youtubebeat/vendor/github.com/elastic/beats/filebeat/docs/inputs/input-common-file-options.asciidoc

//////////////////////////////////////////////////////////////////////////
//// This content is shared by Filebeat inputs that use the prospector
//// to process files on disk (includes options for managing physical files)
//// If you add IDs to sections, make sure you use attributes to create
//// unique IDs for each input that includes this file. Use the format:
//// [id="{beatname_lc}-input-{type}-option-name"]
//////////////////////////////////////////////////////////////////////////

[float]
[id="{beatname_lc}-input-{type}-exclude-files"]
===== `exclude_files`

A list of regular expressions to match the files that you want {beatname_uc} to
ignore. By default no files are excluded.

The following example configures {beatname_uc} to ignore all the files that have
a `gz` extension:

["source","yaml",subs="attributes"]
----
{beatname_lc}.inputs:
- type: {type}
  ...
  exclude_files: ['\.gz$']
----

See <<regexp-support>> for a list of supported regexp patterns.

[float]
[id="{beatname_lc}-input-{type}-ignore-older"]
===== `ignore_older`

If this option is enabled, {beatname_uc} ignores any files that were modified
before the specified timespan. Configuring `ignore_older` can be especially
useful if you keep log files for a long time. For example, if you want to start
{beatname_uc}, but only want to send the newest files and files from last week,
you can configure this option.

You can use time strings like 2h (2 hours) and 5m (5 minutes). The default is 0,
which disables the setting. Commenting out the config has the same effect as
setting it to 0.

IMPORTANT: You must set `ignore_older` to be greater than `close_inactive`.

The files affected by this setting fall into two categories:

* Files that were never harvested
* Files that were harvested but weren't updated for longer than `ignore_older`

For files which were never seen before, the offset state is set to the end of
the file. If a state already exist, the offset is not changed. In case a file is
updated again later, reading continues at the set offset position.

The `ignore_older` setting relies on the modification time of the file to
determine if a file is ignored. If the modification time of the file is not
updated when lines are written to a file (which can happen on Windows), the
`ignore_older` setting may cause {beatname_uc} to ignore files even though
content was added at a later time.

To remove the state of previously harvested files from the registry file, use
the `clean_inactive` configuration option.

Before a file can be ignored by {beatname_uc}, the file must be closed. To
ensure a file is no longer being harvested when it is ignored, you must set
`ignore_older` to a longer duration than `close_inactive`.

If a file that's currently being harvested falls under `ignore_older`, the
harvester will first finish reading the file and close it after `close_inactive`
is reached. Then, after that, the file will be ignored.

[float]
[id="{beatname_lc}-input-{type}-close-options"]
===== `close_*`

The `close_*` configuration options are used to close the harvester after a
certain criteria or time. Closing the harvester means closing the file handler.
If a file is updated after the harvester is closed, the file will be picked up
again after `scan_frequency` has elapsed. However, if the file is moved or
deleted while the harvester is closed, {beatname_uc} will not be able to pick up
the file again, and any data that the harvester hasn't read will be lost.


[float]
[id="{beatname_lc}-input-{type}-close-inactive"]
===== `close_inactive`

When this option is enabled, {beatname_uc} closes the file handle if a file has
not been harvested for the specified duration. The counter for the defined
period starts when the last log line was read by the harvester. It is not based
on the modification time of the file. If the closed file changes again, a new
harvester is started and the latest changes will be picked up after
`scan_frequency` has elapsed.

We recommended that you set `close_inactive` to a value that is larger than the
least frequent updates to your log files. For example, if your log files get
updated every few seconds, you can safely set `close_inactive` to `1m`. If there
are log files with very different update rates, you can use multiple 
configurations with different values.

Setting `close_inactive` to a lower value means that file handles are closed
sooner. However this has the side effect that new log lines are not sent in near
real time if the harvester is closed.

The timestamp for closing a file does not depend on the modification time of the
file. Instead, {beatname_uc} uses an internal timestamp that reflects when the
file was last harvested. For example, if `close_inactive` is set to 5 minutes,
the countdown for the 5 minutes starts after the harvester reads the last line
of the file.

You can use time strings like 2h (2 hours) and 5m (5 minutes). The default is
5m.

[float]
[id="{beatname_lc}-input-{type}-close-renamed"]
===== `close_renamed`

WARNING: Only use this option if you understand that data loss is a potential
side effect.

When this option is enabled, {beatname_uc} closes the file handler when a file
is renamed. This happens, for example, when rotating files. By default, the
harvester stays open and keeps reading the file because the file handler does
not depend on the file name. If the `close_renamed` option is enabled and the
file is renamed or moved in such a way that it's no longer matched by the file
patterns specified for the , the file will not be picked up again.
{beatname_uc} will not finish reading the file.

WINDOWS: If your Windows log rotation system shows errors because it can't
rotate the files, you should enable this option.

[float]
[id="{beatname_lc}-input-{type}-close-removed"]
===== `close_removed`

When this option is enabled, {beatname_uc} closes the harvester when a file is
removed. Normally a file should only be removed after it's inactive for the
duration specified by `close_inactive`. However, if a file is removed early and
you don't enable `close_removed`, {beatname_uc} keeps the file open to make sure
the harvester has completed. If this setting results in files that are not
completely read because they are removed from disk too early, disable this
option.

This option is enabled by default. If you disable this option, you must also
disable `clean_removed`.

WINDOWS: If your Windows log rotation system shows errors because it can't
rotate files, make sure this option is enabled.

[float]
[id="{beatname_lc}-input-{type}-close-eof"]
===== `close_eof`

WARNING: Only use this option if you understand that data loss is a potential
side effect.

When this option is enabled, {beatname_uc} closes a file as soon as the end of a
file is reached. This is useful when your files are only written once and not
updated from time to time. For example, this happens when you are writing every
single log event to a new file. This option is disabled by default.

[float]
[id="{beatname_lc}-input-{type}-close-timeout"]
===== `close_timeout`

WARNING: Only use this option if you understand that data loss is a potential
side effect. Another side effect is that multiline events might not be
completely sent before the timeout expires.

When this option is enabled, {beatname_uc} gives every harvester a predefined
lifetime. Regardless of where the reader is in the file, reading will stop after
the `close_timeout` period has elapsed. This option can be useful for older log
files when you want to spend only a predefined amount of time on the files.
While `close_timeout` will close the file after the predefined timeout, if the
file is still being updated, {beatname_uc} will start a new harvester again per
the defined `scan_frequency`. And the close_timeout for this harvester will
start again with the countdown for the timeout.

This option is particularly useful in case the output is blocked, which makes
{beatname_uc} keep open file handlers even for files that were deleted from the
disk. Setting `close_timeout` to `5m` ensures that the files are periodically
closed so they can be freed up by the operating system.

If you set `close_timeout` to equal `ignore_older`, the file will not be picked
up if it's modified while the harvester is closed. This combination of settings
normally leads to data loss, and the complete file is not sent.

When you use `close_timeout` for logs that contain multiline events, the
harvester might stop in the middle of a multiline event, which means that only
parts of the event will be sent. If the harvester is started again and the file
still exists, only the second part of the event will be sent.

This option is set to 0 by default which means it is disabled.


[float]
[id="{beatname_lc}-input-{type}-clean-options"]
===== `clean_*`

The `clean_*` options are used to clean up the state entries in the registry
file. These settings help to reduce the size of the registry file and can
prevent a potential <<inode-reuse-issue,inode reuse issue>>.

[float]
[id="{beatname_lc}-input-{type}-clean-inactive"]
===== `clean_inactive`

WARNING: Only use this option if you understand that data loss is a potential
side effect.

When this option is enabled, {beatname_uc} removes the state of a file after the
specified period of inactivity has elapsed. The  state can only be removed if
the file is already ignored by {beatname_uc} (the file is older than
`ignore_older`). The `clean_inactive` setting must be greater than `ignore_older +
scan_frequency` to make sure that no states are removed while a file is still
being harvested. Otherwise, the setting could result in {beatname_uc} resending
the full content constantly because  `clean_inactive` removes state for files
that are still detected by {beatname_uc}. If a file is updated or appears
again, the file is read from the beginning.

The `clean_inactive` configuration option is useful to reduce the size of the
registry file, especially if a large amount of new files are generated every
day.

This config option is also useful to prevent {beatname_uc} problems resulting
from inode reuse on Linux. For more information, see <<inode-reuse-issue>>.

NOTE: Every time a file is renamed, the file state is updated and the counter
for `clean_inactive` starts at 0 again.

[float]
[id="{beatname_lc}-input-{type}-clean-removed"]
===== `clean_removed`

When this option is enabled, {beatname_uc} cleans files from the registry if
they cannot be found on disk anymore under the last known name. This means also
files which were renamed after the harvester was finished will be removed. This
option is enabled by default.

If a shared drive disappears for a short period and appears again, all files
will be read again from the beginning because the states were removed from the
registry file. In such cases, we recommend that you disable the `clean_removed`
option.

You must disable this option if you also disable `close_removed`.

[float]
[id="{beatname_lc}-input-{type}-scan-frequency"]
===== `scan_frequency`

How often {beatname_uc} checks for new files in the paths that are specified
for harvesting. For example, if you specify a glob like `/var/log/*`, the
directory is scanned for files using the frequency specified by
`scan_frequency`. Specify 1s to scan the directory as frequently as possible
without causing {beatname_uc} to scan too frequently. We do not recommend to set
this value `<1s`.

If you require log lines to be sent in near real time do not use a very low
`scan_frequency` but adjust `close_inactive` so the file handler stays open and
constantly polls your files.

The default setting is 10s.

[float]
[id="{beatname_lc}-input-{type}-scan-sort"]
===== `scan.sort`

experimental[]

If you specify a value other than the empty string for this setting you can
determine whether to use ascending or descending order using `scan.order`.
Possible values are `modtime` and `filename`. To sort by file modification time,
use `modtime`, otherwise use `filename`. Leave this option empty to disable it.

If you specify a value for this setting, you can use `scan.order` to configure
whether files are scanned in ascending or descending order.

The default setting is disabled.

[float]
[id="{beatname_lc}-input-{type}-scan-order"]
===== `scan.order`

experimental[]

Specifies whether to use ascending or descending order when `scan.sort` is set to a value other than none. Possible values are `asc` or `desc`.

The default setting is `asc`.

[float]
===== `tail_files`

If this option is set to true, {beatname_uc} starts reading new files at the end
of each file instead of the beginning. When this option is used in combination
with log rotation, it's possible that the first log entries in a new file might
be skipped. The default setting is false.

This option applies to files that {beatname_uc} has not already processed. If
you ran {beatname_uc} previously and the state of the file was already
persisted, `tail_files` will not apply. Harvesting will continue at the previous
offset. To apply `tail_files` to all files, you must stop {beatname_uc} and
remove the registry file. Be aware that doing this removes ALL previous states.

NOTE: You can use this setting to avoid indexing old log lines when you run
{beatname_uc} on a set of log files for the first time. After the first run, we
recommend disabling this option, or you risk losing lines during file rotation.

[float]
===== `symlinks`

The `symlinks` option allows {beatname_uc} to harvest symlinks in addition to
regular files. When harvesting symlinks, {beatname_uc} opens and reads the
original file even though it reports the path of the symlink.

When you configure a symlink for harvesting, make sure the original path is
excluded. If a single input is configured to harvest both the symlink and
the original file, {beatname_uc} will detect the problem and only process the
first file it finds. However, if two different inputs are configured (one
to read the symlink and the other the original path), both paths will be
harvested, causing {beatname_uc} to send duplicate data and the inputs to
overwrite each other's state.

The `symlinks` option can be useful if symlinks to the log files have additional
metadata in the file name, and you want to process the metadata in Logstash.
This is, for example, the case for Kubernetes log files.

Because this option may lead to data loss, it is disabled by default.

[float]
===== `backoff`

The backoff options specify how aggressively {beatname_uc} crawls open files for
updates. You can use the default values in most cases.

The `backoff` option defines how long {beatname_uc} waits before checking a file
again after EOF is reached. The default is 1s, which means the file is checked
every second if new lines were added. This enables near real-time crawling.
Every time a new line appears in the file, the `backoff` value is reset to the
initial value. The default is 1s.

[float]
===== `max_backoff`

The maximum time for {beatname_uc} to wait before checking a file again after
EOF is reached. After having backed off multiple times from checking the file,
the wait time will never exceed `max_backoff` regardless of what is specified
for  `backoff_factor`. Because it takes a maximum of 10s to read a new line,
specifying 10s for `max_backoff` means that, at the worst, a new line could be
added to the log file if {beatname_uc} has backed off multiple times. The
default is 10s.

Requirement: Set `max_backoff` to be greater than or equal to `backoff` and
less than or equal to `scan_frequency` (`backoff <= max_backoff <= scan_frequency`).
If `max_backoff` needs to be higher, it is recommended to close the file handler
instead and let {beatname_uc} pick up the file again.

[float]
===== `backoff_factor`

This option specifies how fast the waiting time is increased. The bigger the
backoff factor, the faster the `max_backoff` value is reached. The backoff
factor increments exponentially. The minimum value allowed is 1. If this value
is set to 1, the backoff algorithm is disabled, and the `backoff` value is used
for waiting for new lines. The `backoff` value will be multiplied each time with
the `backoff_factor` until `max_backoff` is reached. The default is 2.

[float]
[id="{beatname_lc}-input-{type}-harvester-limit"]
===== `harvester_limit`

The `harvester_limit` option limits the number of harvesters that are started in
parallel for one input. This directly relates to the maximum number of file
handlers that are opened. The default for `harvester_limit` is 0, which means
there is no limit. This configuration is useful if the number of files to be
harvested exceeds the open file handler limit of the operating system.

Setting a limit on the number of harvesters means that potentially not all files
are opened in parallel. Therefore we recommended that you use this option in
combination with the `close_*` options to make sure harvesters are stopped more
often so that new files can be picked up.

Currently if a new harvester can be started again, the harvester is picked
randomly. This means it's possible that the harvester for a file that was just
closed and then updated again might be started instead of the harvester for a
file that hasn't been harvested for a longer period of time.

This configuration option applies per input. You can use this option to
indirectly set higher priorities on certain inputs by assigning a higher
limit of harvesters.