The strings
plugin maps certain go string functions onto measurement, tag, and field values. Values can be modified in place or stored in another key.
Implemented functions are:
- lowercase
- uppercase
- trim
- trim_left
- trim_right
- trim_prefix
- trim_suffix
- replace
- left
Please note that in this implementation these are processed in the order that they appear above.
Specify the measurement
, tag
, tag_key
, field
, or field_key
that you want processed in each section and optionally a dest
if you want the result stored in a new tag or field. You can specify lots of transformations on data with a single strings processor.
If you'd like to apply the change to every tag
, tag_key
, field
, field_key
, or measurement
, use the value "*"
for each respective field. Note that the dest
field will be ignored if "*"
is used.
If you'd like to apply multiple processings to the same tag_key
or field_key
, note the process order stated above. See Example 2 for an example.
[[processors.strings]]
## Convert a field value to lowercase and store in a new field
# [[processors.strings.lowercase]]
# field = "uri_stem"
# dest = "uri_stem_normalised"
## Convert a tag value to uppercase
# [[processors.strings.uppercase]]
# tag = "method"
## Trim leading and trailing whitespace using the default cutset
# [[processors.strings.trim]]
# field = "message"
## Trim leading characters in cutset
# [[processors.strings.trim_left]]
# field = "message"
# cutset = "\t"
## Trim trailing characters in cutset
# [[processors.strings.trim_right]]
# field = "message"
# cutset = "\r\n"
## Trim the given prefix from the field
# [[processors.strings.trim_prefix]]
# field = "my_value"
# prefix = "my_"
## Trim the given suffix from the field
# [[processors.strings.trim_suffix]]
# field = "read_count"
# suffix = "_count"
## Replace all non-overlapping instances of old with new
# [[processors.strings.replace]]
# measurement = "*"
# old = ":"
# new = "_"
## Trims strings based on width
# [[processors.strings.left]]
# field = "message"
# width = 10
The trim
, trim_left
, and trim_right
functions take an optional parameter: cutset
. This value is a string containing the characters to remove from the value.
The trim_prefix
and trim_suffix
functions remote the given prefix
or suffix
respectively from the string.
The replace
function does a substring replacement across the entire
string to allow for different conventions between various input and output
plugins. Some example usages are eliminating disallowed characters in
field names or replacing separators between different separators.
Can also be used to eliminate unneeded chars that were in metrics.
If the entire name would be deleted, it will refuse to perform
the operation and keep the old name.
Config
[[processors.strings]]
[[processors.strings.lowercase]]
tag = "uri_stem"
[[processors.strings.trim_prefix]]
tag = "uri_stem"
prefix = "/api/"
[[processors.strings.uppercase]]
field = "cs-host"
dest = "cs-host_normalised"
Input
iis_log,method=get,uri_stem=/API/HealthCheck cs-host="MIXEDCASE_host",http_version=1.1 1519652321000000000
Output
iis_log,method=get,uri_stem=healthcheck cs-host="MIXEDCASE_host",http_version=1.1,cs-host_normalised="MIXEDCASE_HOST" 1519652321000000000
Config
[[processors.strings]]
[[processors.strings.lowercase]]
tag_key = "URI-Stem"
[[processors.strings.replace]]
tag_key = "uri-stem"
old = "-"
new = "_"
Input
iis_log,URI-Stem=/API/HealthCheck http_version=1.1 1519652321000000000
Output
iis_log,uri_stem=/API/HealthCheck http_version=1.1 1519652321000000000