influxdb-client-kotlin

The reference Kotlin client that allows query and write for the InfluxDB 2.x by Kotlin Channel coroutines.

Documentation

This section contains links to the client library documentation.

• Product documentation, Getting Started
• Examples
• API Reference
• Changelog

Features

• Querying data using Flux language
• Writing data
• Advanced Usage

Queries

The QueryKotlinApi supports asynchronous queries by Kotlin Channel coroutines.

The following example demonstrates querying using the Flux language:

package example

import com.influxdb.client.kotlin.InfluxDBClientKotlinFactory
import kotlinx.coroutines.channels.consumeEach
import kotlinx.coroutines.channels.filter
import kotlinx.coroutines.channels.take
import kotlinx.coroutines.runBlocking

fun main(args: Array<String>) = runBlocking {

    val influxDBClient = InfluxDBClientKotlinFactory
            .create("http://localhost:8086", "my-token".toCharArray(), "my-org")

    val fluxQuery = ("from(bucket: \"my-bucket\")\n"
            + " |> range(start: -1d)"
            + " |> filter(fn: (r) => (r[\"_measurement\"] == \"cpu\" and r[\"_field\"] == \"usage_system\"))")

    //Result is returned as a stream
    val results = influxDBClient.getQueryKotlinApi().query(fluxQuery)

    //Example of additional result stream processing on client side
    results
            //filter on client side using `filter` built-in operator
            .filter { "cpu0" == it.getValueByKey("cpu") }
            //take first 20 records
            .take(20)
            //print results
            .consumeEach { println("Measurement: ${it.measurement}, value: ${it.value}") }

    influxDBClient.close()
}

It is possible to parse a result line-by-line using the queryRaw method:

package example

import com.influxdb.client.kotlin.InfluxDBClientKotlinFactory
import kotlinx.coroutines.channels.consumeEach
import kotlinx.coroutines.runBlocking

fun main(args: Array<String>) = runBlocking {

    val influxDBClient = InfluxDBClientKotlinFactory
            .create("http://localhost:8086", "my-token".toCharArray(), "my-org")

    val fluxQuery = ("from(bucket: \"my-bucket\")\n"
            + " |> range(start: -5m)"
            + " |> filter(fn: (r) => (r[\"_measurement\"] == \"cpu\" and r[\"_field\"] == \"usage_system\"))"
            + " |> sample(n: 5, pos: 1)")

    //Result is returned as a stream
    val results = influxDBClient.getQueryKotlinApi().queryRaw(fluxQuery)

    //print results
    results.consumeEach { println("Line: $it") }

    influxDBClient.close()
}

Writes

The WriteKotlinApi supports ingest data by:

• DataPoint
• LineProtocol
• Data class
• List of above items

The following example shows how to use various type of data:

package example

import com.influxdb.annotations.Column
import com.influxdb.annotations.Measurement
import com.influxdb.client.domain.WritePrecision
import com.influxdb.client.kotlin.InfluxDBClientKotlinFactory
import com.influxdb.client.write.Point
import kotlinx.coroutines.flow.collect
import kotlinx.coroutines.flow.consumeAsFlow
import kotlinx.coroutines.runBlocking
import java.time.Instant

fun main() = runBlocking {

    val org = "my-org"
    val bucket = "my-bucket"

    //
    // Initialize client
    //
    val client = InfluxDBClientKotlinFactory
        .create("http://localhost:8086", "my-token".toCharArray(), org, bucket)

    val writeApi = client.getWriteKotlinApi()

    //
    // Write by Data Point
    //
    val point = Point.measurement("temperature")
        .addTag("location", "west")
        .addField("value", 55.0)
        .time(Instant.now().toEpochMilli(), WritePrecision.MS)

    writeApi.writePoint(point)

    //
    // Write by LineProtocol
    //
    writeApi.writeRecord("temperature,location=north value=60.0", WritePrecision.NS)

    //
    // Write by DataClass
    //
    val temperature = Temperature("south", 62.0, Instant.now())

    writeApi.writeMeasurement(temperature, WritePrecision.NS)

    //
    // Query results
    //
    val fluxQuery =
        """from(bucket: "$bucket") |> range(start: 0) |> filter(fn: (r) => (r["_measurement"] == "temperature"))"""

    client
        .getQueryKotlinApi()
        .query(fluxQuery)
        .consumeAsFlow()
        .collect { println("Measurement: ${it.measurement}, value: ${it.value}") }

    client.close()
}

@Measurement(name = "temperature")
data class Temperature(
    @Column(tag = true) val location: String,
    @Column val value: Double,
    @Column(timestamp = true) val time: Instant
)

• sources - KotlinWriteApi.kt

Advanced Usage

Client configuration file

A client can be configured via configuration file. The configuration file has to be named as influx2.properties and has to be in root of classpath.

The following options are supported:

Property name	default	description
influx2.url	-	the url to connect to InfluxDB
influx2.org	-	default destination organization for writes and queries
influx2.bucket	-	default destination bucket for writes
influx2.token	-	the token to use for the authorization
influx2.logLevel	NONE	rest client verbosity level
influx2.readTimeout	10000 ms	read timeout
influx2.writeTimeout	10000 ms	write timeout
influx2.connectTimeout	10000 ms	socket timeout
influx2.precision	NS	default precision for unix timestamps in the line protocol
influx2.clientType	-	to customize the User-Agent HTTP header

The influx2.readTimeout, influx2.writeTimeout and influx2.connectTimeout supports ms, s and m as unit. Default is milliseconds.

Configuration example

influx2.url=http://localhost:8086
influx2.org=my-org
influx2.bucket=my-bucket
influx2.token=my-token
influx2.logLevel=BODY
influx2.readTimeout=5s
influx2.writeTimeout=10s
influx2.connectTimeout=5s

and then:

val influxDBClient = InfluxDBClientKotlinFactory.create();

Client connection string

A client can be constructed using a connection string that can contain the InfluxDBClientOptions parameters encoded into the URL.

val influxDBClient = InfluxDBClientKotlinFactory
            .create("http://localhost:8086?readTimeout=5000&connectTimeout=5000&logLevel=BASIC", token)

The following options are supported:

Property name	default	description
org	-	default destination organization for writes and queries
bucket	-	default destination bucket for writes
token	-	the token to use for the authorization
logLevel	NONE	rest client verbosity level
readTimeout	10000 ms	read timeout
writeTimeout	10000 ms	write timeout
connectTimeout	10000 ms	socket timeout
precision	NS	default precision for unix timestamps in the line protocol
clientType	-	to customize the User-Agent HTTP header

The readTimeout, writeTimeout and connectTimeout supports ms, s and m as unit. Default is milliseconds.

Gzip support

InfluxDBClientKotlin does not enable gzip compress for http requests by default. If you want to enable gzip to reduce transfer data's size, you can call:

influxDBClient.enableGzip();

Log HTTP Request and Response

The Requests and Responses can be logged by changing the LogLevel. LogLevel values are NONE, BASIC, HEADER, BODY. Note that applying the BODY LogLevel will disable chunking while streaming and will load the whole response into memory.

influxDBClient.setLogLevel(LogLevel.HEADERS)

Check the server status

Server availability can be checked using the influxDBClient.ping() endpoint.

Construct queries using the flux-dsl query builder

package example

import com.influxdb.client.kotlin.InfluxDBClientKotlinFactory
import com.influxdb.query.dsl.Flux
import com.influxdb.query.dsl.functions.restriction.Restrictions
import kotlinx.coroutines.channels.consumeEach
import kotlinx.coroutines.channels.filter
import kotlinx.coroutines.channels.take
import kotlinx.coroutines.runBlocking
import java.time.temporal.ChronoUnit

fun main(args: Array<String>) = runBlocking {

    val influxDBClient = InfluxDBClientKotlinFactory
            .create("http://localhost:8086", "my-token".toCharArray(), "my-org")

    val mem = Flux.from("my-bucket")
            .range(-30L, ChronoUnit.MINUTES)
            .filter(Restrictions.and(Restrictions.measurement().equal("mem"), Restrictions.field().equal("used_percent")))

    //Result is returned as a stream
    val results = influxDBClient.getQueryKotlinApi().query(mem.toString())

    //Example of additional result stream processing on client side
    results
            //filter on client side using `filter` built-in operator
            .filter { (it.value as Double) > 55 }
            // take first 20 records
            .take(20)
            //print results
            .consumeEach { println("Measurement: ${it.measurement}, value: ${it.value}") }

    influxDBClient.close()
}

Version

The latest version for Maven dependency:

<dependency>
  <groupId>com.influxdb</groupId>
  <artifactId>influxdb-client-kotlin</artifactId>
  <version>7.2.0</version>
</dependency>

Or when using with Gradle:

dependencies {
    implementation "com.influxdb:influxdb-client-kotlin:7.2.0"
}

Snapshot Repository

The snapshots are deployed into OSS Snapshot repository.

Maven

<repository>
    <id>ossrh</id>
    <name>OSS Snapshot repository</name>
    <url>https://oss.sonatype.org/content/repositories/snapshots/</url>
    <releases>
        <enabled>false</enabled>
    </releases>
    <snapshots>
        <enabled>true</enabled>
    </snapshots>
</repository>

Gradle

repositories {
    maven { url "https://oss.sonatype.org/content/repositories/snapshots" }
}