be correctly untracked, this is how it can look like:

I think this is because the constructor causes the initial connection to be created before user can set the option on the next line.

Is there any way to pass Relay::OPT_CLIENT_TRACKING directly into the Relay\Cluster constructor, perhaps somehow through the $context argument so that it can be reflected even on the initial connection?

[tillkruss]

We don't have these documented in the stubs (which I'll fix), but you should be able to pass these into cluster $context.

@typedef \Relay\ConnectionContext array{
    use-cache: bool,
    client-tracking: bool,
    throw-on-error: bool
    client-invalidations: bool
    reply-literal: bool
    persistent: bool
    prefix: string
    auth: string|array
    stream: array
    max-retries: int
    serializer: int
    compression: int
    compression-level: int
}

[dorrogeray]

Thanks for the quick answer, but it does not seem to make any difference, neither for prefix or for client-tracking.

<?php

use Relay\Cluster;

$relayCluster = new Cluster(
    'my-relay-cluster-client',
    [
        'redis-cluster:6374'
    ],
    5,
    5,
    true,
    null,
    [
        'client-tracking' => false,
        'prefix' => 'prefixA:',
    ]
);

$relayCluster->set('1', '1');
$relayCluster->set('2', '1');
$relayCluster->set('3', '1');
$relayCluster->set('4', '1');
$relayCluster->set('5', '1');
$relayCluster->set('6', '1');

Here is output my php --ri relay:

Relay Support => enabled
Relay Version => 0.10.0
Available cache => 16722752
Available serializers => php, json, igbinary, msgpack
Available compression => lzf, zstd, lz4
Binary UUID => 4fbd238a-2700-46e9-af6a-6ff0c0805e11
Git SHA => 5398a9c250bef6a1c1fce5349e3e8f0ffcf132e5
Allocator => relay-mmap
Build OS => Ubuntu 16.04.7 LTS
Architecture => x86_64
OpenSSL version => OpenSSL 1.1.1p  21 Jun 2022
License state => unknown
License memory cap => 0
License request id =>  
relay.enabled => true
relay.environment => staging
relay.key =>  
relay.maxmemory => 16777216
relay.maxmemory_pct => 95
relay.eviction_policy => noeviction
relay.eviction_sample_keys => 128
relay.initial_readers => 128
relay.invalidation_poll_usec => 5
relay.default_pconnect => 1
relay.max_endpoint_dbs => 2
relay.locks.allocator => mutex
relay.locks.cache => mutex
relay.loglevel => debug
relay.logfile => /var/log/relay.log
relay.session.compression => none
relay.session.compression_level => 0
relay.session.locking_enabled => 0
relay.session.lock_expire => 0
relay.session.lock_wait_time => 0

[michael-grunder]

Interesting, thanks.

I tested this locally and it seems that the context isn't being forwarded to the underlying connections. It does appear to work this way though:

$rc = new Cluster(
    'my-relay-cluster-client', ['localhost:7000'], 5, 5, true, null,
);

$rc->setOption(Relay::OPT_CLIENT_TRACKING, false);
$rc->setOption(Relay::OPT_PREFIX, 'prefixA:');

foreach ([$r, $rc] as $client) {
    $client->set('foo', 'bar');
    $client->get('foo');
    $client->get('foo');
}

If you set those options before the first command, the connection never enables client tracking and reads the keys we expect (twice):

1739557825.251754 [0 127.0.0.1:56466] "HELLO" "3" "AUTH" "(redacted)" "(redacted)" "SETNAME" "relay@default:2125546"
1739557825.251801 [0 127.0.0.1:56466] "CLIENT" "SETINFO" "LIB-NAME" "relay"
1739557825.251814 [0 127.0.0.1:56466] "CLIENT" "SETINFO" "LIB-VER" "0.10.1-dev"
1739557825.252131 [0 127.0.0.1:56466] "INFO"
1739557825.252275 [0 127.0.0.1:56466] "SET" "prefixA:foo" "bar"
1739557825.252383 [0 127.0.0.1:56466] "GET" "prefixA:foo"
1739557825.252477 [0 127.0.0.1:56466] "GET" "prefixA:foo"

We'll make sure to fix forwarding the context array in the next patch release.

[dorrogeray]

With PHP 8.2 and Relay 0.10, even just calling the Relay\Cluster constructor leads to connection being open:

<?php

use Relay\Relay;
use Relay\Cluster;

$rc = new Cluster(
    'my-relay-cluster-client', ['redis-cluster:6374'], 5, 5, true, null,
);

$rc->setOption(Relay::OPT_CLIENT_TRACKING, false);
$rc->setOption(Relay::OPT_PREFIX, 'prefixA:');

Here is the bash script I use to scan for relay connections:

#!/bin/bash
# Usage: ./redis-client-list-v2.sh [seed_host] [seed_port] [name_filter]
##   seed_host   defaults to 127.0.0.1
##   seed_port   defaults to 6379
##   name_filter optional substring filter to match against the client name

# Get parameters (with defaults)
REDIS_HOST=${1:-127.0.0.1}
REDIS_PORT=${2:-6372}
FILTER=${3:-}

# Define fixed column widths for output
NODE_WIDTH=18
NAME_WIDTH=70
TRACKED_WIDTH=10
FLAGS_WIDTH=10

# Print header
header=$(printf "%-${NODE_WIDTH}s %-${NAME_WIDTH}s %-${TRACKED_WIDTH}s %-${FLAGS_WIDTH}s" \
         "Node Address" "Client Name" "Tracked" "Flags")
echo "$header"

# Create a separator line for the header using dashes
dashes_node=$(printf '%*s' "$NODE_WIDTH" '' | tr ' ' '-')
dashes_name=$(printf '%*s' "$NAME_WIDTH" '' | tr ' ' '-')
dashes_tracked=$(printf '%*s' "$TRACKED_WIDTH" '' | tr ' ' '-')
dashes_flags=$(printf '%*s' "$FLAGS_WIDTH" '' | tr ' ' '-')
printf "%-${NODE_WIDTH}s %-${NAME_WIDTH}s %-${TRACKED_WIDTH}s %-${FLAGS_WIDTH}s\n" \
       "$dashes_node" "$dashes_name" "$dashes_tracked" "$dashes_flags"

# Get the list of nodes from the seed node.
# The "cluster nodes" command returns lines whose second field is like "host:port@..."
nodes=$(redis-cli -h "$REDIS_HOST" -p "$REDIS_PORT" cluster nodes | awk '{print $2}' | cut -d'@' -f1)
if [ -z "$nodes" ]; then
    echo "No nodes found in cluster or unable to connect to $REDIS_HOST:$REDIS_PORT"
    exit 1
fi

# Iterate over each node in the cluster.
for node in $nodes; do
    host=$(echo "$node" | cut -d':' -f1)
    port=$(echo "$node" | cut -d':' -f2)

    # Retrieve the client list from the current node.
    clients=$(redis-cli -h "$host" -p "$port" CLIENT LIST)
    if [ -z "$clients" ]; then
        # If no clients (or if connection failed), print a row with placeholders.
        printf "%-${NODE_WIDTH}s %-${NAME_WIDTH}s %-${TRACKED_WIDTH}s %-${FLAGS_WIDTH}s\n" \
               "$node" "<none>" "N/A" "N/A"
        continue
    fi

    # Process each client line.
    while IFS= read -r line; do
        # Extract the "name" field; the field looks like "name=<value>"
        name=$(echo "$line" | grep -oE 'name=[^ ]*' | cut -d'=' -f2)
        # Remove any stray newline/carriage-return characters.
        name=$(echo "$name" | tr -d '\r\n')
        if [ -z "$name" ]; then
            name="<none>"
        fi

        # If a filter is provided, only continue if the name contains the filter substring.
        if [ -n "$FILTER" ] && [[ "$name" != *"$FILTER"* ]]; then
            continue
        fi

        # Extract the flags (the field looks like "flags=<value>") and clean it.
        flags=$(echo "$line" | grep -oE 'flags=[^ ]*' | cut -d'=' -f2)
        flags=$(echo "$flags" | tr -d '\r\n')

        # Determine if the connection is "tracked" (if the flags contain the letter "t").
        if [[ "$flags" == *"t"* ]]; then
            tracked="Yes"
        else
            tracked="No"
        fi

        # Print the formatted row.
        printf "%-${NODE_WIDTH}s %-${NAME_WIDTH}s %-${TRACKED_WIDTH}s %-${FLAGS_WIDTH}s\n" \
               "$node" "$name" "$tracked" "$flags"
    done <<< "$clients"
done

I run it like this: ./redis-client-list-v2.sh localhost 6372 relay

The last argument filters connections by their names.

And this is confirmation from Redis Insight profiler:

I have redis cluster running at ports 6372-6377.

Maybe in your 0.10.1-dev branch the connection creation is lazy and does not trigger automatically after calling the Relay\Cluster constructor and thats why your code snippet works for you? 🤔

[michael-grunder]

Yeah, Relay will connect and enable client tracking on Relay\Cluster::__construct(). You should then be able to disable client tracking at any point and Relay will switch to a different connection without tracking enabled.

We need to update the logic to account for disabling tracking before any connection is made. The fix shouldn't be too difficult.

[dorrogeray]

Thanks for looking into this! 👍

[tillkruss]

@dorrogeray This is fixed in the next release. Probably this week.