Enabling logging

Below are examples of code that enables logging in different YDB SDKs.

Go (native)

Go (database/sql)

Java

PHP

There are several ways to enable logs in an application that uses ydb-go-sdk:

Using the YDB_LOG_SEVERITY_LEVEL environment variable

This environment variable enables the built-in ydb-go-sdk logger (synchronous, non-block) and prints to the standard output stream.
You can set the environment variable as follows:

export YDB_LOG_SEVERITY_LEVEL=info

(possible values: trace, debug, info, warn, error, fatal, and quiet, defaults to quiet).

Enable a third-party logger go.uber.org/zap

package main

import (
  "context"
  "os"

  "go.uber.org/zap"

  ydbZap "github.com/ydb-platform/ydb-go-sdk-zap"
  "github.com/ydb-platform/ydb-go-sdk/v3"
  "github.com/ydb-platform/ydb-go-sdk/v3/trace"
)

func main() {
  ctx, cancel := context.WithCancel(context.Background())
  defer cancel()
  var log *zap.Logger // zap-logger with init out of this scope
  db, err := ydb.Open(ctx,
    os.Getenv("YDB_CONNECTION_STRING"),
    ydbZap.WithTraces(
      log,
      trace.DetailsAll,
    ),
  )
  if err != nil {
    panic(err)
  }
  defer db.Close(ctx)
  ...
}

Enable a third-party logger github.com/rs/zerolog

package main

import (
  "context"
  "os"

  "github.com/rs/zerolog"

  ydbZerolog "github.com/ydb-platform/ydb-go-sdk-zerolog"
  "github.com/ydb-platform/ydb-go-sdk/v3"
  "github.com/ydb-platform/ydb-go-sdk/v3/trace"
)

func main() {
  ctx, cancel := context.WithCancel(context.Background())
  defer cancel()
  var log zerolog.Logger // zap-logger with init out of this scope
  db, err := ydb.Open(ctx,
    os.Getenv("YDB_CONNECTION_STRING"),
    ydbZerolog.WithTraces(
      &log,
      trace.DetailsAll,
    ),
  )
  if err != nil {
    panic(err)
  }
  defer db.Close(ctx)
  ...
}

Enable a custom logger implementation github.com/ydb-platform/ydb-go-sdk/v3/log.Logger

package main

import (
  "context"
  "os"

  "github.com/ydb-platform/ydb-go-sdk/v3"
  "github.com/ydb-platform/ydb-go-sdk/v3/log"
  "github.com/ydb-platform/ydb-go-sdk/v3/trace"
)

func main() {
  ctx, cancel := context.WithCancel(context.Background())
  defer cancel()
  var logger log.Logger // logger implementation with init out of this scope
  db, err := ydb.Open(ctx,
    os.Getenv("YDB_CONNECTION_STRING"),
    ydb.WithLogger(
      logger,
      trace.DetailsAll,
    ),
  )
  if err != nil {
    panic(err)
  }
  defer db.Close(ctx)
  ...
}

Implement your own logging package

You can implement your own logging package based on the driver events in the github.com/ydb-platform/ydb-go-sdk/v3/trace tracing package. The github.com/ydb-platform/ydb-go-sdk/v3/trace tracing package describes all logged driver events.

There are several ways to enable logs in an application that uses ydb-go-sdk:

Using the YDB_LOG_SEVERITY_LEVEL environment variable

This environment variable enables the built-in ydb-go-sdk logger (synchronous, non-block) and prints to the standard output stream.
You can set the environment variable as follows:

export YDB_LOG_SEVERITY_LEVEL=info

(possible values: trace, debug, info, warn, error, fatal, and quiet, defaults to quiet).

Enable a third-party logger go.uber.org/zap

package main

import (
  "context"
  "database/sql"
  "os"

  "go.uber.org/zap"

  ydbZap "github.com/ydb-platform/ydb-go-sdk-zap"
  "github.com/ydb-platform/ydb-go-sdk/v3"
  "github.com/ydb-platform/ydb-go-sdk/v3/trace"
)

func main() {
  ctx, cancel := context.WithCancel(context.Background())
  defer cancel()
  var log *zap.Logger // zap-logger with init out of this scope
  nativeDriver, err := ydb.Open(ctx,
    os.Getenv("YDB_CONNECTION_STRING"),
    ydbZap.WithTraces(
      log,
      trace.DetailsAll,
    ),
  )
  if err != nil {
    panic(err)
  }
  defer nativeDriver.Close(ctx)

  connector, err := ydb.Connector(nativeDriver)
  if err != nil {
    panic(err)
  }
  defer connector.Close()

  db := sql.OpenDB(connector)
  defer db.Close()
  ...
}

Enable a third-party logger github.com/rs/zerolog

package main

import (
  "context"
  "database/sql"
  "os"

  "github.com/rs/zerolog"

  ydbZerolog "github.com/ydb-platform/ydb-go-sdk-zerolog"
  "github.com/ydb-platform/ydb-go-sdk/v3"
  "github.com/ydb-platform/ydb-go-sdk/v3/trace"
)

func main() {
  ctx, cancel := context.WithCancel(context.Background())
  defer cancel()
  var log zerolog.Logger // zap-logger with init out of this scope
  nativeDriver, err := ydb.Open(ctx,
    os.Getenv("YDB_CONNECTION_STRING"),
    ydbZerolog.WithTraces(
      &log,
      trace.DetailsAll,
    ),
  )
  if err != nil {
    panic(err)
  }
  defer nativeDriver.Close(ctx)

  connector, err := ydb.Connector(nativeDriver)
  if err != nil {
    panic(err)
  }
  defer connector.Close()

  db := sql.OpenDB(connector)
  defer db.Close()
  ...
}

Enable a custom logger implementation github.com/ydb-platform/ydb-go-sdk/v3/log.Logger

package main

import (
  "context"
  "database/sql"
  "os"

  "github.com/ydb-platform/ydb-go-sdk/v3"
  "github.com/ydb-platform/ydb-go-sdk/v3/log"
  "github.com/ydb-platform/ydb-go-sdk/v3/trace"
)

func main() {
  ctx, cancel := context.WithCancel(context.Background())
  defer cancel()
  var logger log.Logger // logger implementation with init out of this scope
  nativeDriver, err := ydb.Open(ctx,
    os.Getenv("YDB_CONNECTION_STRING"),
    ydb.WithLogger(
      logger,
      trace.DetailsAll,
    ),
  )
  if err != nil {
    panic(err)
  }
  defer nativeDriver.Close(ctx)

  connector, err := ydb.Connector(nativeDriver)
  if err != nil {
    panic(err)
  }
  defer connector.Close()

  db := sql.OpenDB(connector)
  defer db.Close()
  ...
}

Implement your own logging package

For logging purposes, the YDB Java SDK uses the slf4j library, which supports multiple logging levels (error, warn, info, debug, trace) for one or many loggers. The current implementation supports the following loggers:

The com.yandex.ydb.core.grpc logger provides information about the internal implementation of the gRPC protocol
The debug level logs all operations run over gRPC, so we recommend using it only for debugging purposes.
The info level is recommended by default
On the debug level, the com.yandex.ydb.table.impl logger enables you to track the internal status of the YDB driver, including session pool health.
On the debug level, the com.yandex.ydb.table.SessionRetryContext logger will inform you of the number of retries, results of executed queries, execution time of specific retries, and the total operation execution time
On the debug level, the com.yandex.ydb.table.Session logger gives you details about the query text, response status, and execution time of specific operations within the session

Enabling and configuration the Java SDK loggers depends on the slf4j-api implementation used.
Here's an example of a log4j2 configuration for the log4j-slf4j-impl library

<Configuration status="WARN">
  <Appenders>
    <Console name="Console" target="SYSTEM_OUT">
      <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
    </Console>
  </Appenders>

  <Loggers>
    <Logger name="io.netty" level="warn" additivity="false">
      <AppenderRef ref="Console"/>
    </Logger>
    <Logger name="io.grpc.netty" level="warn" additivity="false">
      <AppenderRef ref="Console"/>
    </Logger>
    <Logger name="com.yandex.ydb.core.grpc" level="info" additivity="false">
      <AppenderRef ref="Console"/>
    </Logger>
    <Logger name="com.yandex.ydb.table.impl" level="info" additivity="false">
      <AppenderRef ref="Console"/>
    </Logger>
    <Logger name="com.yandex.ydb.table.SessionRetryContext" level="debug" additivity="false">
      <AppenderRef ref="Console"/>
    </Logger>
    <Logger name="com.yandex.ydb.table.Session" level="debug" additivity="false">
      <AppenderRef ref="Console"/>
    </Logger>

    <Root level="debug" >
      <AppenderRef ref="Console"/>
    </Root>
  </Loggers>
</Configuration>

For logging purposes, you need to use a class, that implements \Psr\Log\LoggerInterface.
ydb-php-sdk has build-in loggers in YdbPlatform\Ydb\Logger namespace:

NullLogger - default logger, which writes nothing
SimpleStdLogger($level) - logger, which writes to logs in stderr.

Usage example:

$config = [
  'logger' => new \YdbPlatform\Ydb\Logger\SimpleStdLogger(\YdbPlatform\Ydb\Logger\SimpleStdLogger::INFO)
]
$ydb = new \YdbPlatform\Ydb\Ydb($config);

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