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Add ability for static base file and customizable file roll patterns. #345

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ee47592
Add ability for static base file and customizable file roll patterns.
jublin Mar 17, 2025
ece8bbb
Move file rather than copy.
jublin Mar 17, 2025
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42 changes: 31 additions & 11 deletions src/Serilog.Sinks.File/FileLoggerConfigurationExtensions.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -155,7 +155,8 @@ public static LoggerConfiguration File(
Encoding encoding)
{
return File(sinkConfiguration, path, restrictedToMinimumLevel, outputTemplate, formatProvider, fileSizeLimitBytes, levelSwitch, buffered,
shared, flushToDiskInterval, rollingInterval, rollOnFileSizeLimit, retainedFileCountLimit, encoding, null);
shared, flushToDiskInterval, rollingInterval, rollOnFileSizeLimit, retainedFileCountLimit, encoding, null,
null);
}

/// <summary>
Expand All @@ -164,7 +165,7 @@ public static LoggerConfiguration File(
/// <param name="sinkConfiguration">Logger sink configuration.</param>
/// <param name="formatter">A formatter, such as <see cref="JsonFormatter"/>, to convert the log events into
/// text for the file. If control of regular text formatting is required, use the other
/// overload of <see cref="File(LoggerSinkConfiguration, string, LogEventLevel, string, IFormatProvider, long?, LoggingLevelSwitch, bool, bool, TimeSpan?, RollingInterval, bool, int?, Encoding, FileLifecycleHooks, TimeSpan?)"/>
/// overload of <see cref="File(LoggerSinkConfiguration, string, LogEventLevel, string, IFormatProvider, long?, LoggingLevelSwitch, bool, bool, TimeSpan?, RollingInterval, bool, int?, Encoding, FileLifecycleHooks, TimeSpan?, bool, Func{DateTime?,string}?, string?)"/>
/// and specify the outputTemplate parameter instead.
/// </param>
/// <param name="path">Path to the file.</param>
Expand Down Expand Up @@ -236,6 +237,11 @@ public static LoggerConfiguration File(
/// Must be greater than or equal to <see cref="TimeSpan.Zero"/>.
/// Ignored if <paramref see="rollingInterval"/> is <see cref="RollingInterval.Infinite"/>.
/// The default is to retain files indefinitely.</param>
/// <param name="keepPathStaticOnRoll">Use the initial file path as a static file.</param>
/// <param name="customFormatFunc">A custom function that returns a custom string for rolling over files.
/// Accepts a DateTime for using custom DateTime formats.
/// This must return a string that can be matched by <paramref name="customRollPattern"/>.</param>
/// <param name="customRollPattern">A custom pattern for rolling over files. This must compile into a <see cref="System.Text.RegularExpressions.Regex"/> </param>
/// <returns>Configuration object allowing method chaining.</returns>
/// <exception cref="ArgumentNullException">When <paramref name="sinkConfiguration"/> is <code>null</code></exception>
/// <exception cref="ArgumentNullException">When <paramref name="path"/> is <code>null</code></exception>
Expand All @@ -262,7 +268,10 @@ public static LoggerConfiguration File(
int? retainedFileCountLimit = DefaultRetainedFileCountLimit,
Encoding? encoding = null,
FileLifecycleHooks? hooks = null,
TimeSpan? retainedFileTimeLimit = null)
TimeSpan? retainedFileTimeLimit = null,
bool keepPathStaticOnRoll = false,
Func<DateTime?,string>? customFormatFunc = null,
string? customRollPattern = null)
{
if (sinkConfiguration == null) throw new ArgumentNullException(nameof(sinkConfiguration));
if (path == null) throw new ArgumentNullException(nameof(path));
Expand All @@ -271,7 +280,7 @@ public static LoggerConfiguration File(
var formatter = new MessageTemplateTextFormatter(outputTemplate, formatProvider);
return File(sinkConfiguration, formatter, path, restrictedToMinimumLevel, fileSizeLimitBytes,
levelSwitch, buffered, shared, flushToDiskInterval,
rollingInterval, rollOnFileSizeLimit, retainedFileCountLimit, encoding, hooks, retainedFileTimeLimit);
rollingInterval, rollOnFileSizeLimit, retainedFileCountLimit, encoding, hooks, retainedFileTimeLimit, keepPathStaticOnRoll, customFormatFunc, customRollPattern);
}

/// <summary>
Expand All @@ -280,7 +289,7 @@ public static LoggerConfiguration File(
/// <param name="sinkConfiguration">Logger sink configuration.</param>
/// <param name="formatter">A formatter, such as <see cref="JsonFormatter"/>, to convert the log events into
/// text for the file. If control of regular text formatting is required, use the other
/// overload of <see cref="File(LoggerSinkConfiguration, string, LogEventLevel, string, IFormatProvider, long?, LoggingLevelSwitch, bool, bool, TimeSpan?, RollingInterval, bool, int?, Encoding, FileLifecycleHooks, TimeSpan?)"/>
/// overload of <see cref="File(LoggerSinkConfiguration, string, LogEventLevel, string, IFormatProvider, long?, LoggingLevelSwitch, bool, bool, TimeSpan?, RollingInterval, bool, int?, Encoding, FileLifecycleHooks, TimeSpan?, bool, Func{DateTime?, string}?, string?)"/>
/// and specify the outputTemplate parameter instead.
/// </param>
/// <param name="path">Path to the file.</param>
Expand All @@ -306,6 +315,9 @@ public static LoggerConfiguration File(
/// Must be greater than or equal to <see cref="TimeSpan.Zero"/>.
/// Ignored if <paramref see="rollingInterval"/> is <see cref="RollingInterval.Infinite"/>.
/// The default is to retain files indefinitely.</param>
/// <param name="keepPathStaticOnRoll">Use the initial file path as a static file.</param>
/// <param name="customFormatFunc">A custom function that returns a custom string for rolling over files. This must return a string that can be matched by <paramref name="customRollPattern"/>.</param>
/// <param name="customRollPattern">A custom pattern for rolling over files. This must compile into a <see cref="System.Text.RegularExpressions.Regex"/> </param>
/// <returns>Configuration object allowing method chaining.</returns>
/// <exception cref="ArgumentNullException">When <paramref name="sinkConfiguration"/> is <code>null</code></exception>
/// <exception cref="ArgumentNullException">When <paramref name="formatter"/> is <code>null</code></exception>
Expand All @@ -331,15 +343,18 @@ public static LoggerConfiguration File(
int? retainedFileCountLimit = DefaultRetainedFileCountLimit,
Encoding? encoding = null,
FileLifecycleHooks? hooks = null,
TimeSpan? retainedFileTimeLimit = null)
TimeSpan? retainedFileTimeLimit = null,
bool keepPathStaticOnRoll = false,
Func<DateTime?,string>? customFormatFunc = null,
string? customRollPattern = null)
{
if (sinkConfiguration == null) throw new ArgumentNullException(nameof(sinkConfiguration));
if (formatter == null) throw new ArgumentNullException(nameof(formatter));
if (path == null) throw new ArgumentNullException(nameof(path));

return ConfigureFile(sinkConfiguration.Sink, formatter, path, restrictedToMinimumLevel, fileSizeLimitBytes, levelSwitch,
buffered, false, shared, flushToDiskInterval, encoding, rollingInterval, rollOnFileSizeLimit,
retainedFileCountLimit, hooks, retainedFileTimeLimit);
retainedFileCountLimit, hooks, retainedFileTimeLimit, keepPathStaticOnRoll, customFormatFunc, customRollPattern);
}

/// <summary>
Expand Down Expand Up @@ -487,14 +502,15 @@ public static LoggerConfiguration File(
LogEventLevel restrictedToMinimumLevel = LevelAlias.Minimum,
LoggingLevelSwitch? levelSwitch = null,
Encoding? encoding = null,
FileLifecycleHooks? hooks = null)
FileLifecycleHooks? hooks = null
)
{
if (sinkConfiguration == null) throw new ArgumentNullException(nameof(sinkConfiguration));
if (formatter == null) throw new ArgumentNullException(nameof(formatter));
if (path == null) throw new ArgumentNullException(nameof(path));

return ConfigureFile(sinkConfiguration.Sink, formatter, path, restrictedToMinimumLevel, null, levelSwitch, false, true,
false, null, encoding, RollingInterval.Infinite, false, null, hooks, null);
false, null, encoding, RollingInterval.Infinite, false, null, hooks, null, false, null, null);
}

static LoggerConfiguration ConfigureFile(
Expand All @@ -513,7 +529,10 @@ static LoggerConfiguration ConfigureFile(
bool rollOnFileSizeLimit,
int? retainedFileCountLimit,
FileLifecycleHooks? hooks,
TimeSpan? retainedFileTimeLimit)
TimeSpan? retainedFileTimeLimit,
bool keepPathStaticOnRoll,
Func<DateTime?,string>? customFormatFunc,
string? customRollPattern)
{
if (addSink == null) throw new ArgumentNullException(nameof(addSink));
if (formatter == null) throw new ArgumentNullException(nameof(formatter));
Expand All @@ -523,14 +542,15 @@ static LoggerConfiguration ConfigureFile(
if (retainedFileTimeLimit.HasValue && retainedFileTimeLimit < TimeSpan.Zero) throw new ArgumentException("Negative value provided; retained file time limit must be non-negative.", nameof(retainedFileTimeLimit));
if (shared && buffered) throw new ArgumentException("Buffered writes are not available when file sharing is enabled.", nameof(buffered));
if (shared && hooks != null) throw new ArgumentException("File lifecycle hooks are not currently supported for shared log files.", nameof(hooks));
if(keepPathStaticOnRoll && (fileSizeLimitBytes == null && rollingInterval == RollingInterval.Infinite )) throw new ArgumentException("keepPathStaticOnRoll is only supported when either fileSizeLimitBytes or rollingInterval are enabled");

ILogEventSink sink;

try
{
if (rollOnFileSizeLimit || rollingInterval != RollingInterval.Infinite)
{
sink = new RollingFileSink(path, formatter, fileSizeLimitBytes, retainedFileCountLimit, encoding, buffered, shared, rollingInterval, rollOnFileSizeLimit, hooks, retainedFileTimeLimit);
sink = new RollingFileSink(path, formatter, fileSizeLimitBytes, retainedFileCountLimit, encoding, buffered, shared, rollingInterval, rollOnFileSizeLimit, hooks, retainedFileTimeLimit, keepPathStaticOnRoll, customFormatFunc, customRollPattern);
}
else
{
Expand Down
19 changes: 16 additions & 3 deletions src/Serilog.Sinks.File/Sinks/File/FileSink.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,7 @@ public sealed class FileSink : IFileSink, IDisposable, ISetLoggingFailureListene
/// <param name="encoding">Character encoding used to write the text file. The default is UTF-8 without BOM.</param>
/// <param name="buffered">Indicates if flushing to the output file can be buffered or not. The default
/// is false.</param>
/// <param name="keepPathStatic">Indicates that the path is static/persistent</param>
/// <returns>Configuration object allowing method chaining.</returns>
/// <remarks>This constructor preserves compatibility with early versions of the public API. New code should not depend on this type.</remarks>
/// <exception cref="ArgumentNullException">When <paramref name="textFormatter"/> is <code>null</code></exception>
Expand All @@ -56,7 +57,7 @@ public sealed class FileSink : IFileSink, IDisposable, ISetLoggingFailureListene
/// <exception cref="UnauthorizedAccessException">The caller does not have the required permission to access the <paramref name="path"/></exception>
/// <exception cref="ArgumentException">Invalid <paramref name="path"/></exception>
[Obsolete("This type and constructor will be removed from the public API in a future version; use `WriteTo.File()` instead.")]
public FileSink(string path, ITextFormatter textFormatter, long? fileSizeLimitBytes, Encoding? encoding = null, bool buffered = false)
public FileSink(string path, ITextFormatter textFormatter, long? fileSizeLimitBytes, Encoding? encoding = null, bool buffered = false, bool keepPathStatic = false)
: this(path, textFormatter, fileSizeLimitBytes, encoding, buffered, null)
{
}
Expand All @@ -68,7 +69,9 @@ internal FileSink(
long? fileSizeLimitBytes,
Encoding? encoding,
bool buffered,
FileLifecycleHooks? hooks)
FileLifecycleHooks? hooks,
bool keepPathStatic = false
)
{
if (path == null) throw new ArgumentNullException(nameof(path));
if (fileSizeLimitBytes is < 1) throw new ArgumentException("Invalid value provided; file size limit must be at least 1 byte, or null.");
Expand All @@ -82,7 +85,16 @@ internal FileSink(
Directory.CreateDirectory(directory);
}

Stream outputStream = _underlyingStream = System.IO.File.Open(path, FileMode.OpenOrCreate, FileAccess.Write, FileShare.Read);
FileMode fileOpenMode;
if (System.IO.File.Exists(path) && keepPathStatic)
{
fileOpenMode = FileMode.Truncate;
}
else
{
fileOpenMode = FileMode.OpenOrCreate;
}
Stream outputStream = _underlyingStream = System.IO.File.Open(path, fileOpenMode, FileAccess.Write, FileShare.Read);
outputStream.Seek(0, SeekOrigin.End);

if (_fileSizeLimitBytes != null)
Expand All @@ -99,6 +111,7 @@ internal FileSink(
{
outputStream = hooks.OnFileOpened(path, outputStream, encoding) ??
throw new InvalidOperationException($"The file lifecycle hook `{nameof(FileLifecycleHooks.OnFileOpened)}(...)` returned `null`.");

}
catch
{
Expand Down
125 changes: 114 additions & 11 deletions src/Serilog.Sinks.File/Sinks/File/PathRoller.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -26,15 +26,29 @@ sealed class PathRoller
readonly string _filenamePrefix;
readonly string _filenameSuffix;
readonly Regex _filenameMatcher;
readonly bool _keepPathStatic;
readonly string? _customRollPattern;
private Func<DateTime?, string>? _customFormatFunc;

readonly RollingInterval _interval;
readonly string _periodFormat;

public PathRoller(string path, RollingInterval interval)
public PathRoller(string path, RollingInterval interval, bool keepPathStatic = false, Func<DateTime?,string>? customFormatFunc = null,
string? customRollPattern = null)
{
if (path == null) throw new ArgumentNullException(nameof(path));
_interval = interval;
_periodFormat = interval.GetFormat();
_keepPathStatic = keepPathStatic;
_customRollPattern = customRollPattern;
_customFormatFunc = customFormatFunc;

if (_customRollPattern != null && _customFormatFunc != null)
{
ValidateCustomRollPattern(_customRollPattern);
ValidateCustomFormatFuncMatchesPattern(customFormatFunc, _customRollPattern);
}



var pathDirectory = Path.GetDirectoryName(path);
if (string.IsNullOrEmpty(pathDirectory))
Expand All @@ -43,30 +57,107 @@ public PathRoller(string path, RollingInterval interval)
_directory = Path.GetFullPath(pathDirectory);
_filenamePrefix = Path.GetFileNameWithoutExtension(path);
_filenameSuffix = Path.GetExtension(path);
_filenameMatcher = new Regex(
if (_customRollPattern == null)
{
_periodFormat = interval.GetFormat();
_filenameMatcher = new Regex(
"^" +
Regex.Escape(_filenamePrefix) +
"(?<" + PeriodMatchGroup + ">\\d{" + _periodFormat.Length + "})" +
"(?<" + SequenceNumberMatchGroup + ">_[0-9]{3,}){0,1}" +
Regex.Escape(_filenameSuffix) +
"$",
RegexOptions.Compiled);
}
else
{
_periodFormat = _customRollPattern;
_filenameMatcher = new Regex(
"^" +
Regex.Escape(_filenamePrefix) +
"(?<" + PeriodMatchGroup + ">\\d{" + _periodFormat.Length + "})" +
"(?<" + SequenceNumberMatchGroup + ">_[0-9]{3,}){0,1}" +
Regex.Escape(_filenameSuffix) +
"$",
Regex.Escape(_filenamePrefix) +
"(?<" + PeriodMatchGroup + ">" + _customRollPattern + ")" +
"(?<" + SequenceNumberMatchGroup + ">_[0-9]{3,}){0,1}" +
Regex.Escape(_filenameSuffix) +
"$",
RegexOptions.Compiled);
}

DirectorySearchPattern = $"{_filenamePrefix}*{_filenameSuffix}";
}

private void ValidateCustomFormatFuncMatchesPattern(Func<DateTime?, string>? customFormatFunc, string customRollPattern)
{
var temp = customFormatFunc?.Invoke(DateTime.Now);
if (temp == null)
{
throw new ArgumentException("Custom format function did not return a value.", nameof(customFormatFunc));
}

if (!Regex.IsMatch(temp, customRollPattern))
{
throw new ArgumentException($"Custom format function does not match the custom roll pattern of {customRollPattern}.", nameof(customFormatFunc));
}

}

public string LogFileDirectory => _directory;

public string DirectorySearchPattern { get; }

public void GetLogFilePath(DateTime date, int? sequenceNumber, out string path)
public void GetLogFilePath(DateTime date, int? sequenceNumber, out string path, out string? copyPath)
{
var currentCheckpoint = GetCurrentCheckpoint(date);

var tok = currentCheckpoint?.ToString(_periodFormat, CultureInfo.InvariantCulture) ?? "";
var tok = GetToken(sequenceNumber, currentCheckpoint);

if (_keepPathStatic)
{
path = Path.Combine(_directory, _filenamePrefix + _filenameSuffix);

copyPath = Path.Combine(_directory, _filenamePrefix + tok + _filenameSuffix);
return;
}

copyPath = null;
GetLogFilePath(date, sequenceNumber, out path);
}

private string GetToken(int? sequenceNumber, DateTime? currentCheckpoint)
{
var tok = string.Empty;

if (sequenceNumber != null)
if (_customFormatFunc == null)
{
tok = currentCheckpoint?.ToString(_periodFormat, CultureInfo.InvariantCulture) ?? "";
}
else if( _customFormatFunc != null && sequenceNumber == null && currentCheckpoint != null)
{
tok = _customFormatFunc.Invoke(currentCheckpoint);
}
else if( _customFormatFunc != null && sequenceNumber != null && currentCheckpoint == null)
{
tok = _customFormatFunc.Invoke(DateTime.Now);
}
else if (_customFormatFunc != null && sequenceNumber == null && currentCheckpoint == null)
{
return string.Empty;
}

if (sequenceNumber == null) return tok;
var path = Path.Combine(_directory, _filenamePrefix + tok + _filenameSuffix);
if (System.IO.File.Exists(path))
{
tok += "_" + sequenceNumber.Value.ToString("000", CultureInfo.InvariantCulture);
}

return tok;
}

public void GetLogFilePath(DateTime date, int? sequenceNumber, out string path)
{
var currentCheckpoint = GetCurrentCheckpoint(date);

var tok = GetToken(sequenceNumber, currentCheckpoint);

path = Path.Combine(_directory, _filenamePrefix + tok + _filenameSuffix);
}
Expand Down Expand Up @@ -110,4 +201,16 @@ public IEnumerable<RollingLogFile> SelectMatches(IEnumerable<string> filenames)
public DateTime? GetCurrentCheckpoint(DateTime instant) => _interval.GetCurrentCheckpoint(instant);

public DateTime? GetNextCheckpoint(DateTime instant) => _interval.GetNextCheckpoint(instant);

private void ValidateCustomRollPattern(string pattern)
{
try
{
_ = new Regex(pattern);
}
catch (ArgumentException)
{
throw new ArgumentException("The custom roll pattern is not a valid regex pattern.", nameof(pattern));
}
}
}
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