Add TCP keep-alive configuration support

[maherbeg]

Adds support for configuring TCP keep-alive settings for database connections.

Changes

• Add optional tcpKeepalives, tcpTime, tcpInterval, and tcpRetries parameters to
  values.yaml
• Generate [tcp] section in pgdog.toml when any TCP keep-alive parameter is set
• Document TCP keep-alive configuration in README

Configuration Example

tcpKeepalives: true
tcpTime: 7200
tcpInterval: 75
tcpRetries: 9

All parameters are optional and only included in the config when explicitly set.

Example output

helm template test-pgdog . --set tcpKeepalives=true,tcpTime=7200

# Source: pgdog/templates/config.yaml
apiVersion: v1
kind: ConfigMap
metadata:
    name: test-pgdog
data:
    # This is pgdog.toml. You can configure anything here, incl. databases.
    # Note: don't change the port value, since it's pulled from Values.
    pgdog.toml: |
        [general]
        port                      =   6432
        workers                   =   2
        default_pool_size         =   10
        pooler_mode               =   "transaction"
        healthcheck_interval      =   30_000
        idle_healthcheck_interval =   30_000
        idle_healthcheck_delay    =   5_000
        healthcheck_timeout       =   5_000
        rollback_timeout          =   5_000
        load_balancing_strategy   =   "round_robin"
        read_write_strategy       =   "conservative"
        read_write_split          =   "exclude_primary"
        tls_verify                =   "prefer"
        shutdown_timeout          =   60_000
        prepared_statements       =   "extended"
        passthrough_auth          =   "disabled"
        connect_timeout           =   5_000
        connect_attempts          =   1
        connect_attempt_delay     =   0
        checkout_timeout          =   5_000
        dry_run                   =   false
        mirror_queue              =   128
        mirror_exposure           =   1.0
        auth_type                 =   "scram"
        cross_shard_disabled      =   false
        openmetrics_port = 9090
        openmetrics_namespace = "pgdog_"
        server_lifetime = 86400000
        [tcp]
        keepalives = true
        time = 7200

[levkk]

Awesome, thank you!

[levkk]

Actually could you double check the name of the tcp parameters, just to be sure there are no typos 🙇

[maherbeg]

Amazing, thank you! Looking forward to testing this out when the chart version gets bumped!

[levkk]

Should be available now as v0.15.