// ball_fileobserver.h -*-C++-*-
#ifndef INCLUDED_BALL_FILEOBSERVER
#define INCLUDED_BALL_FILEOBSERVER
#include <bsls_ident.h>
BSLS_IDENT("$Id: $")
//@PURPOSE: Provide a thread-safe observer that logs to a file and to 'stdout'.
//
//@CLASSES:
// ball::FileObserver: observer that writes log records to a file and 'stdout'
//
//@SEE_ALSO: ball_record, ball_context, ball_observer, ball_fileobserver2
//
//@DESCRIPTION: This component provides a concrete implementation of the
// 'ball::Observer' protocol, 'ball::FileObserver', for publishing log records
// to 'stdout' and, optionally, to a user-specified file. The following
// inheritance hierarchy diagram shows the classes involved and their methods:
//..
// ,------------------.
// ( ball::FileObserver )
// `------------------'
// | ctor
// | disableFileLogging
// | disableTimeIntervalRotation
// | disableSizeRotation
// | disableStdoutLoggingPrefix
// | disablePublishInLocalTime
// | enableFileLogging
// | enableStdoutLoggingPrefix
// | enablePublishInLocalTime
// | forceRotation
// | rotateOnSize
// | rotateOnTimeInterval
// | setOnFileRotationCallback
// | setStdoutThreshold
// | setLogFormat
// | suppressUniqueFileNameOnRotation
// | getLogFormat
// | isFileLoggingEnabled
// | isStdoutLoggingPrefixEnabled
// | isPublishInLocalTimeEnabled
// | isSuppressUniqueFileNameOnRotation
// | rotationLifetime
// | rotationSize
// | stdoutThreshold
// V
// ,--------------.
// ( ball::Observer )
// `--------------'
// dtor
// publish
// releaseRecords
//..
// A 'ball::FileObserver' object processes the log records received through its
// 'publish' method by writing them to 'stdout' and, if so configured, to a
// user-specified file. The format of published log records is
// user-configurable for both destinations, 'stdout' and file (see {Log Record
// Formatting} below). Although logging to a file is initially disabled
// following construction, the most common use-case for 'ball::FileObserver' is
// to also log to a file, enabled by calling the 'enableFileLogging' method.
// In addition, a file observer may be configured to perform automatic log file
// rotation (see {Log File Rotation} below).
//
///File Observer Configuration Synopsis
///------------------------------------
// 'ball::FileObserver' offers several constructor arguments and manipulators
// that may be used to configure various aspects of a file observer object.
// These are summarized in the following tables along with the accessors that
// can be used to query the current state of the configuration. Further
// details are provided in the following sections and the function-level
// documentation.
//..
// +-----------------------+-----------------------+
// | Aspect | Constructor Arguments |
// +=======================+=======================+
// | Log Record Timestamps | publishInLocalTime |
// +-----------------------+-----------------------+
// | 'stdout' Logging | stdoutThreshold |
// +-----------------------+-----------------------+
//
// +-------------+------------------------------------+
// | Aspect | Related Methods |
// +=============+====================================+
// | Log Record | setLogFormat |
// | Formatting | enableStdoutLoggingPrefix |
// | | disableStdoutLoggingPrefix |
// | | getLogFormat |
// | | isStdoutLoggingPrefixEnabled |
// +-------------+------------------------------------+
// | Log Record | enablePublishInLocalTime |
// | Timestamps | disablePublishInLocalTime |
// | | isPublishInLocalTimeEnabled |
// | | |
// +-------------+------------------------------------+
// | File | enableFileLogging |
// | Logging | disableFileLogging |
// | | isFileLoggingEnabled |
// | | |
// +-------------+------------------------------------+
// | 'stdout' | setStdoutThreshold |
// | Logging | enableStdoutLoggingPrefix |
// | | disableStdoutLoggingPrefix |
// | | stdoutThreshold |
// | | isStdoutLoggingPrefixEnabled |
// +-------------+------------------------------------+
// | Log File | rotateOnSize |
// | Rotation | rotateOnTimeInterval |
// | | disableSizeRotation |
// | | disableTimeIntervalRotation |
// | | setOnFileRotationCallback |
// | | suppressUniqueFileNameOnRotation |
// | | rotationSize |
// | | rotationLifetime |
// | | isSuppressUniqueFileNameOnRotation |
// +-------------+------------------------------------+
//..
// In general, a 'ball::FileObserver' object can be dynamically configured
// throughout its lifetime (in particular, before or after being registered
// with a logger manager). However, note that for 'ball::FileObserver',
// configuration changes that affect how records are logged (e.g.,
// 'enablePublishInLocalTime' and 'disablePublishInLocalTime') impact only
// those records that are published subsequent to making the configuration
// change.
//
///Log Record Formatting
///---------------------
// By default, the output format of published log records, whether written to
// 'stdout' or to a user-specified file, is:
//..
// DATE_TIME PID:THREAD-ID SEVERITY FILE:LINE CATEGORY MESSAGE USER-FIELDS
//..
// where 'DATE' and 'TIME' are of the form 'DDMonYYYY' and 'HH:MM:SS.mmm',
// respectively ('Mon' being the 3-letter abbreviation for the month). For
// example, a log record will have the following appearance when the default
// format is in effect (assuming that no user-defined fields are present):
//..
// 18MAY2005_18:58:12.076 7959:1 WARN ball_fileobserver.t.cpp:404 TEST hello!
//..
// The default format for records published to 'stdout' (only) can be shortened
// by calling 'disableStdoutLoggingPrefix'. This method has the effect of
// reducing the above example message to the following when output to 'stdout':
//..
// WARN ball_fileobserver.t.cpp:404 TEST hello!
//..
// For additional flexibility, the 'setLogFormat' method can be called to
// configure the format of published records. This method takes two arguments:
// the first argument specifies the format of records logged to a file and the
// second applies to records that are logged to 'stdout'. The respective
// formats are specified using 'printf'-style ('%'-prefixed) conversion
// specifications. (See {'ball_recordstringformatter'} for information on how
// format specifications are defined and interpreted.) For example, the
// following statement will force subsequent records to be logged in a format
// that is almost identical to the default long format except that the
// timestamp attribute will be written in ISO 8601 format:
//..
// fileObserver.setLogFormat("\n%I %p:%t %s %f:%l %c %m %u\n",
// "\n%I %p:%t %s %f:%l %c %m %u\n");
//..
// Once a customized format is specified for 'stdout', calling
// 'disableStdoutLoggingPrefix' will switch to the default short format, i.e.,
// "\n%s %f:%l %c %m %u\n". If 'enableStdoutLoggingPrefix' is subsequently
// called, the customized format specified in the most recent call to
// 'setLogFormat' will be reinstated. Note that the observer emits newline
// characters at the beginning and at the end of a log record by default, so
// the user needs to add them explicitly to the format string to preserve this
// behavior.
//
// Note that in the sample long-form message above the timestamp has
// millisecond precision ('18MAY2005_18:58:12.076'). If microsecond precision
// is desired instead, consider using either the '%D' or '%O' format
// specification supported by 'ball_recordstringformatter'.
//
///Log Record Timestamps
///---------------------
// By default, the timestamp attributes of published records are written in UTC
// time (unless 'true' is supplied for the optional 'publishInLocalTime'
// constructor flag). To write timestamps in local time instead, call the
// 'enablePublishInLocalTime' method. Note that the local time offset is
// calculated using the UTC timestamp of each record. To revert to UTC time,
// call the 'disablePublishInLocalTime' method. Whether UTC time or local time
// is in effect can be queried via 'isPublishInLocalTimeEnabled'.
//
///Local Time Offset Calculations
/// - - - - - - - - - - - - - - -
// The calculation of the local time offset adds some overhead to the
// publication of each log record. If this overhead is an issue, it can be
// mitigated by installing a high-performance local-time offset callback for
// 'bdlt::CurrentTime' in 'main'. See {'bsls_systemtime'} for the details of
// installing such a callback and see {'baltzo_localtimeoffsetutil'} for an
// example facility. Note that such callbacks can improve performance for all
// users of 'bdlt::CurrentTime', not just the 'ball' logger.
//
///Log Filename Patterns
///---------------------
// The 'enableFileLogging' method supports the use of '%'-escape sequences to
// specify log filenames. The recognized sequences are as follows:
//..
// %Y - current year (4 digits with leading zeros)
// %M - current month (2 digits with leading zeros)
// %D - current day (2 digits with leading zeros)
// %h - current hour (2 digits with leading zeros)
// %m - current minute (2 digits with leading zeros)
// %s - current second (2 digits with leading zeros)
// %T - current datetime, equivalent to "%Y%M%D_%h%m%s"
// %p - process ID
//..
// The date and time elements of the derived filename are based on the time
// when the log file is created. Furthermore, these elements are based on
// either UTC time or local time depending on the value returned by
// 'isPublishInLocalTimeEnabled'. (See {Log Record Timestamps} for the
// similarity with the treatment of record timestamps.)
//
// For example, a log filename pattern of "task.log.%Y%M%D_%h%m%s" will yield
// the filename 'task.log.20110501_123000' if the file is created on
// 01-May-2011 at 12:30:00 local time (assuming 'enablePublishInLocalTime' was
// called).
//
///Log File Rotation
///-----------------
// A 'ball::FileObserver' may be configured to perform automatic rotation of
// log files based on simple file rotation conditions (or rules).
//
///File Rotation Conditions
/// - - - - - - - - - - - -
// Rotation rules may be established based on the size of the log file (i.e., a
// "rotation-on-size" rule), and a periodic time interval (i.e., a
// "rotation-on-time-interval" rule). These rules are independently enabled by
// the 'rotateOnSize' and 'rotateOnTimeInterval' methods, respectively. If
// both rules are in effect, log file rotation is performed whenever either
// rule applies.
//
///Rotated File Naming
///- - - - - - - - - -
// When a log file is rotated, a new filename is generated using the pattern
// supplied to 'enableFileLogging'. If the file having the new name does not
// exist, the current log file is closed, and the logging continues to the new
// file.
//
// If the file having the new name already exits, then the behavior of the file
// rotation is further controlled by the flag set with
// 'suppressUniqueFileNameOnRotation':
//
//: o 'suppressUniqueFileNameOnRotation(false)' (*default* behavior)
//: The current log filename is renamed by appending a timestamp in the form
//: ".%Y%M%D_%h%m%s" where the timestamp indicates when the file being
//: rotated was last opened (the time of either the last file rotation or the
//: last call to 'enableFileLogging', whichever is most recent). As with the
//: timestamps of logged records, the timestamps appended to log filenames
//: upon rotation will be in UTC time or local time depending on the value
//: returned by 'isPublishInLocalTimeEnabled'.
//:
//: o 'suppressUniqueFileNameOnRotation(true)'
//: The logging continues to the *current* log file, effectively suppressing
//: log filename rotation. This may happen when the log file pattern does
//: not contain %-escape sequences indicating a time period, or the rotation
//: interval is less than the time period encoded by %-escape sequences. In
//: order to rotate log files in this mode, the log file pattern MUST contain
//: %-escape sequences that specify date and (optionally) time. For example,
//: the log filename pattern "app_%Y%M%D.log" will produce a single log file
//: per calendar day (assuming, the rotation on time is enabled and the
//: rotation happens at least once a day).
//
// The two tables below illustrate the names of old and new log files when a
// file rotation occurs. We assume that the log file is rotated on 2011-May-21
// at 12:29:59 local time and that the last rotation occurred at 12:30:00 on
// the previous day. We further assume that 'enablePublishInLocalTime' was
// called, so that all date and time elements are rendered in local time.
//
// The first table shows the name change (if any) of the (old) log file being
// rotated when the flag controlled by 'suppressUniqueFileNameOnRotation'
// is set to 'false':
//..
// Disabled: 'suppressUniqueFileNameOnRotation'
//
// For brevity:
// <TS1> = 20210520_123000
// <TS2> = 20210521_122959 (aka next day, about the same time)
//
// +----------------+-----------------+----------------+----------------------
// | Pattern | Filename Before | Filename After | Rotated Filename
// | | Rotation | Rotation |
// +----------------+-----------------+----------------+----------------------
// | "a.log" | a.log | a.log | a.log.<TS1>
// | "a.log.%T" | a.log.<TS1> | a.log.<TS2> | a.log.<TS1>
// | "a.log.%Y%M" | a.log.202105 | a.log.202105 | a.log.202105.<TS1>
// | "a.log.%Y%M%D" | a.log.20210520 | a.log.20110521 | a.log.20210520
// +----------------+-----------------+----------------+----------------------
//..
// Note that upon rotation a timestamp was appended to the name of the rotated
// file when the log pattern does not contain %-escape sequences indicating a
// time period ("a.log"), or the rotation period (in our case, one day) is less
// than the time period encoded in the pattern (in case of "a.log.%Y%M" the
// period is one month).
//
// The next table shows the rotated name when the flag controlled by
// 'suppressUniqueFileNameOnRotation' is set to 'true', and (possibly new) name
// of the (new) log file following rotation:
//..
// Enabled: 'suppressUniqueFileNameOnRotation'
//
// +----------------+-----------------+----------------+----------------------
// | Pattern | Filename Before | Filename After | Rotated Filename
// | | Rotation | Rotation |
// +----------------+-----------------+----------------+----------------------
// | "a.log" | a.log | a.log | none
// | "a.log.%T" | a.log.<TS1> | a.log.<TS2> | a.log.<TS1>
// | "a.log.%Y%M" | a.log.202105 | a.log.202105 | none
// | "a.log.%Y%M%D" | a.log.20210520 | a.log.20110521 | a.log.20210520
// +----------------+-----------------+----------------+----------------------
//..
// Note that the original filename is reused when the log pattern does not
// contain %-escape sequences indicating a time period ("a.log"), or the
// rotation period (in our case, one day) is less than the time period encoded
// in the pattern (in case of "a.log.%Y%M" the period is one month).
//
// Also note, that in any cases, when the log pattern includes "%T", or encodes
// a time period that coincides the rotation period (in case of "a.log.%Y%M%D"
// the period is one day), then a unique name on each rotation is produced with
// the (local) time at which file rotation occurred embedded in the filename.
//
///Thread Safety
///-------------
// All methods of 'ball::FileObserver' are thread-safe, and can be called
// concurrently by multiple threads.
//
///Usage
///-----
// This section illustrates intended use of this component.
//
///Example: Basic Usage
/// - - - - - - - - - -
// First, we create a 'ball::LoggerManagerConfiguration' object, 'lmConfig',
// and set the logging "pass-through" level -- the level at which log records
// are published to registered observers -- to 'DEBUG':
//..
// int main()
// {
// ball::LoggerManagerConfiguration lmConfig;
// lmConfig.setDefaultThresholdLevelsIfValid(ball::Severity::e_DEBUG);
//..
// Next, create a 'ball::LoggerManagerScopedGuard' object whose constructor
// takes the configuration object just created. The guard will initialize the
// logger manager singleton on creation and destroy the singleton upon
// destruction. This guarantees that any resources used by the logger manager
// will be properly released when they are not needed:
//..
// ball::LoggerManagerScopedGuard guard(lmConfig);
// ball::LoggerManager& manager = ball::LoggerManager::singleton();
//..
// Next, we create a 'ball::FileObserver' object and register it with the
// 'ball' logging system;
//..
// bsl::shared_ptr<ball::FileObserver> observer =
// bsl::make_shared<ball::FileObserver>();
// int rc = manager.registerObserver(observer, "default");
// ASSERT(0 == rc);
//..
// The default format for outputting log records can be changed by calling the
// 'setLogFormat' method. The statement below outputs record timestamps in ISO
// 8601 format to the log file and in 'bdlt'-style (default) format to
// 'stdout', where timestamps are output with millisecond precision in both
// cases:
//..
// observer->setLogFormat("%I %p:%t %s %f:%l %c %m\n",
// "%d %p:%t %s %f:%l %c %m\n");
//..
// Note that both of the above format specifications omit user fields ('%u') in
// the output. Also note that, unlike the default, this format does not emit a
// blank line between consecutive log messages.
//
// Henceforth, all messages that are published by the logging system will be
// transmitted to the 'publish' method of 'observer'. By default, only the
// messages with a 'e_WARN', 'e_ERROR', or 'e_FATAL' severity will be logged to
// 'stdout':
//..
// BALL_LOG_SET_CATEGORY("main")
// BALL_LOG_INFO << "Will not be published on 'stdout'.";
// BALL_LOG_WARN << "This warning *will* be published on 'stdout'.";
//..
// This default can be changed by specifying an optional argument to the
// 'ball::FileObserver' constructor or by calling the 'setStdoutThreshold'
// method:
//..
// observer->setStdoutThreshold(ball::Severity::e_INFO);
//
// BALL_LOG_DEBUG << "This debug message is not published on 'stdout'.";
// BALL_LOG_INFO << "This info message *will* be published on 'stdout'.";
// BALL_LOG_WARN << "This warning will be published on 'stdout'.";
//..
// The user can log all messages to a specified file and specify rotation rules
// based on the size of the log file or its lifetime:
//..
// // Create and log records to a file named "/var/log/task/task.log".
// observer->enableFileLogging("/var/log/task/task.log");
//
// // Disable 'stdout' logging.
// observer->setStdoutThreshold(ball::Severity::e_OFF);
//
// // Rotate the file when its size becomes greater than or equal to 256
// // megabytes.
// observer->rotateOnSize(1024 * 256);
//
// // Rotate the file every 24 hours.
// observer->rotateOnTimeInterval(bdlt::DatetimeInterval(1));
//..
// Note that in this configuration the user may end up with multiple log files
// for any given day (because of the rotation-on-size rule). This feature can
// be disabled dynamically later:
//..
// observer->disableSizeRotation();
// return 0;
// }
//..
#include <balscm_version.h>
#include <ball_fileobserver2.h>
#include <ball_observer.h>
#include <ball_recordstringformatter.h>
#include <ball_severity.h>
#include <bdlt_datetimeinterval.h>
#include <bslma_allocator.h>
#include <bslma_usesbslmaallocator.h>
#include <bslmf_nestedtraitdeclaration.h>
#include <bslmt_mutex.h>
#include <bsls_libraryfeatures.h>
#include <bsl_memory.h>
#include <bsl_string.h>
#ifdef BSLS_LIBRARYFEATURES_HAS_CPP17_PMR
#include <memory_resource> // 'std::pmr::polymorphic_allocator'
#endif // BSLS_LIBRARYFEATURES_HAS_CPP17_PMR
#include <string> // 'std::string', 'std::pmr::string'
namespace BloombergLP {
namespace ball {
class Context;
class Record;
// ==================
// class FileObserver
// ==================
class FileObserver : public Observer {
// This class implements the 'Observer' protocol. The 'publish' method of
// this class outputs the log records that it receives to 'stdout' and
// optionally to a user-specified file. This class is thread-safe;
// different threads can operate on an object concurrently. This class is
// exception-neutral with no guarantee of rollback. In no event is memory
// leaked.
// DATA
RecordStringFormatter d_logFileFormatter; // record formatter used when
// logging to a file
RecordStringFormatter d_stdoutFormatter; // record formatter used when
// logging to 'stdout'
Severity::Level d_stdoutThreshold; // minimum severity for records
// logged to 'stdout'
bool d_useRegularFormatOnStdoutFlag;
// 'true' if records published
// to 'stdout' in regular
// (long) format, otherwise
// short format is used
bool d_publishInLocalTime; // 'true' if timestamps of
// records are output in local
// time, otherwise UTC time
bool d_userFieldsLoggingFlag;
// 'true' if user-defined
// fields published
// (!DEPRECATED!)
bsl::string d_stdoutLongFormat; // initially set to default
// long format for records
// printed to 'stdout'; updated
// by 'setLogFormat'
bsl::string d_stdoutShortFormat; // default short format for
// records printed to 'stdout'
mutable bslmt::Mutex d_mutex; // serialize operations
FileObserver2 d_fileObserver2; // forward most operations to
// this object
private:
// NOT IMPLEMENTED
FileObserver(const FileObserver&);
FileObserver& operator=(const FileObserver&);
public:
// TYPES
typedef FileObserver2::OnFileRotationCallback OnFileRotationCallback;
// 'OnFileRotationCallback' is an alias for a user-supplied callback
// function that is invoked after the file observer attempts to rotate
// its log file. The callback takes two arguments: (1) an integer
// status value where 0 indicates a new log file was successfully
// created and a non-zero value indicates an error occurred during
// rotation, and (2) a string that provides the name of the rotated log
// file if the rotation was successful. E.g.:
//..
// void onLogFileRotation(int rotationStatus,
// const bsl::string& rotatedLogFileName);
//..
// TRAITS
BSLMF_NESTED_TRAIT_DECLARATION(FileObserver, bslma::UsesBslmaAllocator);
// CREATORS
FileObserver();
explicit FileObserver(bslma::Allocator *basicAllocator);
explicit FileObserver(Severity::Level stdoutThreshold,
bslma::Allocator *basicAllocator = 0);
// Create a file observer that publishes log records to 'stdout' if
// their severity is at least as severe as the optionally specified
// 'stdoutThreshold' level, and has file logging initially disabled.
// If 'stdoutThreshold' is not specified, log records are published to
// 'stdout' if their severity is at least as severe as
// 'Severity::e_WARN'. Optionally specify a 'basicAllocator' used to
// supply memory. If 'basicAllocator' is 0, the currently installed
// default allocator is used. Note that 'isPublishInLocalTimeEnabled'
// returns 'false' following construction indicating that the timestamp
// attribute of published records will be written in UTC time (see
// 'enablePublishInLocalTime'). Also note that independent default
// record formats are in effect for 'stdout' and file logging (see
// 'setLogFormat').
FileObserver(Severity::Level stdoutThreshold,
bool publishInLocalTime,
bslma::Allocator *basicAllocator = 0);
// Create a file observer that publishes log records to 'stdout' if
// their severity is at least as severe as the specified
// 'stdoutThreshold' level, and has file logging initially disabled.
// The timestamp attribute of published records is written in local
// time if the specified 'publishInLocalTime' flag is 'true', and in
// UTC time otherwise. Optionally specify a 'basicAllocator' used to
// supply memory. If 'basicAllocator' is 0, the currently installed
// default allocator is used. Note that following construction
// independent default record formats are in effect for 'stdout' and
// file logging (see 'setLogFormat').
~FileObserver();
// Close the log file of this file observer if file logging is enabled,
// and destroy this file observer.
// MANIPULATORS
void disableFileLogging();
// Disable file logging for this file observer. This method has no
// effect if file logging is not enabled. Note that records
// subsequently received through the 'publish' method of this file
// observer may still be logged to 'stdout' after calling this method.
void disableLifetimeRotation();
// Disable log file rotation based on a periodic time interval for this
// file observer. This method has no effect if
// rotation-on-time-interval is not enabled.
//
// !DEPRECATED!: Use 'disableTimeIntervalRotation' instead.
void disableTimeIntervalRotation();
// Disable log file rotation based on a periodic time interval for this
// file observer. This method has no effect if
// rotation-on-time-interval is not enabled.
void disableSizeRotation();
// Disable log file rotation based on log file size for this file
// observer. This method has no effect if rotation-on-size is not
// enabled.
void disableStdoutLoggingPrefix();
// Disable this file observer from using the long output format when
// logging to 'stdout'. Henceforth, this file observer will use the
// default short output format ("\n%s %f:%l %c %m %u\n") when logging
// to 'stdout'. This method has no effect if the long output format
// for 'stdout' logging is not enabled. Note that this method omits
// the "%d %p:%t " prefix from the default long output format.
void disableUserFieldsLogging();
// Disable the logging of user-defined fields by this file observer.
// This method has no effect if logging of user-defined fields is not
// enabled, or if a format string other than the default one is in
// effect.
//
// !DEPRECATED!: Use 'setLogFormat' instead.
void disablePublishInLocalTime();
// Disable publishing of the timestamp attribute of records in local
// time by this file observer; henceforth, timestamps will be in UTC
// time. This method has no effect if publishing in local time is not
// enabled. Note that this method also affects log filenames (see {Log
// Filename Patterns}).
int enableFileLogging(const char *logFilenamePattern);
// Enable logging of all records published to this file observer to a
// file whose name is derived from the specified 'logFilenamePattern'.
// Return 0 on success, a positive value if file logging is already
// enabled (with no effect), and a negative value otherwise. The
// basename of 'logFilenamePattern' may contain '%'-escape sequences
// that are interpreted as follows:
//..
// %Y - current year (4 digits with leading zeros)
// %M - current month (2 digits with leading zeros)
// %D - current day (2 digits with leading zeros)
// %h - current hour (2 digits with leading zeros)
// %m - current minute (2 digits with leading zeros)
// %s - current second (2 digits with leading zeros)
// %T - current datetime, equivalent to "%Y%M%D_%h%m%s"
// %p - process ID
//..
// Each time a log file is opened by this file observer (upon a
// successful call to this method and following each log file
// rotation), the name of the new log file is derived from
// 'logFilenamePattern' by interpreting the above recognized '%'-escape
// sequences. If 'isPublishInLocalTimeEnabled' returns 'true', the
// '%'-escape sequences related to time will be substituted with local
// time values, and UTC time values otherwise. See {Log Filename
// Patterns}.
int enableFileLogging(const char *logFilenamePattern,
bool appendTimestampFlag);
// Enable logging of all records published to this file observer to a
// file whose name is derived from the specified 'logFilenamePattern'
// and append a timestamp to the log filename if the specified
// 'appendTimestampFlag' is 'true'. Return 0 on success, a positive
// value if file logging is already enabled (with no effect), and a
// negative value otherwise. If the 'appendTimestampFlag' is 'true'
// and 'logFilenamePattern' does not contain any '%'-escape sequences,
// this method behaves as if ".%T" is appended to 'logFilenamePattern'.
//
// !DEPRECATED!: Use 'enableFileLogging(logFilenamePattern)' instead
// (use the ".%T" pattern to replicate 'true == appendTimestampFlag'
// behavior).
void enableStdoutLoggingPrefix();
// Enable this file observer to use the long output format when logging
// to 'stdout'. Henceforth, this file observer will use the output
// format for 'stdout' logging that was set by the most recent call to
// 'setLogFormat', or the default long output format
// ("\n%d %p:%t %s %f:%l %c %m %u\n") if 'setLogFormat' has not yet
// been called. This method has no effect if the long output format
// for 'stdout' logging is already enabled.
void enableUserFieldsLogging();
// Enable the logging of user-defined fields by this file observer.
// This method has no effect if logging of user-defined fields is
// already enabled, or if a format string other than the default one is
// in effect.
//
// !DEPRECATED!: Use 'setLogFormat' instead.
void enablePublishInLocalTime();
// Enable publishing of the timestamp attribute of records in local
// time by this file observer. This method has no effect if publishing
// in local time is already enabled. Note that this method also
// affects log filenames (see {Log Filename Patterns}).
void publish(const Record& record, const Context& context);
// Process the specified log 'record' having the specified publishing
// 'context' by writing 'record' and 'context' to the current log file
// if file logging is enabled for this file observer, and to 'stdout'
// if the severity of 'record' is at least as severe as the value
// returned by 'stdoutThreshold'.
void publish(const bsl::shared_ptr<const Record>& record,
const Context& context);
// Process the record referenced by the specified 'record' shared
// pointer having the specified publishing 'context' by writing the
// record and 'context' to the current log file if file logging is
// enabled for this file observer, and to 'stdout' if the severity of
// 'record' is at least as severe as the value returned by
// 'stdoutThreshold'.
void releaseRecords();
// Discard any shared references to 'Record' objects that were supplied
// to the 'publish' method, and are held by this observer. Note that
// this operation should be called if resources underlying the
// previously provided shared pointers must be released.
void forceRotation();
// Forcefully perform a log file rotation by this file observer. Close
// the current log file, rename the log file if necessary, and open a
// new log file. This method has no effect if file logging is not
// enabled. See {Rotated File Naming} for details on filenames of
// rotated log files.
void rotateOnLifetime(const bdlt::DatetimeInterval& timeInterval);
// Set this file observer to perform a periodic log file rotation at
// multiples of the specified 'timeInterval'. The behavior is
// undefined unless '0 < timeInterval.totalMilliseconds()'. This rule
// replaces any rotation-on-time-interval rule currently in effect.
//
// !DEPRECATED!: Use 'rotateOnTimeInterval' instead.
void rotateOnSize(int size);
// Set this file observer to perform log file rotation when the size of
// the file exceeds the specified 'size' (in kilobytes). This rule
// replaces any rotation-on-size rule currently in effect. The
// behavior is undefined unless 'size > 0'.
void rotateOnTimeInterval(const bdlt::DatetimeInterval& interval);
void rotateOnTimeInterval(const bdlt::DatetimeInterval& interval,
const bdlt::Datetime& startTime);
// Set this file observer to perform a periodic log file rotation at
// multiples of the specified 'interval'. Optionally specify a
// 'startTime' indicating the datetime to use as the starting point for
// computing the periodic rotation schedule. If
// 'isPublishInLocalTimeEnabled' is 'true', the 'startTime' is
// interpreted as local time, and as a UTC time otherwise. If
// 'startTime' is not specified, the current time is used. This rule
// replaces any rotation-on-time-interval rule currently in effect.
// The behavior is undefined unless '0 < interval.totalMilliseconds()'.
// Note that 'startTime' may be a fixed time in the past; e.g., a
// reference time of 'bdlt::Datetime(1, 1, 1)' and an interval of 24
// hours would configure a periodic rotation at midnight each day.
void setOnFileRotationCallback(
const OnFileRotationCallback& onRotationCallback);
// Set the specified 'onRotationCallback' to be invoked after each time
// this file observer attempts to perform a log file rotation. The
// behavior is undefined if the supplied function calls either
// 'setOnFileRotationCallback', 'forceRotation', or 'publish' on this
// file observer (i.e., the supplied callback should *not* attempt to
// write to the 'ball' log).
void setStdoutThreshold(Severity::Level stdoutThreshold);
// Set the minimum severity of records logged to 'stdout' by this file
// observer to the specified 'stdoutThreshold' level. Note that if the
// value of 'stdoutThreshold' is 'Severity::e_OFF', logging to 'stdout'
// is disabled.
void setLogFormat(const char *logFileFormat, const char *stdoutFormat);
// Set the format specifications for log records written to the log
// file and to 'stdout' to the specified 'logFileFormat' and
// 'stdoutFormat', respectively. If the default short output format is
// currently in effect for logging to 'stdout', this method has the
// effect of calling 'enableStdoutLoggingPrefix' (see that method and
// 'disableStdoutLoggingPrefix'). See {Log Record Formatting} for
// details on the syntax of format specifications. Note that default
// formats are in effect following construction until this method is
// called ("\n%d %p:%t %s %f:%l %c %m %u\n" for both file and 'stdout'
// logging). Also note that the observer emits newline characters at
// the beginning and at the end of a log record by default, so the user
// needs to add them explicitly to the format string to preserve this
// behavior.
void suppressUniqueFileNameOnRotation(bool suppress);
// Suppress generating a unique log file name upon rotation if the
// specified 'suppress' is 'true', and generate a unique filename
// otherwise. See {Rotated File Naming} for details.
// ACCESSORS
bslma::Allocator *allocator() const;
// Return the memory allocator used by this object.
void getLogFormat(const char **logFileFormat,
const char **stdoutFormat) const;
// Load the format specification for log records written by this file
// observer to the log file into the specified '*logFileFormat' address
// and the format specification for log records written to 'stdout'
// into the specified '*stdoutFormat' address. See {Log Record
// Formatting} for details on the syntax of format specifications.
bool isFileLoggingEnabled() const;
bool isFileLoggingEnabled(bsl::string *result) const;
bool isFileLoggingEnabled(std::string *result) const;
// Return 'true' if file logging is enabled for this file observer, and
// 'false' otherwise. Load the optionally specified 'result' with the
// name of the current log file if file logging is enabled, and leave
// 'result' unmodified otherwise. Note that records received through
// the 'publish' method of this file observer may still be logged to
// 'stdout' when this method returns 'false'.
#ifdef BSLS_LIBRARYFEATURES_HAS_CPP17_PMR
bool isFileLoggingEnabled(std::pmr::string *result) const;
// Return 'true' if file logging is enabled for this file observer, and
// 'false' otherwise. Load the specified 'result' with the name of the
// current log file if file logging is enabled, and leave 'result'
// unmodified otherwise. Note that records received through the
// 'publish' method of this file observer may still be logged to
// 'stdout' when this method returns 'false'.
#endif // BSLS_LIBRARYFEATURES_HAS_CPP17_PMR
bool isStdoutLoggingPrefixEnabled() const;
// Return 'true' if this file observer uses the long output format when
// writing to 'stdout', and 'false' otherwise (in which case the
// default short output format is used). See
// 'enableStdoutLoggingPrefix' and 'disableStdoutLoggingPrefix'.
bool isUserFieldsLoggingEnabled() const;
// Return 'true' if the logging of user-defined fields is enabled for
// this file observer, and 'false' otherwise.
//
// !DEPRECATED!: Do not use.
bool isPublishInLocalTimeEnabled() const;
// Return 'true' if this file observer writes the timestamp attribute
// of records that it publishes in local time, and 'false' otherwise
// (in which case timestamps are written in UTC time). Note that the
// value returned by this method also affects log filenames (see {Log
// Filename Patterns}).
bool isSuppressUniqueFileNameOnRotation() const;
// Return 'true' if the log filename uniqueness check on rotation is
// suppressed, and false otherwise.
bdlt::DatetimeInterval localTimeOffset() const;
// Return the difference between the local time and UTC time in effect
// when this file observer was constructed. Note that this value
// remains unchanged during the lifetime of this object and therefore
// may become incorrect when the difference between the local time and
// UTC time changes (e.g., when transitioning into or out of daylight
// savings time).
//
// !DEPRECATED!: Use 'bdlt::LocalTimeOffset' instead.
bdlt::DatetimeInterval rotationLifetime() const;
// Return the lifetime of the log file that will trigger a file
// rotation by this file observer if rotation-on-lifetime is in effect,
// and a 0 time interval otherwise.
int rotationSize() const;
// Return the size (in kilobytes) of the log file that will trigger a
// file rotation by this file observer if rotation-on-size is in
// effect, and 0 otherwise.
Severity::Level stdoutThreshold() const;
// Return the minimum severity of records that will be logged to
// 'stdout' by this file observer. Note that records with a threshold
// less severe than 'stdoutThreshold()' may still be output to the log
// file if file logging is enabled.
};
// ============================================================================
// INLINE DEFINITIONS
// ============================================================================
// ------------------
// class FileObserver
// ------------------
// MANIPULATORS
inline
void FileObserver::disableFileLogging()
{
d_fileObserver2.disableFileLogging();
}
inline
void FileObserver::disableLifetimeRotation()
{
d_fileObserver2.disableTimeIntervalRotation();
}
inline
void FileObserver::disableSizeRotation()
{
d_fileObserver2.disableSizeRotation();
}
inline
void FileObserver::disableTimeIntervalRotation()
{
d_fileObserver2.disableTimeIntervalRotation();
}
inline
int FileObserver::enableFileLogging(const char *logFilenamePattern)
{
return d_fileObserver2.enableFileLogging(logFilenamePattern);
}
inline
int FileObserver::enableFileLogging(const char *logFilenamePattern,
bool appendTimestampFlag)
{
return d_fileObserver2.enableFileLogging(logFilenamePattern,
appendTimestampFlag);
}
inline
void FileObserver::forceRotation()
{
d_fileObserver2.forceRotation();
}
inline
void FileObserver::publish(const bsl::shared_ptr<const Record>& record,
const Context& context)
{
publish(*record, context);
}
inline
void FileObserver::releaseRecords()
{
}
inline
void FileObserver::rotateOnLifetime(const bdlt::DatetimeInterval& timeInterval)
{
d_fileObserver2.rotateOnTimeInterval(timeInterval);
}
inline
void FileObserver::rotateOnSize(int size)
{
d_fileObserver2.rotateOnSize(size);
}
inline
void FileObserver::rotateOnTimeInterval(const bdlt::DatetimeInterval& interval)
{
d_fileObserver2.rotateOnTimeInterval(interval);
}
inline
void FileObserver::rotateOnTimeInterval(
const bdlt::DatetimeInterval& interval,
const bdlt::Datetime& startTime)
{
d_fileObserver2.rotateOnTimeInterval(interval, startTime);
}
inline
void FileObserver::setOnFileRotationCallback(
const OnFileRotationCallback& onRotationCallback)
{
d_fileObserver2.setOnFileRotationCallback(onRotationCallback);
}
inline
void FileObserver::suppressUniqueFileNameOnRotation(bool suppress)
{
d_fileObserver2.suppressUniqueFileNameOnRotation(suppress);
}
// ACCESSORS
inline
bool FileObserver::isFileLoggingEnabled() const
{
return d_fileObserver2.isFileLoggingEnabled();
}
inline
bool FileObserver::isFileLoggingEnabled(bsl::string *result) const
{
return d_fileObserver2.isFileLoggingEnabled(result);
}
inline
bool FileObserver::isFileLoggingEnabled(std::string *result) const
{
return d_fileObserver2.isFileLoggingEnabled(result);
}
#ifdef BSLS_LIBRARYFEATURES_HAS_CPP17_PMR
inline
bool FileObserver::isFileLoggingEnabled(std::pmr::string *result) const
{
return d_fileObserver2.isFileLoggingEnabled(result);
}
#endif //BSLS_LIBRARYFEATURES_HAS_CPP17_PMR
inline
bool FileObserver::isSuppressUniqueFileNameOnRotation() const
{
return d_fileObserver2.isSuppressUniqueFileNameOnRotation();
}
inline
bdlt::DatetimeInterval FileObserver::localTimeOffset() const
{
return d_fileObserver2.localTimeOffset();
}
inline
bdlt::DatetimeInterval FileObserver::rotationLifetime() const
{
return d_fileObserver2.rotationLifetime();
}
inline
int FileObserver::rotationSize() const
{
return d_fileObserver2.rotationSize();
}
} // close package namespace
} // close enterprise namespace
#endif
// ----------------------------------------------------------------------------
// Copyright 2015 Bloomberg Finance L.P.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ----------------------------- END-OF-FILE ----------------------------------