Logging

The Couchbase C++ SDK allows logging to be configured programmatically. Internally, the SDK uses the spdlog logging library.

Once the logger has been initialized, The default log level is info.

The following log levels are supported (in order of increasing amount of information logged):

off
critical
error
warning
info
debug
trace

The C++ SDK can be configured to send logs to standard output, or to a file. The logger can be initialized and logging level changed like so:

#import <couchbase/logger.hxx>

void
initialize_logger()
{
    // Initialize logging to standard output
    couchbase::logger::initialize_console_logger();

    // Initialize logging to a file
    couchbase::logger::initialize_file_logger("/path/to/file");

    // Set log level
    couchbase::logger::set_level(couchbase::logger::log_level::warn);
}

SDK Telemetry from the Server

In addition to Tracing and other metrics, and client logging, SDK is telemetry is also sent to the Server — available from 8.0, and in new Capella Operational clusters — for ingestion with other Prometheus metrics. Capella Operational exposes these metrics through the UI.

For self-managed Server, collection can be disabled and enabled through the REST API:

curl --user Administrator:password http://172.17.0.2:8091/settings/appTelemetry -d enabled=true

And the Prometheus-format metrics fetched with:

curl --user Administrator:password http://172.17.0.2:8091/metrics

There may be advantages to collecting information this way, but note that metrics are collected per node, and a central Prometheus instance should be set to collect all metrics so that information is not lost in case of a sudden failover.

Also note that if the cluster is behind a load balancer, the collected metrics may not accurately record the actual correct node with which the SDK interacts.