58 lines
3.5 KiB
Markdown
58 lines
3.5 KiB
Markdown
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streamroller
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============
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node.js file streams that roll over when they reach a maximum size, or a date/time.
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npm install streamroller
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## usage
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var rollers = require('streamroller');
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var stream = new rollers.RollingFileStream('myfile', 1024, 3);
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stream.write("stuff");
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stream.end();
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The streams behave the same as standard node.js streams, except that when certain conditions are met they will rename the current file to a backup and start writing to a new file.
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### new RollingFileStream(filename [, maxSize, numBackups, options])
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* `filename` (String)
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* `maxSize` - the size in bytes to trigger a rollover, if not provided this defaults to MAX_SAFE_INTEGER and the stream will not roll.
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* `numBackups` - the number of old files to keep
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* `options` - Object
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* `encoding` - defaults to 'utf8'
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* `mode` - defaults to 0644
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* `flags` - defaults to 'a' (see [fs.open](https://nodejs.org/dist/latest-v8.x/docs/api/fs.html#fs_fs_open_path_flags_mode_callback) for more details)
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* `compress` - (boolean) defaults to `false` - compress the backup files using gzip (files will have `.gz` extension).
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* `keepFileExt` - (boolean) defaults to `false` - keep the file original extension. e.g.: `abc.log -> abc.1.log`.
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This returns a `WritableStream`. When the current file being written to (given by `filename`) gets up to or larger than `maxSize`, then the current file will be renamed to `filename.1` and a new file will start being written to. Up to `numBackups` of old files are maintained, so if `numBackups` is 3 then there will be 4 files:
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<pre>
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filename
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filename.1
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filename.2
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filename.3
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</pre>
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When filename size >= maxSize then:
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<pre>
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filename -> filename.1
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filename.1 -> filename.2
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filename.2 -> filename.3
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filename.3 gets overwritten
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filename is a new file
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</pre>
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### new DateRollingFileStream(filename, pattern, options)
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* `filename` (String)
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* `pattern` (String) - the date pattern to trigger rolling (see below)
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* `options` - Object
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* `encoding` - defaults to 'utf8'
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* `mode` defaults to 0644
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* `flags` defaults to 'a' (see [fs.open](https://nodejs.org/dist/latest-v8.x/docs/api/fs.html#fs_fs_open_path_flags_mode_callback) for more details)
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* `compress` - (boolean) compress the backup files, defaults to false
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* `keepFileExt` - (boolean) defaults to `false` - keep the file original extension. e.g.: `abc.log -> abc.2013-08-30.log`.
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* `alwaysIncludePattern` - (boolean) extend the initial file with the pattern, defaults to false
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* `daysToKeep` - (integer) if this is greater than 0, then files older than `daysToKeep` days will be deleted during file rolling.
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This returns a `WritableStream`. When the current time, formatted as `pattern`, changes then the current file will be renamed to `filename.formattedDate` where `formattedDate` is the result of processing the date through the pattern, and a new file will begin to be written. Streamroller uses [date-format](http://github.com/nomiddlename/date-format) to format dates, and the `pattern` should use the date-format format. e.g. with a `pattern` of `".yyyy-MM-dd"`, and assuming today is August 29, 2013 then writing to the stream today will just write to `filename`. At midnight (or more precisely, at the next file write after midnight), `filename` will be renamed to `filename.2013-08-29` and a new `filename` will be created. If `options.alwaysIncludePattern` is true, then the initial file will be `filename.2013-08-29` and no renaming will occur at midnight, but a new file will be written to with the name `filename.2013-08-30`.
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