--- title: "template | Grafana Enterprise Logs documentation" description: "template stage The template stage is a transform stage that lets use manipulate the values in the extracted map using Go’s template syntax. The template stage is primarily useful for manipulating data from other stages before setting them as labels, such as to replace spaces with underscores or converting an uppercase string into a lowercase one. template can also be used to construct messages with multiple keys." --- > For a curated documentation index, see [llms.txt](/llms.txt). For the complete documentation index, see [llms-full.txt](/llms-full.txt). # `template` stage The `template` stage is a transform stage that lets use manipulate the values in the extracted map using [Go’s template syntax](https://golang.org/pkg/text/template/). The `template` stage is primarily useful for manipulating data from other stages before setting them as labels, such as to replace spaces with underscores or converting an uppercase string into a lowercase one. `template` can also be used to construct messages with multiple keys. The template stage can also create new keys in the extracted map. ## Schema YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy ```yaml template: # Name from extracted data to parse. If key in extract data doesn't exist, an # entry for it will be created. source: # Go template string to use. In additional to normal template # functions, ToLower, ToUpper, Replace, Trim, TrimLeft, TrimRight, # TrimPrefix, TrimSuffix, and TrimSpace are available as functions. template: ``` ## Examples YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy ```yaml - template: source: new_key template: 'hello world!' ``` Assuming no data has been added to the extracted map yet, this stage will first add `new_key` with a blank value into the extracted map. Then its value will be set to `hello world!`. YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy ```yaml - template: source: app template: '{{ .Value }}_some_suffix' ``` This pipeline takes the value of the `app` key in the existing extracted map and appends `_some_suffix` to its value. For example, if the extracted map had a key of `app` and a value of `loki`, this stage would modify the value from `loki` to `loki_some_suffix`. YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy ```yaml - template: source: app template: '{{ ToLower .Value }}' ``` This pipeline takes the current value of `app` from the extracted map and converts its value to be all lowercase. For example, if the extracted map contained `app` with a value of `LOKI`, this pipeline would change its value to `loki`. YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy ```yaml - template: source: output_msg template: '{{ .level }} for app {{ ToUpper .app }}' ``` This pipeline takes the current value of `level` and `app` from the extracted map and a new key `output_msg` will be added to extracted map with evaluated template. For example, if the extracted map contained `app` with a value of `loki`, this pipeline would change its value to `LOKI`. Assuming value of `level` is `warn`. A new key `output_msg` will be added to extracted map with value `warn for app LOKI`. Any previously extracted keys can be used in `template`. All extracted keys are available for `template` to expand. YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy ```yaml - template: source: app template: '{{ .level }} for app {{ ToUpper .Value }} in module {{.module}}' ``` This pipeline takes the current value of `level`, `app` and `module` from the extracted map and converts value of `app` to the evaluated template. For example, if the extracted map contained `app` with a value of `loki`, this pipeline would change its value to `LOKI`. Assuming value of `level` is `warn` and value of `module` is `test`. Pipeline will change the value of `app` to `warn for app LOKI in module test`. Any previously extracted keys can be used in `template`. All extracted keys are available for `template` to expand. Also, if source is available it can be referred as `.Value` in `template`. Here, `app` is provided as `source`. So, it can be referred as `.Value` in `template`. YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy ```yaml - template: source: app template: '{{ Replace .Value "loki" "blokey" 1 }}' ``` The template here uses Go’s [`string.Replace` function](https://golang.org/pkg/strings/#Replace). When the template executes, the entire contents of the `app` key from the extracted map will have at most `1` instance of `loki` changed to `blokey`. A special key named `Entry` can be used to reference the current line, this can be useful when you need to append/prepend the log line. YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy ```yaml - template: source: message template: '{{.app }}: {{ .Entry }}' - output: source: message ``` The snippet above will for instance prepend the log line with the application name. ## Supported Functions > All [sprig functions](http://masterminds.github.io/sprig/) have been added to the template stage in Loki 2.3(along with function described below). ### ToLower & ToUpper ToLower and ToUpper convert the entire string respectively to lowercase and uppercase. Examples: YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy ```yaml - template: source: out template: '{{ ToLower .app }}' ``` YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy ```yaml - template: source: out template: '{{ .app | ToUpper }}' ``` ### Replace `Replace` returns a copy of the string s with the first n non-overlapping instances of old replaced by new. If old is empty, it matches at the beginning of the string and after each UTF-8 sequence, yielding up to k+1 replacements for a k-rune string. If n < 0, there is no limit on the number of replacements. The example below will replace the first two words `loki` by `Loki`. YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy ```yaml - template: source: output template: '{{ Replace .Value "loki" "Loki" 2 }}' ``` ### Trim `Trim` returns a slice of the string s with all leading and trailing Unicode code points contained in cutset removed. `TrimLeft` and `TrimRight` are the same as `Trim` except that it respectively trim only leading and trailing characters. YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy ```yaml - template: source: output template: '{{ Trim .Value ",. " }}' ``` `TrimSpace` TrimSpace returns a slice of the string s, with all leading and trailing white space removed, as defined by Unicode. YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy ```yaml - template: source: output template: '{{ TrimSpace .Value }}' ``` `TrimPrefix` and `TrimSuffix` will trim respectively the prefix or suffix supplied. YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy ```yaml - template: source: output template: '{{ TrimPrefix .Value "--" }}' ``` ### Regex `regexReplaceAll` returns a copy of the input string, replacing matches of the Regexp with the replacement string replacement. Inside string replacement, $ signs are interpreted as in Expand, so for instance $1 represents the text of the first submatch YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy ```yaml - template: source: output template: '{{ regexReplaceAll "(a*)bc" .Value "${1}a" }}' ``` `regexReplaceAllLiteral` returns a copy of the input string, replacing matches of the Regexp with the replacement string replacement The replacement string is substituted directly, without using Expand. YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy ```yaml - template: source: output template: '{{ regexReplaceAllLiteral "(ts=)" .Value "timestamp=" }}' ``` ### Hash and Sha2Hash `Hash` returns a Sha3\_256 hash of the string, represented as a hexadecimal number of 64 digits. You can use it to obfuscate sensitive data / PII in the logs. It requires a (fixed) salt value, to add complexity to low input domains (e.g. all possible Social Security Numbers). YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy ```yaml - template: source: output template: '{{ Hash .Value "salt" }}' ``` Alternatively, you can use `Sha2Hash` for calculating the Sha2\_256 of the string. Sha2\_256 is faster and requires less CPU than Sha3\_256, however it is less secure. We recommend using `Hash` as it has a stronger hashing algorithm which we plan to keep strong over time without requiring client config changes. YAML ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy ```yaml - template: source: output template: '{{ Sha2Hash .Value "salt" }}' ```