JarCastingPrmoetheus metrics parser
Prometheus metrics parser is small, dependency-free Scala library for parsing Prometheus metrics base on exposition formats.
Getting started
Parse metrics
You can start using library by adding following dependency to build.sbt:
libraryDependencies += "com.github.pawelj-pl" %% "prometheus_metrics_parser" % "<libraryVersion>"
Now you can create parser Instance:
import com.github.pawelj_pl.prometheus_metrics_parser.parser.Parser
val parser = Parser()
and parse provided metrics with one of available methods:
val input: String =
"""
|# HELP some_metric First metric
|# TYPE some_metric counter
|some_metric{foo = "bar"} 123 999
""".stripMargin
val eitherResult: Either[ParseError, List[Metric]] = parser.parseE(input) // Right(List(Counter(some_metric,Some(First metric),List(MetricValue(Map(foo -> bar),123.0,Some(999),None)))))
val optionResult: Option[List[Metric]] = parser.parseOpt(input) // Some(List(Counter(some_metric,Some(First metric),List(MetricValue(Map(foo -> bar),123.0,Some(999),None)))))
val result: List[Metric] = parser.unsafeParse(input) //List(Counter(some_metric,Some(First metric),List(MetricValue(Map(foo -> bar),123.0,Some(999),None))))
The last one is marked as unsafe, because it throws exception (com.github.pawelj_pl.prometheus_metrics_parser.parser.ParseException) on error.
Rendering metrics
Each instance of com.github.pawelj_pl.prometheus_metrics_parser.Metric can be rendered to string representing set of Prometheus metric lines. For example:
import com.github.pawelj_pl.prometheus_metrics_parser.Metric
import com.github.pawelj_pl.prometheus_metrics_parser.Metric.Counter
import com.github.pawelj_pl.prometheus_metrics_parser.MetricValue
val input: Metric = Counter(
"some_metric",
Some("Help content"),
List(
MetricValue(Map("foo" -> "bar"), 123D, Some(111L), None),
MetricValue(Map("foo" -> "baz"), Double.NaN, Some(999L), None)
)
)
val result: String = input.render
result will contain following string:
# HELP some_metric Help content
# TYPE some_metric counter
some_metric{foo="bar"} 123 111
some_metric{foo="baz"} Nan 999
It can be useful for transforming existing metrics. Some examples:
Filtering metrics
import com.github.pawelj_pl.prometheus_metrics_parser.Metric
import com.github.pawelj_pl.prometheus_metrics_parser.Metric.Counter
import com.github.pawelj_pl.prometheus_metrics_parser.MetricValue
import com.github.pawelj_pl.prometheus_metrics_parser.parser.Parser
val input =
"""# TYPE metric1 counter
|metric1{foo="bar"} 123
|metric1{foo="baz"} 222
|# TYPE metric2 counter
|metric2 333
|# TYPE other_metric counter
|other_metric 999
""".stripMargin
val parser = Parser()
val parsed = parser.parseE(input)
val updated = parsed
.map(_
.filter(_.name.startsWith("metric"))
.map(_.render)
.mkString("\n\n"))
val result = updated.getOrElse("")
result will contain following string:
# TYPE metric1 counter
metric1{foo="bar"} 123
metric1{foo="baz"} 222
# TYPE metric2 counter
metric2 333
Updating labels
import com.github.pawelj_pl.prometheus_metrics_parser.Metric.{Counter, Gauge, Histogram, Summary, Untyped}
import com.github.pawelj_pl.prometheus_metrics_parser.parser.Parser
val input =
"""# TYPE metric1 counter
|metric1 123
|metric1{foo="bar"} 222
""".stripMargin
val parser = new Parser()
val parsed = parser.parseE(input).getOrElse(List.empty)
val updated = parsed.map {
case Counter(name, help, values) => Counter(name, help, values.map(v => v.copy(labels = v.labels + ("x" -> "y"))))
case Gauge(name, help, values) => Gauge(name, help, values.map(v => v.copy(labels = v.labels + ("x" -> "y"))))
case Untyped(name, help, values) => Untyped(name, help, values.map(v => v.copy(labels = v.labels + ("x" -> "y"))))
case Summary(name, help, values, sums, counts) => Summary(name, help, values.map(v => v.copy(labels = v.labels + ("x" -> "y"))), sums, counts)
case Histogram(name, help, values, sums, counts) => Histogram(name, help, values.map(v => v.copy(labels = v.labels + ("x" -> "y"))), sums, counts)
}
val result = updated.map(_.render).mkString("\n\n")
result should contain following string:
# TYPE metric1 counter
metric1{x="y"} 123
metric1{foo="bar", x="y"} 222