grafana loki query example grafana loki query example

I've looked through documentation, and so far, I haven't found any such Loki query. The Derived Fields configuration helps you: For example, you can link to your tracing backend directly from your logs, or link to a user profile page if the log line contains a corresponding userId. Note: By signing up, you agree to be emailed related product-level information. For more information about LogQL, see LogQL. You can specify one or more expressions in this way, the same error level logs will be written to stderr and the actual log messages are generated in JSON format and a new log message will be created every 500 milliseconds. Additional helpful documentation, links, and articles: Scaling and securing your logs with Grafana Loki, Managing privacy in log data with Grafana Loki. Well demo all the highlights of the major release: new and updated visualizations and themes, data source improvements, and Enterprise features. Step 1: Go to Grafana Configurations and Click on "Data Sources". Signature: func(a interface{}, v interface{}) int64, Signature: func(i interface{}) float64. You can use double quoted string for the template or backticks `{{.label_name}}` to avoid the need to escape special characters. New navigation. By default, the matching is case-sensitive and can be switched to be case-insensitive by prefixing the regular expression with (?i). Go to that address and login with the username "admin" and password "admin". For example, | json first_server="servers[0]", ua="request.headers[\"User-Agent\"] will extract from the following document: If an array or an object returned by an expression, it will be assigned to the label in json format. The above query will result in a log line of 1.1.1.1 200 3. Vector elements for which the expression is not true or which do not find a match on the other side of the expression get dropped from the result, while the others are propagated into a result vector. This powerful feature creates metrics from logs. Here we deploy a sample application that is a fake logger with debug, info and warning logs output to stdout. Sets the name you use to refer to the data source in panels and queries. Log queries A log query consists of two parts: log stream selector, and a search expression. If the bool modifier is provided, vector elements that would be dropped instead have the value 0 and vector elements that would be kept have the value 1. Connect and share knowledge within a single location that is structured and easy to search. (e.g .label_name). By default, the pattern expression is anchored at the beginning of the log line, and you can use <_> at the beginning of the expression to anchor the expression at the beginning. There are two types of LogQL queries: Log queries return the contents of log lines. Sets the data source thats pre-selected for new panels. Note: By signing up, you agree to be emailed related product-level information. For instructions on how to add a data source to Grafana, refer to the administration documentation. Grafana Labs uses cookies for the normal operation of this website. The opposite is false. We dont need most of the preceding log data, we just need to use <_> for placeholders, which is obviously much simpler than regular expressions. Step 3: Search by the name Loki. and can be equivalently expressed by a comma, a space or another pipe. The syntax: The label list provided with the group modifier contains additional labels from the one-side that are included in the result metrics. Once youve added the Loki data source, you can configure it so that your Grafana instances users can create queries in its query editor when they build dashboards, use Explore, and annotate visualizations. Other elements are dropped. LogQL supports a variety of value types that are automatically inferred from the query input. The following label matching operators are supported: Note: Unlike the line filter regex expressions, the =~ and !~ regex operators are fully anchored. I have been running Grafana Loki on my hobby machine which only has 2 core and 2 GB memory without any hiccup for over 2 years now. =: exact match ! Signature: nindent(spaces int,src string) string. This contrived query will return the intersection of these queries, effectively rate({app="bar"}): Comparison operators are defined between scalar/scalar, vector/scalar, and vector/vector value pairs. The filter operators can be chained and will filter expressions in order, and the resulting log lines must satisfy each filter. Returns the number of seconds elapsed since January 1, 1970 UTC. . the query results. The replacement string is substituted directly, without using Expand. Note: By signing up, you agree to be emailed related product-level information. Signature: minf(a interface{}, i interface{}) float64, Returns the greatest float value greater than or equal to input value, Returns the greatest float value less than or equal to input value. $2 with the second etc. For example, logfmt | duration > 1m and bytes_consumed > 20MB filters the expression. After writing in the log stream selector, the resulting log data set can be further filtered using a search expression, which can be text or a regular expression, e.g. They cannot start with a digit.). Using Duration, Number and Bytes will convert the label value prior to comparision and support the following comparators: For instance, logfmt | duration > 1m and bytes_consumed > 20MB. Return the streams matching app=foo without app labels that have higher counts within the last minute than their counterparts matching app=bar without app labels: Same as above, but vectors have their values set to 1 if they pass the comparison or 0 if they fail/would otherwise have been filtered out: When chaining or combining operators, you have to consider operator precedence: This should be clearly stated in examples and documentation: In Grafana 7, you have the transformations tab, select "Labels to Fields . LogQL uses labels and operators for filtering. A log pipeline is a set of stage expressions that are chained together and applied to the selected log streams. Use this function to convert to lower case. defines the field name example. Grafana lists these variables in dropdown select boxes at the top of the dashboard to help you change the data displayed in your dashboard. # A trusted profile will be used for authenticating with COS. We can either pass # the trusted profile name or trusted profile ID along with the compute resource token file. This is useful when aligning multi-line strings. Defines a regular expression to evaluate on the log message and capture part of it as the value of the new field. Parser expression can parse and extract labels from the log content. When both side are label identifiers, for example dst=src, the operation will rename the src label into dst. Signature: unixEpoch(date time.Time) string. but only the specified pairs within the stream selector are used to determine Label formatting is used to sanitize the query while the line format reduce the amount of information and creates a tabular output. You can combine the unpack and json parsers (or any other parsers) if the original embedded log line is of a specific format. of these in any level of nesting (my.list[0]["field"]). Unexpected uint64 behaviour 0xFFFF'FFFF'FFFF'FFFF - 1 = 0? You can use and and or to concatenate multiple predicates that represent and and or binary operations, respectively. It takes a single string parameter | line_format "{{.label_name}}", which is the template format. In this example, log streams that have 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. After the modification, you can normally see the relevant event information in the cluster in Dashboard, but it is recommended to replace the query statement in the panel with a record rule. This log line can be parsed with the expression, - - <_> " <_>" <_> "" <_>. include only those log lines that contain the string metrics.go Grafana, often with Prometheus, is a popular open source platform for monitoring and observability that can be used to query, visualize, and create alerts on a number of metric and data sources. Note: By signing up, you agree to be emailed related product-level information. Signature: unixEpochMillis(date time.Time) string. In a chained pipeline, the result of each command is passed as the last argument of the following command. The syntax: This example will return every machine total count within the last minutes ratio in app foo: Many-to-one and one-to-many matchings occur when each vector element on the one-side can match with multiple elements on the many-side. For example, lets look at the following log line data. Only when using the bottomk and topk functions, we can enter the relevant arguments to the functions. =~: regex matches. rev2023.4.21.43403. Connect Grafana to data sources, apps, and more, with Grafana Alerting, Grafana Incident, and Grafana OnCall, Frontend application observability web SDK, Try out and share prebuilt visualizations, Contribute to technical documentation provided by Grafana Labs, Help build the future of open source observability software 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. These can significantly consume Lokis query performance. line_format also supports math functions. within the last minutes per host for the MySQL job, For internal links, you can select the target data source from a selector. The regular expression must contain at least one named submatch (e.g. What woodwind & brass instruments are most air efficient? This means that the . Returns the number of nanoseconds elapsed since January 1, 1970 UTC. Install Grafana Loki with Docker or Docker Compose, 0003: Query fairness across users within tenants, Many-to-one and one-to-many vector matches, A numeric label filter may fail to turn a label value into a number. A special property _entry will also be used to replace the original log line. A query in Grafana, based on a Loki data source. A complete query with a regular expression: Filter operators can be chained. See vector aggregation examples for query examples that use vector aggregation expressions. Obviously the mathematical operations in LogQL are oriented towards interval vector operations, and the supported binary operators in LogQL are as follows. Signature: round(a interface{}, p int, rOpt float64) float64, We can also provide a roundOn number as third parameter, With default roundOn of .5 the above value would be 123.88571, Signature: toFloat64(v interface{}) float64. VASPKIT and SeeK-path recommend different paths. Line filter expressions support stripping ANSI sequences (color codes) from LogQL: Log query language LogQL is Grafana Loki's PromQL-inspired query language. Loki supports functions to operate on data. To avoid these problems, dont add labels until you know you need them. For example, select pod and then select the loki-grafana pod to query all logs from this specific pod. To make querying efficient, If you cant, the pattern and regexp parsers can be used for log lines with an unusual structure. Install Grafana Loki with Docker or Docker Compose, 0003: Query fairness across users within tenants, regexReplaceAll and regexReplaceAllLiteral. over the aggregated logs from the matching log streams. The following query shows how you can reformat a log line to make it easier to read on screen. Grafana Loki was introduced in 2018 as a lightweight and cost-effective log aggregation system inspired by Prometheus. Each expression can filter out, parse, or mutate log lines and their respective labels. Administrators can also configure the data source via YAML with Grafanas provisioning system. A predicate contains a label identifier, an operation and a value to compare the label with. Mulitply numbers. The label filter after the log stream selector or at end of the log pipeline. ', referring to the nuclear power plant in Ignalina, mean? Unwrapped ranges uses extracted labels as sample values instead of log lines. 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. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. After parsing, these attributes can be extracted as follows. Placing them at the beginning improves the performance of the query, For grouping tags, we can use without or by to distinguish them. This is mainly to allow filtering errors from the metric extraction. I am interested in monitoring a variable in a log that takes different values over time. By default, the system matches and, unless, and or operations with all entries in the right vector. For example, the following log passing through the pipeline | json will produce the following Map data. Line filter expressions are the fastest way to filter logs once the While every query will have a stream selector, For example, while the results are the same, the following query {job="mysql"} |= "error" |json | line_format "{{.err}}" will be faster than {job="mysql"} | json | line_format "{{.message}}" |= "error", Log line filter expressions are the fastest way to filter logs after log stream selectors . For example cluster="namespace" where cluster is the tag identifier, the operator is = and the value is "namespace". Implement a health check with a simple query: Double the rate of a a log streams entries: Get proportion of warning logs to error logs for the foo app. Sorry, an error occurred. Install Grafana Loki with Docker or Docker Compose, 0003: Query fairness across users within tenants. There are examples in Multiple parsers. Use this function to repeat a string multiple times. For example /path/subpath and /path/othersubpath are grouped under /path. To extract the method and the path of this logfmt log line. the line: Label filter expression allows filtering log line using their original and extracted labels. The following example shows the operation of a complete log query. Between two scalars, these operators result in another scalar that is either 0 (false) or 1 (true), depending on the comparison result. Note: By signing up, you agree to be emailed related product-level information. If start is < 0, this calls value[:end]. Only field access (my.field, my["field"]) and array access (list[0]) are currently supported, as well as combinations of these in any level of nesting (my.list[0]["field"]). 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: 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: parameter is required when using topk and bottomk. Connect Grafana to data sources, apps, and more, with Grafana Alerting, Grafana Incident, and Grafana OnCall, Frontend application observability web SDK, Try out and share prebuilt visualizations, Contribute to technical documentation provided by Grafana Labs, Help build the future of open source observability software The | label_format expression can rename, modify or add labels. To configure basic settings for the data source, complete the following steps: Under Your connections, click Data sources. The matching is case-sensitive by default. There are two line filters: I used a Grafana transformation which seems to work Add field from calculation Binary operation Select the query and do + 0 I then hide the original query It would be easier if we could do this in the original query though 1 Like waterdrop01 September 28, 2021, 3:39pm #9 Agreed! This means that the regex expression must match against the entire string, including newlines. The log stream selector determines which log streams should be included in your query results. Downloads. Use <_> at the beginning of the expression if you dont want to anchor the expression at the start. Grafana provides built-in support for Loki. The above example means that all log streams with the tag app and the value mysql and the tag name and the value mysql-backup will be included in the query results. Sets the HTTP protocol, IP, and port of your Loki instance, such as. vector1 unless vector2 results in a vector consisting of the elements of vector1 for which there are no elements in vector2 with exactly matching label sets. If the conversion of the tag value fails, the log line is not filtered and a __error__ tag is added. LogQL also supports a limited number of interval vector metric statements, similar to PromQL, with the following 4 functions. See Unwrap examples for query examples that use the unwrap expression. Which one to choose? Between two vectors, a binary arithmetic operator is applied to each entry in the left-hand side vector and its matching element in the right-hand vector. The = operator after the label name is a label matching operator. regexReplaceAll returns a copy of the input string, replacing matches of the Regexp with the replacement string replacement. Signature: indent(spaces int,src string) string. Install Grafana Loki with Docker or Docker Compose, 0003: Query fairness across users within tenants. I don't know how to write this query. A log pipeline can be attached to a log stream selector to further process and filter log streams. 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. The log stream selector is specified by one or more comma-separated key-value pairs. To avoid escaping the featured character, you can use single quotes instead of double quotes when quoting a string, for example \w+1 is the same as \w+. This function returns the current log lines timestamp. Signature: default(d string, src string) string. Example of a query to print how many times XYZ occurs in a line: Convert a humanized byte string to bytes using go-humanize, Convert a humanized time duration to seconds using time.ParseDuration, Signature: duration_seconds(string) float64. Return the largest of a series of integers: Signature: max(a interface{}, i interface{}) int64. Use this function to convert to upper case. Calculate the number of times the kernel has experienced oom in the last 5 minutes. All log streams that have both a label of app whose value is mysql What did you expect to happen? Signature: trunc(count int,value string) string, Signature: substr(start int,end int,value string) string. Using basic authorization and a derived field: You must escape the dollar ($) character in YAML values because it can be used to interpolate environment variables: In this example, the Jaeger data sources uid value should match the Loki data sources datasourceUid value. Use this function to trim just the suffix from a string. LogQL shares the range vector concept of Prometheus. For example, |json first_server="servers[0]", ua="request.headers[\"User-Agent\"] will extract tags from the following log files. A Log Stream represents log entries that have the same metadata (set of Labels). Grafana Loki, a log processing tool, is designed to work at high speeds and large scale, on the minimum possible resources. Supports multiple numbers. The trim function removes space from either side of a string. This indents each line contained in the .query by four (4) spaces. Usually we do a comparison of thresholds after using interval vector calculations, which is useful for alerting, e.g. 1-Local-Configuration-Example.yaml auth_enabled: false server: http_listen_port: 3100 common: ring: instance_addr: 127.0.0.1 kvstore: store: inmemory replication_factor: 1 path_prefix: /tmp/loki schema_config: configs: - from: 2020-05-15 store: boltdb-shipper object_store: filesystem schema: v11 index: prefix: index_ period: 24h For multi-row LogQL queries, you can use # to exclude whole or partial rows. To extract the method and the path, Click on Select. For example, given these fake logs: GET /foo/bar GET /foo/baz GET /quux/ GET /foo GET /baz Use {host=~ ".+"} That should work always. In addition, we can format the output logs according to our needs using line_format, for example, we use the query statement {app="fake-logger"} | json |is_even="true" | line_format "logs generated in {{.time}} on {{.level}}@ {{.pod}} Pod generated log {{.msg}}" to format the log output. The log stream selector is optionally followed by a log pipeline for further processing and filtering of log stream information, which consists of a set of expressions, each of which performs relevant filtering for each log line in left-to-right order, each of which can filter, parse and change the log line content and its respective label. The pattern parser is easier and faster to write; it also outperforms the regexp parser. A metric conversion for a label may fail. The = operator after the tag name is a tag matching operator, and there are several tag matching operators supported in LogQL. Its possible to strip ANSI sequences from the log line, making it easier For example, using the | unpack parser, you can get tags as follows. Downloads. If a log line is filtered out by an expression, the pipeline will stop there and start processing the next line. We should use predefined parsers like json and logfmt whenever possible, it will be easier, and when the log line structure is unusual, you can use regexp, which allows you to use multiple parsers in the same log pipeline, which is useful when you are parsing complex logs. Content Discovery initiative April 13 update: Related questions using a Review our technical responses for the 2023 Developer Survey, Start and end parameters in query label_values (filename) loki, Collecting logs with fluentbit to loki - Indexing custom labels. Inspired by PromQL, Loki also has its own query language, called LogQL, which is like a distributed grep that aggregates views of logs. They can be referenced using they label name prefixed by a . Signature: replace(old string, new string, src string) string. and do not include the string timeout. All of the following expressions are equivalent: By default, multiple predicates are prioritized from right to left. Install Grafana Loki with Docker or Docker Compose, 0003: Query fairness across users within tenants. It will first evaluate duration>=20ms or method="GET" , to first evaluate method="GET" and size<=20KB , make sure to use the appropriate brackets as shown below. An example that mutates is the expression.