# Regex Processor Plugin The `regex` plugin transforms tag and field values with regex pattern. If `result_key` parameter is present, it can produce new tags and fields from existing ones. ### Configuration: ```toml [[processors.regex]] namepass = ["nginx_requests"] # Tag and field conversions defined in a separate sub-tables [[processors.regex.tags]] ## Tag to change key = "resp_code" ## Regular expression to match on a tag value pattern = "^(\\d)\\d\\d$" ## Matches of the pattern will be replaced with this string. Use ${1} ## notation to use the text of the first submatch. replacement = "${1}xx" [[processors.regex.fields]] ## Field to change key = "request" ## All the power of the Go regular expressions available here ## For example, named subgroups pattern = "^/api(?P/[\\w/]+)\\S*" replacement = "${method}" ## If result_key is present, a new field will be created ## instead of changing existing field result_key = "method" # Multiple conversions may be applied for one field sequentially # Let's extract one more value [[processors.regex.fields]] key = "request" pattern = ".*category=(\\w+).*" replacement = "${1}" result_key = "search_category" ``` ### Tags: No tags are applied by this processor. ### Example Output: ``` nginx_requests,verb=GET,resp_code=2xx request="/api/search/?category=plugins&q=regex&sort=asc",method="/search/",search_category="plugins",referrer="-",ident="-",http_version=1.1,agent="UserAgent",client_ip="127.0.0.1",auth="-",resp_bytes=270i 1519652321000000000 ```