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Use the influxctl CLI to write line protocol data

Use the influxctl CLI to write line protocol data to InfluxDB Clustered.

Construct line protocol

With a basic understanding of line protocol, you can construct data in line protocol format and write it to InfluxDB. Consider a use case where you collect data from sensors in your home. Each sensor collects temperature, humidity, and carbon monoxide readings. To collect this data, use the following schema:

  • measurement: home
    • tags
      • room: Living Room or Kitchen
    • fields
      • temp: temperature in °C (float)
      • hum: percent humidity (float)
      • co: carbon monoxide in parts per million (integer)
    • timestamp: Unix timestamp in second precision

The following line protocol represents the schema described above:

home,room=Living\ Room temp=21.1,hum=35.9,co=0i 1641024000
home,room=Kitchen temp=21.0,hum=35.9,co=0i 1641024000
home,room=Living\ Room temp=21.4,hum=35.9,co=0i 1641027600
home,room=Kitchen temp=23.0,hum=36.2,co=0i 1641027600
home,room=Living\ Room temp=21.8,hum=36.0,co=0i 1641031200
home,room=Kitchen temp=22.7,hum=36.1,co=0i 1641031200
home,room=Living\ Room temp=22.2,hum=36.0,co=0i 1641034800
home,room=Kitchen temp=22.4,hum=36.0,co=0i 1641034800
home,room=Living\ Room temp=22.2,hum=35.9,co=0i 1641038400
home,room=Kitchen temp=22.5,hum=36.0,co=0i 1641038400
home,room=Living\ Room temp=22.4,hum=36.0,co=0i 1641042000
home,room=Kitchen temp=22.8,hum=36.5,co=1i 1641042000

For this tutorial, you can either pass this line protocol directly to the influxctl write command as a string, via stdin, or you can save it to and read it from a file.

Write the line protocol to InfluxDB

Use the influxctl write command to write the home sensor sample data to your InfluxDB cluster. Provide the following:

  • The database name using the --database flag

  • A database token (with write permissions on the target database) using the --token flag

  • The timestamp precision as seconds (s) using the --precision flag

  • Line protocol. Pass the line protocol in one of the following ways:

    • a string on the command line
    • a path to a file that contains the query
    • a single dash (-) to read the query from stdin
influxctl write \
  --database 
DATABASE_NAME
\
--token
DATABASE_TOKEN
\
--precision s \ 'home,room=Living\ Room temp=21.1,hum=35.9,co=0i 1641024000 home,room=Kitchen temp=21.0,hum=35.9,co=0i 1641024000 home,room=Living\ Room temp=21.4,hum=35.9,co=0i 1641027600 home,room=Kitchen temp=23.0,hum=36.2,co=0i 1641027600 home,room=Living\ Room temp=21.8,hum=36.0,co=0i 1641031200 home,room=Kitchen temp=22.7,hum=36.1,co=0i 1641031200 home,room=Living\ Room temp=22.2,hum=36.0,co=0i 1641034800 home,room=Kitchen temp=22.4,hum=36.0,co=0i 1641034800 home,room=Living\ Room temp=22.2,hum=35.9,co=0i 1641038400 home,room=Kitchen temp=22.5,hum=36.0,co=0i 1641038400 home,room=Living\ Room temp=22.4,hum=36.0,co=0i 1641042000 home,room=Kitchen temp=22.8,hum=36.5,co=1i 1641042000'

Replace the following:

  • DATABASE_NAME: Name of the database to write to.
  • DATABASE_TOKEN: Database token with write permissions on the target database.
  1. In your terminal, enter the following command to create the sample data file:

    cat <<EOF > ./home.lp && 
    LINE_PROTOCOL_FILEPATH
    =./home.lp
    home,room=Living\ Room temp=21.1,hum=35.9,co=0i 1641024000 home,room=Kitchen temp=21.0,hum=35.9,co=0i 1641024000 home,room=Living\ Room temp=21.4,hum=35.9,co=0i 1641027600 home,room=Kitchen temp=23.0,hum=36.2,co=0i 1641027600 home,room=Living\ Room temp=21.8,hum=36.0,co=0i 1641031200 home,room=Kitchen temp=22.7,hum=36.1,co=0i 1641031200 home,room=Living\ Room temp=22.2,hum=36.0,co=0i 1641034800 home,room=Kitchen temp=22.4,hum=36.0,co=0i 1641034800 home,room=Living\ Room temp=22.2,hum=35.9,co=0i 1641038400 home,room=Kitchen temp=22.5,hum=36.0,co=0i 1641038400 home,room=Living\ Room temp=22.4,hum=36.0,co=0i 1641042000 home,room=Kitchen temp=22.8,hum=36.5,co=1i 1641042000 EOF
  1. Enter the following CLI command to write the data from the sample file:

    influxctl write \
      --database 
    DATABASE_NAME
    \
    --token
    DATABASE_TOKEN
    \
    --precision s \ $
    LINE_PROTOCOL_FILEPATH

Replace the following:

  • DATABASE_NAME: Name of the database to write to.
  • DATABASE_TOKEN: Database token with write permissions on the target database.
  • $LINE_PROTOCOL_FILEPATH: File path to the file containing the line protocol. Can be an absolute file path or relative to the current working directory.
cat 
$LINE_PROTOCOL_FILEPATH
| influxctl write \
--database
DATABASE_NAME
\
--token
DATABASE_TOKEN
\
--precision s \ -

Replace the following:

  • DATABASE_NAME: Name of the database to write to.
  • DATABASE_TOKEN: Database token with write permissions on the target database.
  • $LINE_PROTOCOL_FILEPATH: File path to the file containing the line protocol. Can be an absolute file path or relative to the current working directory.

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