LogQL on Grafana Labs

Log queries

Mon, 14 Apr 2025 21:05:47 +0000

Log queries

All LogQL queries contain a log stream selector.

Optionally, the log stream selector can be followed by a log pipeline. A log pipeline is a set of stage expressions that are chained together and applied to the selected log streams. Each expression can filter out, parse, or mutate log lines and their respective labels.

The following example shows a full log query in action:

{container="query-frontend",namespace="loki-dev"} |= "metrics.go" | logfmt | duration > 10s and throughput_mb < 500

The query is composed of:

a log stream selector {container="query-frontend",namespace="loki-dev"} which targets the query-frontend container in the loki-dev namespace.
a log pipeline |= "metrics.go" | logfmt | duration > 10s and throughput_mb < 500 which will filter out log that contains the word metrics.go, then parses each log line to extract more labels and filter with them.

To avoid escaping special characters you can use the `(backtick) instead of " when quoting strings. For example `\w+` is the same as "\\w+". This is specially useful when writing a regular expression which contains multiple backslashes that require escaping.

Log stream selector

The stream selector determines which log streams to include in a query’s results. A log stream is a unique source of log content, such as a file. A more granular log stream selector then reduces the number of searched streams to a manageable volume. This means that the labels passed to the log stream selector will affect the relative performance of the query’s execution.

The log stream selector is specified by one or more comma-separated key-value pairs. Each key is a log label and each value is that label’s value. Curly braces ({ and }) delimit the stream selector.

Consider this stream selector:

{app="mysql",name="mysql-backup"}

All log streams that have both a label of app whose value is mysql and a label of name whose value is mysql-backup will be included in the query results. A stream may contain other pairs of labels and values, but only the specified pairs within the stream selector are used to determine which streams will be included within the query results.

The same rules that apply for Prometheus Label Selectors apply for Grafana Loki log stream selectors.

The = operator after the label name is a label matching operator. The following label matching operators are supported:

=: exactly equal
!=: not equal
=~: regex matches
!~: regex does not match

Regex log stream examples:

{name =~ "mysql.+"}
{name !~ "mysql.+"}
{name !~ `mysql-\d+`}

Note: The =~ regex operator is fully anchored, meaning regex must match against the entire string, including newlines. The regex . character does not match newlines by default. If you want the regex dot character to match newlines you can use the single-line flag, like so: (?s)search_term.+ matches search_term\n.

Log pipeline

A log pipeline can be appended to a log stream selector to further process and filter log streams. It is composed of a set of expressions. Each expression is executed in left to right sequence for each log line. If an expression filters out a log line, the pipeline will stop processing the current log line and start processing the next log line.

Some expressions can mutate the log content and respective labels, which will be then be available for further filtering and processing in subsequent expressions. An example that mutates is the expression

| line_format "{{.status_code}}"

Log pipeline expressions fall into one of three categories:

Filtering expressions: line filter expressions and label filter expressions
Parsing expressions
Formatting expressions: line format expressions and label format expressions

Line filter expression

The line filter expression does a distributed grep over the aggregated logs from the matching log streams. It searches the contents of the log line, discarding those lines that do not match the case sensitive expression.

Each line filter expression has a filter operator followed by text or a regular expression. These filter operators are supported:

|=: Log line contains string
!=: Log line does not contain string
|~: Log line contains a match to the regular expression
!~: Log line does not contain a match to the regular expression

Line filter expression examples:

Keep log lines that have the substring “error”:
```
|= "error"
```
A complete query using this example:
```
{job="mysql"} |= "error"
```
Discard log lines that have the substring “kafka.server:type=ReplicaManager”:
```
!= "kafka.server:type=ReplicaManager"
```
A complete query using this example:
```
{instance=~"kafka-[23]",name="kafka"} != "kafka.server:type=ReplicaManager"
```
Keep log lines that contain a substring that starts with tsdb-ops and ends with io:2003. A complete query with a regular expression:
```
{name="kafka"} |~ "tsdb-ops.*io:2003"
```
Keep log lines that contain a substring that starts with error=, and is followed by 1 or more word characters. A complete query with a regular expression:
```
{name="cassandra"} |~  `error=\w+`
```

Filter operators can be chained. Filters are applied sequentially. Query results will have satisfied every filter. This complete query example will give results that include the string error, and do not include the string timeout.

{job="mysql"} |= "error" != "timeout"

When using |~ and !~, Go (as in Golang) RE2 syntax regex may be used. The matching is case-sensitive by default. Switch to case-insensitive matching by prefixing the regular expression with (?i).

While line filter expressions could be placed anywhere within a log pipeline, it is almost always better to have them at the beginning. Placing them at the beginning improves the performance of the query, as it only does further processing when a line matches. For example, while the results will be the same, the query specified with

{job="mysql"} |= "error" | json | line_format "{{.err}}"

will always run faster than

{job="mysql"} | json | line_format "{{.message}}" |= "error"

Line filter expressions are the fastest way to filter logs once the log stream selectors have been applied.

Line filter expressions have support matching IP addresses. See Matching IP addresses for details.

Label filter expression

Label filter expression allows filtering log line using their original and extracted labels. It can contain multiple predicates.

A predicate contains a label identifier, an operation and a value to compare the label with.

For example with cluster="namespace" the cluster is the label identifier, the operation is = and the value is “namespace”. The label identifier is always on the right side of the operation.

We support multiple value types which are automatically inferred from the query input.

String is double quoted or backticked such as "200" or `us-central1`.
Duration is a sequence of decimal numbers, each with optional fraction and a unit suffix, such as “300ms”, “1.5h” or “2h45m”. Valid time units are “ns”, “us” (or “µs”), “ms”, “s”, “m”, “h”.
Number are floating-point number (64bits), such as250, 89.923.
Bytes is a sequence of decimal numbers, each with optional fraction and a unit suffix, such as “42MB”, “1.5Kib” or “20b”. Valid bytes units are “b”, “kib”, “kb”, “mib”, “mb”, “gib”, “gb”, “tib”, “tb”, “pib”, “pb”, “eib”, “eb”.

String type work exactly like Prometheus label matchers use in log stream selector. This means you can use the same operations (=,!=,=~,!~).

The string type is the only one that can filter out a log line with a label __error__.

Using Duration, Number and Bytes will convert the label value prior to comparision and support the following comparators:

== or = for equality.
!= for inequality.
> and >= for greater than and greater than or equal.
< and <= for lesser than and lesser than or equal.

For instance, logfmt | duration > 1m and bytes_consumed > 20MB

If the conversion of the label value fails, the log line is not filtered and an __error__ label is added. To filters those errors see the pipeline errors section.

You can chain multiple predicates using and and or which respectively express the and and or binary operations. and can be equivalently expressed by a comma, a space or another pipe. Label filters can be place anywhere in a log pipeline.

This means that all the following expressions are equivalent:

| duration >= 20ms or size == 20kb and method!~"2.."
| duration >= 20ms or size == 20kb | method!~"2.."
| duration >= 20ms or size == 20kb , method!~"2.."
| duration >= 20ms or size == 20kb  method!~"2.."

By default the precedence of multiple predicates is right to left. You can wrap predicates with parenthesis to force a different precedence left to right.

For example the following are equivalent.

| duration >= 20ms or method="GET" and size <= 20KB
| ((duration >= 20ms or method="GET") and size <= 20KB)

It will evaluate first duration >= 20ms or method="GET". To evaluate first method="GET" and size <= 20KB, make sure to use proper parenthesis as shown below.

| duration >= 20ms or (method="GET" and size <= 20KB)

Label filter expressions are the only expression allowed after the unwrap expression. This is mainly to allow filtering errors from the metric extraction.

Label filter expressions have support matching IP addresses. See Matching IP addresses for details.

Parser expression

Parser expression can parse and extract labels from the log content. Those extracted labels can then be used for filtering using label filter expressions or for metric aggregations.

Extracted label keys are automatically sanitized by all parsers, to follow Prometheus metric name convention.(They can only contain ASCII letters and digits, as well as underscores and colons. They cannot start with a digit.)

For instance, the pipeline | json will produce the following mapping:

{ "a.b": {c: "d"}, e: "f" }

{a_b_c="d", e="f"}

In case of errors, for instance if the line is not in the expected format, the log line won’t be filtered but instead will get a new __error__ label added.

If an extracted label key name already exists in the original log stream, the extracted label key will be suffixed with the _extracted keyword to make the distinction between the two labels. You can forcefully override the original label using a label formatter expression. However if an extracted key appears twice, only the latest label value will be kept.

Loki supports JSON, logfmt, pattern, regexp and unpack parsers.

It’s easier to use the predefined parsers json and logfmt when you can. If you can’t, the pattern and regexp parsers can be used for log lines with an unusual structure. The pattern parser is easier and faster to write; it also outperforms the regexp parser. Multiple parsers can be used by a single log pipeline. This is useful for parsing complex logs. There are examples in Multiple parsers.

JSON

The json parser operates in two modes:

without parameters:

Adding | json to your pipeline will extract all json properties as labels if the log line is a valid json document. Nested properties are flattened into label keys using the _ separator.

Note: Arrays are skipped.

For example the json parsers will extract from the following document:

{
    "protocol": "HTTP/2.0",
    "servers": ["129.0.1.1","10.2.1.3"],
    "request": {
        "time": "6.032",
        "method": "GET",
        "host": "foo.grafana.net",
        "size": "55",
        "headers": {
          "Accept": "*/*",
          "User-Agent": "curl/7.68.0"
        }
    },
    "response": {
        "status": 401,
        "size": "228",
        "latency_seconds": "6.031"
    }
}

The following list of labels:

"protocol" => "HTTP/2.0"
"request_time" => "6.032"
"request_method" => "GET"
"request_host" => "foo.grafana.net"
"request_size" => "55"
"response_status" => "401"
"response_size" => "228"
"response_latency_seconds" => "6.031"

with parameters:

Using | json label="expression", another="expression" in your pipeline will extract only the specified json fields to labels. You can specify one or more expressions in this way, the same as label_format; all expressions must be quoted.

Currently, we only support field access (my.field, my["field"]) and array access (list[0]), and any combination of these in any level of nesting (my.list[0]["field"]).

For example, | json first_server="servers[0]", ua="request.headers[\"User-Agent\"] will extract from the following document:
JSON
```
{
    "protocol": "HTTP/2.0",
    "servers": ["129.0.1.1","10.2.1.3"],
    "request": {
        "time": "6.032",
        "method": "GET",
        "host": "foo.grafana.net",
        "size": "55",
        "headers": {
          "Accept": "*/*",
          "User-Agent": "curl/7.68.0"
        }
    },
    "response": {
        "status": 401,
        "size": "228",
        "latency_seconds": "6.031"
    }
}
```
The following list of labels:
kv
```
"first_server" => "129.0.1.1"
"ua" => "curl/7.68.0"
```
If an array or an object returned by an expression, it will be assigned to the label in json format.

For example, | json server_list="servers", headers="request.headers" will extract:
kv
```
"server_list" => `["129.0.1.1","10.2.1.3"]`
"headers" => `{"Accept": "*/*", "User-Agent": "curl/7.68.0"}`
```
If the label to be extracted is same as the original JSON field, expression can be written as just | json <label>

For example, to extract servers fields as label, expression can be written as following

| json servers will extract:
kv
```
"servers" => `["129.0.1.1","10.2.1.3"]`
```
Note that | json servers is same as | json servers="servers"

logfmt

The logfmt parser can be added using the | logfmt and will extract all keys and values from the logfmt formatted log line.

For example the following log line:

at=info method=GET path=/ host=grafana.net fwd="124.133.124.161" service=8ms status=200

will get those labels extracted:

"at" => "info"
"method" => "GET"
"path" => "/"
"host" => "grafana.net"
"fwd" => "124.133.124.161"
"service" => "8ms"
"status" => "200"

Pattern

The pattern parser allows the explicit extraction of fields from log lines by defining a pattern expression (| pattern "<pattern-expression>"). The expression matches the structure of a log line.

Consider this NGINX log line.

0.191.12.2 - - [10/Jun/2021:09:14:29 +0000] "GET /api/plugins/versioncheck HTTP/1.1" 200 2 "-" "Go-http-client/2.0" "13.76.247.102, 34.120.177.193" "TLSv1.2" "US" ""

This log line can be parsed with the expression

<ip> - - <_> "<method> <uri> <_>" <status> <size> <_> "<agent>" <_>

to extract these fields:

"ip" => "0.191.12.2"
"method" => "GET"
"uri" => "/api/plugins/versioncheck"
"status" => "200"
"size" => "2"
"agent" => "Go-http-client/2.0"

A pattern expression is composed of captures and literals.

A capture is a field name delimited by the < and > characters. <example> defines the field name example. An unnamed capture appears as <_>. The unnamed capture skips matched content.

Captures are matched from the line beginning or the previous set of literals, to the line end or the next set of literals. If a capture is not matched, the pattern parser will stop.

Literals can be any sequence of UTF-8 characters, including whitespace characters.

By default, a pattern expression is anchored at the start of the log line. If the expression starts with literals, then the log line must also start with the same set of literals. Use <_> at the beginning of the expression if you don’t want to anchor the expression at the start.

Consider the log line

level=debug ts=2021-06-10T09:24:13.472094048Z caller=logging.go:66 traceID=0568b66ad2d9294c msg="POST /loki/api/v1/push (204) 16.652862ms"

To match msg=", use the expression:

<_> msg="<method> <path> (<status>) <latency>"

A pattern expression is invalid if

It does not contain any named capture.
It contains two consecutive captures not separated by whitespace characters.

Regular expression

Unlike the logfmt and json, which extract implicitly all values and takes no parameters, the regexp parser takes a single parameter | regexp "<re>" which is the regular expression using the Golang RE2 syntax.

The regular expression must contain a least one named sub-match (e.g (?P<name>re)), each sub-match will extract a different label.

For example the parser | regexp "(?P<method>\\w+) (?P<path>[\\w|/]+) \$(?P<status>\\d+?)\$ (?P<duration>.*)" will extract from the following line:

POST /api/prom/api/v1/query_range (200) 1.5s

those labels:

"method" => "POST"
"path" => "/api/prom/api/v1/query_range"
"status" => "200"
"duration" => "1.5s"

unpack

The unpack parser parses a JSON log line, unpacking all embedded labels from Promtail’s pack stage. A special property _entry will also be used to replace the original log line.

For example, using | unpack with the log line:

{
  "container": "myapp",
  "pod": "pod-3223f",
  "_entry": "original log message"
}

extracts the container and pod labels; it sets original log message as the new log line.

You can combine the unpack and json parsers (or any other parsers) if the original embedded log line is of a specific format.

Line format expression

The line format expression can rewrite the log line content by using the text/template format. It takes a single string parameter | line_format "{{.label_name}}", which is the template format. All labels are injected variables into the template and are available to use with the {{.label_name}} notation.

For example the following expression:

{container="frontend"} | logfmt | line_format "{{.query}} {{.duration}}"

Will extract and rewrite the log line to only contains the query and the duration of a request.

You can use double quoted string for the template or backticks `{{.label_name}}` to avoid the need to escape special characters.

line_format also supports math functions. Example:

If we have the following labels ip=1.1.1.1, status=200 and duration=3000(ms), we can divide the duration by 1000 to get the value in seconds.

{container="frontend"} | logfmt | line_format "{{.ip}} {{.status}} {{div .duration 1000}}"

The above query will give us the line as 1.1.1.1 200 3

See template functions to learn about available functions in the template format.

Labels format expression

The | label_format expression can rename, modify or add labels. It takes as parameter a comma separated list of equality operations, enabling multiple operations at once.

When both side are label identifiers, for example dst=src, the operation will rename the src label into dst.

The right side can alternatively be a template string (double quoted or backtick), for example dst="{{.status}} {{.query}}", in which case the dst label value is replaced by the result of the text/template evaluation. This is the same template engine as the | line_format expression, which means labels are available as variables and you can use the same list of functions.

In both cases, if the destination label doesn’t exist, then a new one is created.

The renaming form dst=src will drop the src label after remapping it to the dst label. However, the template form will preserve the referenced labels, such that dst="{{.src}}" results in both dst and src having the same value.

A single label name can only appear once per expression. This means | label_format foo=bar,foo="new" is not allowed but you can use two expressions for the desired effect: | label_format foo=bar | label_format foo="new"

Log queries examples

Multiple filtering

Filtering should be done first using label matchers, then line filters (when possible) and finally using label filters. The following query demonstrate this.

{cluster="ops-tools1", namespace="loki-dev", job="loki-dev/query-frontend"} |= "metrics.go" !="out of order" | logfmt | duration > 30s or status_code!="200"

Multiple parsers

To extract the method and the path of the following logfmt log line:

level=debug ts=2020-10-02T10:10:42.092268913Z caller=logging.go:66 traceID=a9d4d8a928d8db1 msg="POST /api/prom/api/v1/query_range (200) 1.5s"

You can use multiple parsers (logfmt and regexp) like this.

{job="loki-ops/query-frontend"} | logfmt | line_format "{{.msg}}" | regexp "(?P<method>\\w+) (?P<path>[\\w|/]+) \\((?P<status>\\d+?)\\) (?P<duration>.*)"

This is possible because the | line_format reformats the log line to become POST /api/prom/api/v1/query_range (200) 1.5s which can then be parsed with the | regexp ... parser.

Formatting

The following query shows how you can reformat a log line to make it easier to read on screen.

{cluster="ops-tools1", name="querier", namespace="loki-dev"}
  |= "metrics.go" != "loki-canary"
  | logfmt
  | query != ""
  | label_format query="{{ Replace .query \"\\n\" \"\" -1 }}"
  | line_format "{{ .ts}}\t{{.duration}}\ttraceID = {{.traceID}}\t{{ printf \"%-100.100s\" .query }} "

Label formatting is used to sanitize the query while the line format reduce the amount of information and creates a tabular output.

For these given log lines:

level=info ts=2020-10-23T20:32:18.094668233Z caller=metrics.go:81 org_id=29 traceID=1980d41501b57b68 latency=fast query="{cluster=\"ops-tools1\", job=\"loki-ops/query-frontend\"} |= \"query_range\"" query_type=filter range_type=range length=15m0s step=7s duration=650.22401ms status=200 throughput_mb=1.529717 total_bytes_mb=0.994659
level=info ts=2020-10-23T20:32:18.068866235Z caller=metrics.go:81 org_id=29 traceID=1980d41501b57b68 latency=fast query="{cluster=\"ops-tools1\", job=\"loki-ops/query-frontend\"} |= \"query_range\"" query_type=filter range_type=range length=15m0s step=7s duration=624.008132ms status=200 throughput_mb=0.693449 total_bytes_mb=0.432718

The result would be:

2020-10-23T20:32:18.094668233Z	650.22401ms	    traceID = 1980d41501b57b68	{cluster="ops-tools1", job="loki-ops/query-frontend"} |= "query_range"
2020-10-23T20:32:18.068866235Z	624.008132ms	traceID = 1980d41501b57b68	{cluster="ops-tools1", job="loki-ops/query-frontend"} |= "query_range"

Metric queries

Tue, 16 Jul 2024 15:42:20 +0000

Metric queries

Metric queries extend log queries by applying a function to log query results. This powerful feature creates metrics from logs.

Metric queries can be used to calculate the rate of error messages or the top N log sources with the greatest quantity of logs over the last 3 hours.

Combined with parsers, metric queries can also be used to calculate metrics from a sample value within the log line, such as latency or request size. All labels, including extracted ones, will be available for aggregations and generation of new series.

Range Vector aggregation

LogQL shares the range vector concept of Prometheus. In Grafana Loki, the selected range of samples is a range of selected log or label values.

The aggregation is applied over a time duration. Loki defines Time Durations with the same syntax as Prometheus.

Loki supports two types of range vector aggregations: log range aggregations and unwrapped range aggregations.

Log range aggregations

A log range aggregation is a query followed by a duration. A function is applied to aggregate the query over the duration. The duration can be placed after the log stream selector or at end of the log pipeline.

The functions:

rate(log-range): calculates the number of entries per second
count_over_time(log-range): counts the entries for each log stream within the given range.
bytes_rate(log-range): calculates the number of bytes per second for each stream.
bytes_over_time(log-range): counts the amount of bytes used by each log stream for a given range.
absent_over_time(log-range): returns an empty vector if the range vector passed to it has any elements and a 1-element vector with the value 1 if the range vector passed to it has no elements. (absent_over_time is useful for alerting on when no time series and logs stream exist for label combination for a certain amount of time.)

Examples:

Count all the log lines within the last five minutes for the MySQL job.
logql
```
count_over_time({job="mysql"}[5m])
```
This aggregation includes filters and parsers. It returns the per-second rate of all non-timeout errors within the last minutes per host for the MySQL job and only includes errors whose duration is above ten seconds.
logql
```
sum by (host) (rate({job="mysql"} |= "error" != "timeout" | json | duration > 10s [1m]))
```

Unwrapped range aggregations

Unwrapped ranges uses extracted labels as sample values instead of log lines. However to select which label will be used within the aggregation, the log query must end with an unwrap expression and optionally a label filter expression to discard errors.

The unwrap expression is noted | unwrap label_identifier where the label identifier is the label name to use for extracting sample values.

Since label values are string, by default a conversion into a float (64bits) will be attempted, in case of failure the __error__ label is added to the sample. Optionally the label identifier can be wrapped by a conversion function | unwrap <function>(label_identifier), which will attempt to convert the label value from a specific format.

We currently support the functions:

duration_seconds(label_identifier) (or its short equivalent duration) which will convert the label value in seconds from the go duration format (e.g 5m, 24s30ms).
bytes(label_identifier) which will convert the label value to raw bytes applying the bytes unit (e.g. 5 MiB, 3k, 1G).

Supported function for operating over unwrapped ranges are:

rate(unwrapped-range): calculates per second rate of the sum of all values in the specified interval.
rate_counter(unwrapped-range): calculates per second rate of the values in the specified interval and treating them as “counter metric”
sum_over_time(unwrapped-range): the sum of all values in the specified interval.
avg_over_time(unwrapped-range): the average value of all points in the specified interval.
max_over_time(unwrapped-range): the maximum value of all points in the specified interval.
min_over_time(unwrapped-range): the minimum value of all points in the specified interval
first_over_time(unwrapped-range): the first value of all points in the specified interval
last_over_time(unwrapped-range): the last value of all points in the specified interval
stdvar_over_time(unwrapped-range): the population standard variance of the values in the specified interval.
stddev_over_time(unwrapped-range): the population standard deviation of the values in the specified interval.
quantile_over_time(scalar,unwrapped-range): the φ-quantile (0 ≤ φ ≤ 1) of the values in the specified interval.
absent_over_time(unwrapped-range): returns an empty vector if the range vector passed to it has any elements and a 1-element vector with the value 1 if the range vector passed to it has no elements. (absent_over_time is useful for alerting on when no time series and logs stream exist for label combination for a certain amount of time.)

Except for sum_over_time,absent_over_time and rate, unwrapped range aggregations support grouping.

<aggr-op>([parameter,] <unwrapped-range>) [without|by (<label list>)]

Which can be used to aggregate over distinct labels dimensions by including a without or by clause.

without removes the listed labels from the result vector, while all other labels are preserved the output. by does the opposite and drops labels that are not listed in the by clause, even if their label values are identical between all elements of the vector.

Unwrapped examples

quantile_over_time(0.99,
  {cluster="ops-tools1",container="ingress-nginx"}
    | json
    | __error__ = ""
    | unwrap request_time [1m]) by (path)

This example calculates the p99 of the nginx-ingress latency by path.

sum by (org_id) (
  sum_over_time(
  {cluster="ops-tools1",container="loki-dev"}
      |= "metrics.go"
      | logfmt
      | unwrap bytes_processed [1m])
  )

This calculates the amount of bytes processed per organization ID.

Built-in aggregation operators

Like PromQL, LogQL supports a subset of built-in aggregation operators that can be used to aggregate the element of a single vector, resulting in a new vector of fewer elements but with aggregated values:

sum: Calculate sum over labels
avg: Calculate the average over labels
min: Select minimum over labels
max: Select maximum over labels
stddev: Calculate the population standard deviation over labels
stdvar: Calculate the population standard variance over labels
count: Count number of elements in the vector
topk: Select largest k elements by sample value
bottomk: Select smallest k elements by sample value

The aggregation operators can either be used to aggregate over all label values or a set of distinct label values by including a without or a by clause:

<aggr-op>([parameter,] <vector expression>) [without|by (<label list>)]

parameter is required when using topk and bottomk. topk and bottomk are different from other aggregators in that a subset of the input samples, including the original labels, are returned in the result vector.

by and without are only used to group the input vector. The without clause removes the listed labels from the resulting vector, keeping all others. The by clause does the opposite, dropping labels that are not listed in the clause, even if their label values are identical between all elements of the vector.

Vector aggregation examples

Get the top 10 applications by the highest log throughput:

topk(10,sum(rate({region="us-east1"}[5m])) by (name))

Get the count of log lines for the last five minutes for a specified job, grouping by level:

sum(count_over_time({job="mysql"}[5m])) by (level)

Get the rate of HTTP GET requests to the /home endpoint for NGINX logs by region:

avg(rate(({job="nginx"} |= "GET" | json | path="/home")[10s])) by (region)

Template functions

Tue, 16 Jul 2024 15:42:20 +0000

Template functions

The text template format used in | line_format and | label_format support the usage of functions.

All labels are added as variables in the template engine. They can be referenced using they label name prefixed by a .(e.g .label_name). For example the following template will output the value of the path label:

{{ .path }}

Additionally you can also access the log line using the __line__ function.

You can take advantage of pipeline to join together multiple functions. In a chained pipeline, the result of each command is passed as the last argument of the following command.

Example:

{{ .path | replace " " "_" | trunc 5 | upper }}

line

This function returns the current log line.

Signature:

line() string

Examples:

"{{ __line__ | lower }}"
`{{ __line__ }}`

ToLower and ToUpper

This function converts the entire string to lowercase or uppercase.

Signatures:

ToLower(string) string
ToUpper(string) string

Examples:

"{{.request_method | ToLower}}"
"{{.request_method | ToUpper}}"
`{{ToUpper "This is a string" | ToLower}}`

Note: In Grafana Loki 2.1 you can also use respectively lower and upper shortcut, e.g {{.request_method | lower }}.

Replace string

Note: In Loki 2.1 replace (as opposed to Replace) is available with a different signature but easier to chain within pipeline.

Use this function to perform a simple string replacement.

Signature:

Replace(s, old, new string, n int) string

It takes four arguments:

s source string
old string to replace
new string to replace with
n the maximun amount of replacement (-1 for all)

Example:

`{{ Replace "This is a string" " " "-" -1 }}`

The results in This-is-a-string.

Trim, TrimLeft, TrimRight, and TrimSpace

Note: In Loki 2.1 trim, trimAll, trimSuffix and trimPrefix have been added with a different signature for better pipeline chaining.

Trim returns a slice of the string s with all leading and trailing Unicode code points contained in cutset removed.

Signature: Trim(value, cutset string) string

TrimLeft and TrimRight are the same as Trim except that it trims only leading and trailing characters respectively.

`{{ Trim .query ",. " }}`
`{{ TrimLeft .uri ":" }}`
`{{ TrimRight .path "/" }}`

TrimSpace TrimSpace returns string s with all leading and trailing white space removed, as defined by Unicode.

Signature: TrimSpace(value string) string

{{ TrimSpace .latency }}

TrimPrefix and TrimSuffix will trim respectively the prefix or suffix supplied.

Signature:

TrimPrefix(value string, prefix string) string
TrimSuffix(value string, suffix string) string

{{ TrimPrefix .path "/" }}

regexReplaceAll and regexReplaceAllLiteral

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 sub-match. See the golang Regexp.replaceAll documentation for more examples.

`{{ regexReplaceAll "(a*)bc" .some_label "${1}a" }}`

regexReplaceAllLiteral function returns a copy of the input string and replaces matches of the Regexp with the replacement string replacement. The replacement string is substituted directly, without using Expand.

`{{ regexReplaceAllLiteral "(ts=)" .timestamp "timestamp=" }}`

You can combine multiple functions using pipe. For example, to strip out spaces and make the request method in capital, you would write the following template: {{ .request_method | TrimSpace | ToUpper }}.

lower

Added in Loki 2.1

Use this function to convert to lower case.

Signature:

lower(string) string

Examples:

"{{ .request_method | lower }}"
`{{ lower  "HELLO"}}`

The last example will return hello.

upper

Added in Loki 2.1

Use this function to convert to upper case.

Signature:

upper(string) string

Examples:

"{{ .request_method | upper }}"
`{{ upper  "hello"}}`

This results in HELLO.

title

Note: Added in Loki 2.1.

Convert to title case.

Signature:

title(string) string

Examples:

"{{.request_method | title}}"
`{{ title "hello world"}}`

The last example will return Hello World.

trunc

Note: Added in Loki 2.1.

Truncate a string and add no suffix.

Signature:

trunc(count int,value string) string

Examples:

"{{ .path | trunc 2 }}"
`{{ trunc 5 "hello world"}}`   // output: hello
`{{ trunc -5 "hello world"}}`  // output: world

substr

Note: Added in Loki 2.1.

Get a substring from a string.

Signature:

substr(start int,end int,value string) string

If start is < 0, this calls value[:end]. If start is >= 0 and end < 0 or end bigger than s length, this calls value[start:] Otherwise, this calls value[start, end].

Examples:

"{{ .path | substr 2 5 }}"
`{{ substr 0 5 "hello world"}}`  // output: hello
`{{ substr 6 11 "hello world"}}` // output: world

replace

Note: Added in Loki 2.1.

This function performs simple string replacement.

Signature: replace(old string, new string, src string) string

It takes three arguments:

old string to replace
new string to replace with
src source string

Examples:

{{ .cluster | replace "-cluster" "" }}
{{ replace "hello" "world" "hello world" }}

The last example will return world world.

trim

Note: Added in Loki 2.1.

The trim function removes space from either side of a string.

Signature: trim(string) string

Examples:

{{ .ip | trim }}
{{ trim "   hello    " }} // output: hello

trimAll

Note: Added in Loki 2.1.

Use this function to remove given characters from the front or back of a string.

Signature: trimAll(chars string,src string) string

Examples:

{{ .path | trimAll "/" }}
{{ trimAll "$" "$5.00" }} // output: 5.00

trimSuffix

Note: Added in Loki 2.1.

Use this function to trim just the suffix from a string.

Signature: trimSuffix(suffix string, src string) string

Examples:

{{  .path | trimSuffix "/" }}
{{ trimSuffix "-" "hello-" }} // output: hello

trimPrefix

Note: Added in Loki 2.1.

Use this function to trim just the prefix from a string.

Signature: trimPrefix(suffix string, src string) string

Examples:

{{  .path | trimPrefix "/" }}
{{ trimPrefix "-" "-hello" }} // output: hello

indent

Note: Added in Loki 2.1.

The indent function indents every line in a given string to the specified indent width. This is useful when aligning multi-line strings.

Signature: indent(spaces int,src string) string

{{ indent 4 .query }}

This indents each line contained in the .query by four (4) spaces.

nindent

Note: Added in Loki 2.1.

The nindent function is the same as the indent function, but prepends a new line to the beginning of the string.

Signature: nindent(spaces int,src string) string

{{ nindent 4 .query }}

This will indent every line of text by 4 space characters and add a new line to the beginning.

repeat

Note: Added in Loki 2.1.

Use this function to repeat a string multiple times.

Signature: repeat(c int,value string) string

{{ repeat 3 "hello" }} // output: hellohellohello

contains

Note: Added in Loki 2.1.

Use this function to test to see if one string is contained inside of another.

Signature: contains(s string, src string) bool

Examples:

{{ if .err contains "ErrTimeout" }} timeout {{end}}
{{ if contains "he" "hello" }} yes {{end}}

hasPrefix and hasSuffix

Note: Added in Loki 2.1.

The hasPrefix and hasSuffix functions test whether a string has a given prefix or suffix.

Signatures:

hasPrefix(prefix string, src string) bool
hasSuffix(suffix string, src string) bool

Examples:

{{ if .err hasSuffix "Timeout" }} timeout {{end}}
{{ if hasPrefix "he" "hello" }} yes {{end}}

add

Note: Added in Loki 2.3.

Sum numbers. Supports multiple numbers

Signature: func(i ...interface{}) int64

{{ add 3 2 5 }} // output: 10

sub

Note: Added in Loki 2.3.

Subtract numbers.

Signature: func(a, b interface{}) int64

{{ sub 5 2 }} // output: 3

mul

Note: Added in Loki 2.3.

Mulitply numbers. Supports multiple numbers.

Signature: func(a interface{}, v ...interface{}) int64

{{ mul 5 2 3}} // output: 30

div

Note: Added in Loki 2.3.

Integer divide numbers.

Signature: func(a, b interface{}) int64

{{ div 10 2}} // output: 5

addf

Note: Added in Loki 2.3.

Sum numbers. Supports multiple numbers.

Signature: func(i ...interface{}) float64

{{ addf 3.5 2 5 }} // output: 10.5

subf

Note: Added in Loki 2.3.

Subtract numbers. Supports multiple numbers.

Signature: func(a interface{}, v ...interface{}) float64

{{ subf  5.5 2 1.5 }} // output: 2

mulf

Note: Added in Loki 2.3.

Mulitply numbers. Supports multiple numbers

Signature: func(a interface{}, v ...interface{}) float64

{{ mulf 5.5 2 2.5 }} // output: 27.5

divf

Note: Added in Loki 2.3.

Divide numbers. Supports multiple numbers.

Signature: func(a interface{}, v ...interface{}) float64

{{ divf 10 2 4}} // output: 1.25

mod

Note: Added in Loki 2.3.

Modulo wit mod.

Signature: func(a, b interface{}) int64

{{ mod 10 3}} // output: 1

max

Note: Added in Loki 2.3.

Return the largest of a series of integers:

Signature: max(a interface{}, i ...interface{}) int64

{{ max 1 2 3 }} //output 3

min

Note: Added in Loki 2.3.

Return the smallest of a series of integers.

Signature: min(a interface{}, i ...interface{}) int64

{{ max 1 2 3 }} //output 1

maxf

Note: Added in Loki 2.3.

Return the largest of a series of floats:

Signature: maxf(a interface{}, i ...interface{}) float64

{{ maxf 1 2.5 3 }} //output 3

minf

Note: Added in Loki 2.3.

Return the smallest of a series of floats.

Signature: minf(a interface{}, i ...interface{}) float64

{{ minf 1 2.5 3 }} //output 1.5

ceil

Note: Added in Loki 2.3.

Returns the greatest float value greater than or equal to input value

Signature: ceil(a interface{}) float64

{{ ceil 123.001 }} //output 124.0

floor

Note: Added in Loki 2.3.

Returns the greatest float value less than or equal to input value

Signature: floor(a interface{}) float64

{{ floor 123.9999 }} //output 123.0

round

Note: Added in Loki 2.3.

Returns a float value with the remainder rounded to the given number of digits after the decimal point.

Signature: round(a interface{}, p int, rOpt ...float64) float64

{{ round 123.555555 3 }} //output 123.556

We can also provide a roundOn number as third parameter

{{ round 123.88571428571 5 .2 }} //output 123.88572

With default roundOn of .5 the above value would be 123.88571

int

Note: Added in Loki 2.3.

Convert value to an int.

Signature: toInt(v interface{}) int

{{ "3" | int }} //output 3

float64

Note: Added in Loki 2.3.

Convert to a float64.

Signature: toFloat64(v interface{}) float64

{{ "3.5" | float64 }} //output 3.5

fromJson

Note: Added in Loki 2.3.

fromJson decodes a JSON document into a structure. If the input cannot be decoded as JSON the function will return an empty string.

fromJson "{\"foo\": 55}"

Example of a query to print a newline per queries stored as a json array in the log line:

{job="loki/querier"} |= "finish in prometheus" | logfmt | line_format "{{ range $q := fromJson .queries }} {{ $q.query }} {{ end }}"

now

now returns the current local time.

{{ now }}

toDate

toDate parses a formatted string and returns the time value it represents.

{{ toDate "2006-01-02" "2021-11-02" }}

date

date returns a textual representation of the time value formatted according to the provided golang datetime layout.

{ date "2006-01-02" now }}

unixEpoch

unixEpoch returns the number of seconds elapsed since January 1, 1970 UTC.

{ unixEpoch now }}

Example of a query to filter Loki querier jobs which create time is 1 day before:

{job="loki/querier"} | label_format nowEpoch=`{{(unixEpoch now)}}`,createDateEpoch=`{{unixEpoch (toDate "2006-01-02" .createDate)}}` | label_format dateTimeDiff="{{sub .nowEpoch .createDateEpoch}}" | dateTimeDiff > 86400

default

default checks whether the string(src) is set, and returns default(d) if not set.

Signature: default(d string, src string) string

Examples:

{{ default "-" "" }} // output: -
{{ default "-" "foo" }} // output: foo

Example of a query to print a - if the http_request_headers_x_forwarded_for label is empty:

{job="access_log"} | json | line_format `{{.http_request_headers_x_forwarded_for | default "-"}}`

Matching IP addresses

Tue, 16 Jul 2024 15:42:20 +0000

Matching IP addresses

LogQL supports matching IP addresses.

With logs such as

3.180.71.3 - - [17/May/2015:08:05:32 +0000] "GET /downloads/product_1 HTTP/1.1" 304 0 "-" "Debian APT-HTTP/1.3 (0.8.16~exp12ubuntu10.21)"
80.91.33.133 - - [17/May/2015:08:05:14 +0000] "GET /downloads/product_1 HTTP/1.1" 304 0 "-" "Debian APT-HTTP/1.3 (0.8.16~exp12ubuntu10.16)"
46.4.66.76 - - [17/May/2015:08:05:45 +0000] "GET /downloads/product_1 HTTP/1.1" 404 318 "-" "Debian APT-HTTP/1.3 (1.0.1ubuntu2)"
93.180.71.3 - - [17/May/2015:08:05:26 +0000] "GET /downloads/product_1 HTTP/1.1" 404 324 "-" "Debian APT-HTTP/1.3 (0.8.16~exp12ubuntu10.21)"

the LogQL line filter is not sufficient. A line filter such as

{job_name="myapp"} |= "3.180.71.3"

also matches example IP addresses such as 93.180.71.3. A better choice uses a regexp: |~"^3.180.71.3". This regexp does not handle IPv6 addresses, and it does not match a range of IP addresses.

The LogQL support for matching IP addresses handles both IPv4 and IPv6 single addresses, as well as ranges within IP addresses and CIDR patterns.

Match IP addresses with the syntax: ip("<pattern>"). The <pattern> can be:

A single IP address. Examples: ip("192.0.2.0"), ip("::1")
A range within the IP address. Examples: ip("192.168.0.1-192.189.10.12"), ip("2001:db8::1-2001:db8::8")
A CIDR specification. Examples: ip("192.51.100.0/24"), ip("2001:db8::/32")

The IP matching can be used in both line filter and label filter expressions. When specifying line filter expressions, only the |= and != operations are allowed. When specifying label filter expressions, only the = and != operations are allowed.

Line filter examples

{job_name="myapp"} |= ip("192.168.4.5/16")

Return log lines that do not match with an IPv4 range:

{job_name="myapp"} != ip("192.168.4.5-192.168.4.20")

Label filter examples

{job_name="myapp"}
	| logfmt
	| remote_addr = ip("2001:db8::1-2001:db8::8")
	| level = "error"

Filters can be chained. This example matches log lines with all IPv4 subnet values 192.168.4.5/16 except IP address 192.168.4.2:

{job_name="myapp"}
	| logfmt
	| addr = ip("192.168.4.5/16")
	| addr != ip("192.168.4.2")

Query examples

Tue, 16 Jul 2024 15:42:20 +0000

Query examples

Some useful query examples here.

Log Query examples

Examples that filter on IP address

Return log lines that are not within a range of IPv4 addresses:
logql
```
{job_name="myapp"} != ip("192.168.4.5-192.168.4.20")
```
This example matches log lines with all IPv4 subnet values 192.168.4.5/16 except IP address 192.168.4.2:
logql
```
{job_name="myapp"}
	| logfmt
	| addr = ip("192.168.4.5/16")
	| addr != ip("192.168.4.2")
```

Examples that aid in security evaluation

Extract the user and IP address of failed logins from Linux /var/log/secure

{job="security"} 
    |~ "Invalid user.*"
    | regexp "(^(?P<user>\\S+ {1,2}){8})"
    | regexp "(^(?P<ip>\\S+ {1,2}){10})"
    | line_format "IP = {{.ip}}\tUSER = {{.user}}"

Get successful logins from Linux /var/log/secure

{job="security"}
    != "grafana_com"
    |= "session opened"
    != "sudo: "
    |regexp "(^(?P<user>\\S+ {1,2}){11})"
    | line_format "USER = {{.user}}"

Metrics Query examples

Return the per-second rate of all non-timeout errors within the last minutes per host for the MySQL job, and only include errors whose duration is above ten seconds.
```
sum by (host) (rate({job="mysql"}
    |= "error" != "timeout"
    | json
    | duration > 10s [1m]))
```