Go - Influxdb — ContextQMD

Use the InfluxDB Go client library to integrate InfluxDB into Go scripts and applications.

This guide presumes some familiarity with Go and InfluxDB. If just getting started, see Get started with InfluxDB.

Before you begin

Install Go 1.13 or later.

Add the client package your to your project dependencies.

# Add InfluxDB Go client package to your project go.mod
go get github.com/influxdata/influxdb-client-go/v2

Ensure that InfluxDB is running and you can connect to it. For information about what URL to use to connect to InfluxDB OSS or InfluxDB Cloud, see InfluxDB URLs.

Boilerplate for the InfluxDB Go Client Library

Use the Go library to write and query data from InfluxDB.

In your Go program, import the necessary packages and specify the entry point of your executable program.

package main

import (
    "context"
    "fmt"
    "time"

    "github.com/influxdata/influxdb-client-go/v2"
)

Define variables for your InfluxDB bucket, organization, and token.

bucket := "example-bucket"
org := "example-org"
token := "example-token"
// Store the URL of your InfluxDB instance
url := "http://localhost:8086"

Create the the InfluxDB Go client and pass in the url and token parameters.
go
```
client := influxdb2.NewClient(url, token)
```
Create a write client with the WriteAPIBlocking method and pass in the org and bucket parameters.
go
```
writeAPI := client.WriteAPIBlocking(org, bucket)
```
To query data, create an InfluxDB query client and pass in your InfluxDB org.
go
```
queryAPI := client.QueryAPI(org)
```

Write data to InfluxDB with Go

Use the Go library to write data to InfluxDB.

Create a point and write it to InfluxDB using the WritePoint method of the API writer struct.

Close the client to flush all pending writes and finish.

p := influxdb2.NewPoint("stat",
  map[string]string{"unit": "temperature"},
  map[string]interface{}{"avg": 24.5, "max": 45},
  time.Now())
writeAPI.WritePoint(context.Background(), p)
client.Close()

Complete example write script

func main() {
    bucket := "example-bucket"
    org := "example-org"
    token := "example-token"
    // Store the URL of your InfluxDB instance
    url := "http://localhost:8086"
    // Create new client with default option for server url authenticate by token
    client := influxdb2.NewClient(url, token)
    // User blocking write client for writes to desired bucket
    writeAPI := client.WriteAPIBlocking(org, bucket)
    // Create point using full params constructor
    p := influxdb2.NewPoint("stat",
        map[string]string{"unit": "temperature"},
        map[string]interface{}{"avg": 24.5, "max": 45},
        time.Now())
    // Write point immediately
    writeAPI.WritePoint(context.Background(), p)
    // Ensures background processes finishes
    client.Close()
}

Query data from InfluxDB with Go

Use the Go library to query data stored in InfluxDB.

Create a Flux query and pass the bucket parameter with your bucket name.
js
```
from(bucket:"<bucket>")
    |> range(start: -1h)
    |> filter(fn: (r) => r._measurement == "stat")
```
The query client sends the Flux query to InfluxDB and returns the results as a FluxRecord object with a table structure.

The query client includes the following methods:

Query: Sends the Flux query to InfluxDB.
Next: Iterates over the query response.
TableChanged: Identifies when the group key changes.
Record: Returns the last parsed FluxRecord and gives access to value and row properties.
Value: Returns the actual field value.

result, err := queryAPI.Query(context.Background(), `from(bucket:"<bucket>")
    |> range(start: -1h) 
    |> filter(fn: (r) => r._measurement == "stat")`)
if err == nil {
    for result.Next() {
        if result.TableChanged() {
            fmt.Printf("table: %s\n", result.TableMetadata().String())
        }
        fmt.Printf("value: %v\n", result.Record().Value())
    }
    if result.Err() != nil {
        fmt.Printf("query parsing error: %s\n", result.Err().Error())
    }
} else {
    panic(err)
}

The FluxRecord object includes the following methods for accessing your data:

Table(): Returns the index of the table the record belongs to.
Start(): Returns the inclusive lower time bound of all records in the current table.
Stop(): Returns the exclusive upper time bound of all records in the current table.
Time(): Returns the time of the record.
Value() : Returns the actual field value.
Field(): Returns the field name.
Measurement(): Returns the measurement name of the record.
Values(): Returns a map of column values.
ValueByKey(<your_tags>): Returns a value from the record for given column key.

Complete example query script

 func main() {
    // Create client
    client := influxdb2.NewClient(url, token)
    // Get query client
    queryAPI := client.QueryAPI(org)
    // Get QueryTableResult
    result, err := queryAPI.Query(context.Background(), `from(bucket:"my-bucket")|> range(start: -1h) |> filter(fn: (r) => r._measurement == "stat")`)
    if err == nil {
        // Iterate over query response
        for result.Next() {
            // Notice when group key has changed
            if result.TableChanged() {
                fmt.Printf("table: %s\n", result.TableMetadata().String())
            }
            // Access data
            fmt.Printf("value: %v\n", result.Record().Value())
        }
        // Check for an error
        if result.Err() != nil {
            fmt.Printf("query parsing error: %s\n", result.Err().Error())
        }
    } else {
        panic(err)
    }
    // Ensures background processes finishes
    client.Close()
}

For more information, see the Go client README on GitHub.