flexi_logger

Fix issue-94 - kudos to leishiao!

Platform-specific fixes, and introduction of github-actions-based CI. Kudos to dallenng and HEnquist!

FileLogWriter has been functionally extended to make it usable "stand-alone". As part of that, the FlWriteMode is gone, and the normal WriteMode is used.

WriteMode::BufferDontFlushWith was added.

A new experimental feature (and module) "trc" allows using flexi_logger functionality with tracing.

Error handling is improved, error codes are documented comprehensively, errors now also print a link to the error documentation.

Default color for DEBUG lines was changed (fixes issue-88, kudos goes to HEnquist!).

Test coverage is improved.

Implement async mode also for log_to_stdout() and log_to_stderr().

Significant API revision, to better cope with new features and for better readability/applicability.

Most important changes:

• Better error handling in factory methods:
  • Logger::with_env() is replaced with Logger::try_with_env(), which returns a Result
  • Logger::with_str() is replaced with Logger::try_with_str(), which returns a Result
  • Logger::with_env_or_str() is replaced with Logger::try_with_env_or_str(), which returns a Result
  • consequently, the method Logger::check_parser_error is gone
• Bundling file-related aspects
  • introduction of FileSpec
  • move of filename-related methods from Logger to FileSpec (and similarly on the FileLogWriter)
• Logger::log_target(LogTarget) is replaced with a set of methods
  • Logger::log_to_file(FileSpec)
  • Logger::log_to_stdout()
  • Logger::log_to_stderr()
  • Logger::log_to_writer(Box<dyn LogWriter>)
  • Logger::log_to_file_and_writer(FileSpec,Box<dyn LogWriter>)
  • Logger::do_not_log()
• The new method Logger::write_mode(WriteMode)
  • replaces several methods to control buffer handling etc
  • offers additionally asynchronous file I/O (if the crate feature async is used)
• Keeping the LoggerHandle alive has become crucial (except for trivial cases)!
• Several methods are now more generic with their input parameters
• A new method LoggerHandle::reset_flw allows reconfiguring a used FileLogWriter at runtime

Added an option to apply a stateful filter before log lines are really written (kudos to jesdazrez (Jesús Trinidad Díaz Ramírez)!).

Fixed error handling in logspec parsing (wrong error was thrown).

Several docu improvements.

Add options Logger::buffer_and_flush() and buffer_and_flush_with() as means to avoid long output delays.

Introduce optional buffering of log output. This increases performance (which can be relevant for programs with really high log production), but delays log line appearance in the output, which can be confusing, and requires to flush or shutdown the logger at the end of the program to ensure that all logs are written to the output before the program terminates.

Reduce the size of LogConfiguration considerably by moving the optional and rarely used textfilter into the heap. This unfortunately leads to an incompatible change in a rarely used public method (LogConfiguration::text_filter() was returning a &Option<Regex>, and is now returning Option<&Regex>), which enforces a version bump.

Rename ReconfigurationHandle to LoggerHandle (and add an type alias with the old name).

Add the public method LoggerHandle::flush().

Expose DeferredNow::new().

Add some must_use annotations where appropriate.

Add module code-examples with additional usage documentation. This is a follow-up of a PR, kudos goes to devzbysiu!

Support empty toml spec files (kudos to ijackson for pull request 66!) (was supposed to be part of 0.16.0, but I had forgotten to merge it).

If file logging is used, do not create the output file if no log is written. Solves issue-62.

Improve color handling

• introduce AdaptiveFormat for a clearer API
• Support using feature atty without provided coloring
• Extend example colors to provide insight in how AdaptiveFormat works
• Remove the deprecated method Logger::do_not_log(); use log_target() with LogTarget::DevNull instead.
• Remove deprecated method Logger::o_log_to_file(); use log_target() instead. The clearer convenience method Logger::log_to_file() is still available.

Improve the compression feature. Solves issue-65.

• breaking change: change the file suffix for the compressed log files from .zip to .gz
• Fix wrong wording in code and documentation
• deprecate the feature name ziplog and call the feature now compress
• rename Cleanup::KeepZipFiles into Cleanup::KeepCompressedFiles and Cleanup::KeepLogAndZipFiles into Cleanup::KeepLogAndCompressedFiles
  • the old names still work but are deprecated

If file logging is used, do not create the output file if no log is written Solves issue issue-62.

Make 1.37.0 the minimal rust version for flexi_logger.

Introduce feature specfile_without_notification to allow coping with OS issues (solves issue-59).

Minor code maintenance.

Allow using the log target with fantasy names, like with env_logger. Solves issue-56.

Allow modifying the coloring palette through the environment variable FLEXI_LOGGER_PALETTE. See function style for details. Solves issue-55.

By default, don't use colors if stdout or stderr are not a terminal Solves issue-57.

Add variant Criterion::AgeOrSize (kudos to pscott!, PR-54).

Add some Debug derives (kudos to pscott!, PR-52).

Introduce separate formatting for stdout (kudos to pscott!, PR-51).

Deprecate Logger::do_not_log().

Add Logger::duplicate_to_stdout() to fix issue-47.

Fix issue-45, which was a panic in the specfile watcher when some log files were deleted manually while the program was running (kudos to avl!, PR-46).

Add compatibility with multi_log by adding methods Logger::build and Logger::build_with_specfile (fixes issue-44).

Add LogSpecBuilder::insert_modules_from() (fixes issue-43).

Improve handling of parse-errors.

Fix default format for files (was and is documented to be uncolored, but was colored).

Make the textfilter functionality an optional default feature; deselecting it removes the regex crate as a required dependency, which reduces the size overhead for any binary using flexi_logger (kudos to Petre Eftime!).

Refine and rename error variants to allow e.g. differentiating between errors related to the output (files) and errors related to the specfile.

Make cleanup more robust, and allow controlling the cleanup-thread also with Logger::start_with_specfile().

If rotation is used with cleanup, do the cleanup by default in a background thread (solves issue 39).

For the ziplog feature, switch from zip crate to flate2.

Fix issue 38 (Old log files are not removed if rCURRENT doesn't overflow).

Pass format option into custom loggers (pull request 37).

Fix bug in specfile handling (issue 36).

Improve docu and implementation of create_symlink.

Minor other stuff.

Allow defining custom handlers for the default log target (solves issue 32).

Use implicit locking of stderr in StdErrWriter.

Allow failures in travis' windows build.

Add license files.

Support recursive logging also with FileLogWriter, sharing the buffer with the PrimaryWriter.

Fix multi-threading issue (incorrect line-break handling with stderr).

Further stabilize the specfile feature.

Remove LogSpecification::ensure_specfile_exists() and LogSpecification::from_file() from public API, where they should not be (-> version bump).

Harmonize all eprintln! calls to prefix the output with "[flexi_logger] ".

Only relevant for the specfile feature: initialize the logger before dealing in any way with the specfile, and do the initial read of the specfile in the main thread, i.e. synchronously, to ensure a deterministic behavior during startup (fixes issue 31).

Improve the file watch for the specfile to make the specfile feature more robust. E.g. allow editing the specfile on linux with editors that move the original file to a backup name.

Add an option to write the log to stdout, as recommended for twelve-factor apps.

Make get_creation_date() more robust on all platforms.

Fix fatal issue with get_creation_date() on linux (see https://github.com/emabee/flexi_logger/pull/30).

Improve performance for plain stderr logging.

Improve robustnesss for recursive log calls.

Revise handling of record.metadata().target() versus record.module_path().

Incompatible API modification: Logger.rotate() takes now three parameters.

Suppport different formatting for stderr and files.

Add feature colors (see README.md for details).

Remove the deprecated Logger::start_reconfigurable() and Logger::rotate_over_size().

Fix issue 26 (logging off for specific modules).

Fix issue 27 (log files blank after restart).

Fix issue 28 (add a corresponding set of unit tests to FileLogWriter).

Version updates of dependencies.

Add SyslogWriter.

Change API to more idiomatic parameter types, in a compatible way.

Add first implementation of a SyslogWriter.

Add option to write windows line endings, rather than a plain \n.

Add options to cleanup rotated log files, by deleting and/or zipping older files.

Remove some deprecated methods.

Let the BlackHoleLogger, although it doesn't write a log, still duplicate to stderr.

Deprecate Logger::start_reconfigurable(), let Logger::start() return a reconfiguration handle.

Add an option to write all logs to nowhere (i.e., do not write any logs).

Eliminate performance penalty for using reconfigurability.

Add methods to modify the log spec temporarily.

Advance to edition 2018.

Log-spec parsing is improved, more whitespace is tolerated.

When file rotation is used, the name of the file to which the logs are written is now stable.

Details:

• the logs are always written to a file with infix _rCURRENT
• if this file exceeds the specified rotate-over-size, it is closed and renamed to a file with a sequential number infix, and then the logging continues again to the (fresh) file with infix _rCURRENT

Example:

After some logging with your program my_prog, you will find files like

my_prog_r00000.log
my_prog_r00001.log
my_prog_r00002.log
my_prog_rCURRENT.log

LogSpecification::parse() now returns a Result<LogSpecification, FlexiLoggerError>, rather than a log spec directly (-> version bump). This enables a more reliable usage of FlexiLogger in non-trivial cases.

For the sake of compatibility for the normal usecases, the Logger methods with_str() etc. remain unchanged. An extra method is added to retrieve parser errors, if desired.

Docu improvement.

Fix incorrect filename generation with rotation, i.e., switch off timestamp usage when rotation is used.

Introduce Logger::duplicate_to_stderr(), as a more flexible replacement for duplicate_error() and duplicate_info().