File Information
Library: Data
Package: Logging
Header: Poco/Data/SQLChannel.h
Description
This Channel implements logging to a SQL database. The channel is dependent on the schema. The DDL for table creation (subject to target DDL dialect dependent modifications) is:
"CREATE TABLE T_POCO_LOG (Source VARCHAR, Name VARCHAR, ProcessId INTEGER, Thread VARCHAR, ThreadId INTEGER, Priority INTEGER, Text VARCHAR, DateTime DATE)"
The table name is configurable through "table" property. Other than DateTime filed name used for optional time-based archiving purposes, currently the field names are not mandated. However, it is recomended to use names as specified above.
To provide as non-intrusive operation as possbile, the log entries are cached and inserted into the target database asynchronously by default. The blocking, however, will occur before the next entry insertion with default timeout of 1 second. The default settings can be overridden (see async, timeout and throw properties for details). If throw property is false, insertion timeouts are ignored, otherwise a TimeoutException is thrown. To force insertion of every entry, set timeout to 0. This setting, however, introduces a risk of long blocking periods in case of remote server communication delays.
Inheritance
Direct Base Classes: Poco::Channel
All Base Classes: Poco::Channel, Poco::Configurable, Poco::RefCountedObject
Member Summary
Member Functions: close, getProperty, log, open, registerChannel, setProperty, wait
Inherited Functions: close, duplicate, getProperty, log, open, referenceCount, release, setProperty
Types Aliases
Ptr
using Ptr = Poco::AutoPtr < SQLChannel >;
Constructors
SQLChannel
SQLChannel();
Creates SQLChannel.
SQLChannel
SQLChannel(
const std::string & connector,
const std::string & connect,
const std::string & name = "-"
);
Creates a SQLChannel with the given connector, connect string, timeout, table and name. The connector must be already registered.
Destructor
~SQLChannel
~SQLChannel();
Member Functions
close
void close();
Closes the SQLChannel.
See also: Poco::Channel::close()
getProperty
std::string getProperty(
const std::string & name
) const;
Returns the value of the property with the given name.
See also: Poco::Channel::getProperty()
log
void log(
const Message & msg
);
Writes the log message to the database.
See also: Poco::Channel::log()
open
void open();
Opens the SQLChannel.
See also: Poco::Channel::open()
registerChannel
static void registerChannel();
Registers the channel with the global LoggingFactory.
setProperty
void setProperty(
const std::string & name,
const std::string & value
);
Sets the property with the given value.
The following properties are supported:
- name: The name used to identify the source of log messages. Defaults to "-".
- connector: The target data storage connector name.
- connect: The target data storage connection string.
- table: Destination log table name. Defaults to "T_POCO_LOG". Table must exist in the target database.
- keep: Max row age for the log table. To disable archiving, set this property to empty string or "forever".
- archive: Archive table name. Defaults to "T_POCO_LOG_ARCHIVE". Table must exist in the target database. To disable archiving, set this property to empty string.
- async: Indicates asynchronous execution. When excuting asynchronously, messages are sent to the target using asyncronous execution. However, prior to the next message being processed and sent to the target, the previous operation must have been either completed or timed out (see timeout and throw properties for details on how abnormal conditos are handled).
- timeout: Timeout (ms) to wait for previous log operation completion. Values "0" and "" mean no timeout. Only valid when logging is asynchronous, otherwise ignored.
- throw: Boolean value indicating whether to throw in case of timeout. Setting this property to false may result in log entries being lost. True values are (case insensitive) "true", "t", "yes", "y". Anything else yields false.
See also: Poco::Channel::setProperty()
wait
std::size_t wait();
Waits for the completion of the previous operation and returns the result. If chanel is in synchronous mode, returns 0 immediately.
Variables
PROP_ARCHIVE_TABLE
static const std::string PROP_ARCHIVE_TABLE;
PROP_ASYNC
static const std::string PROP_ASYNC;
PROP_CONNECT
static const std::string PROP_CONNECT;
PROP_CONNECTOR
static const std::string PROP_CONNECTOR;
PROP_MAX_AGE
static const std::string PROP_MAX_AGE;
PROP_NAME
static const std::string PROP_NAME;
PROP_TABLE
static const std::string PROP_TABLE;
PROP_THROW
static const std::string PROP_THROW;
PROP_TIMEOUT
static const std::string PROP_TIMEOUT;