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Instream

InfluxDB driver for Elixir

InfluxDB Support

Tested InfluxDB versions:

  • 1.7.11
  • 1.8.10
  • 2.0.9
  • 2.1.1
  • 2.2.0

Package Setup

To use Instream with your projects, edit your mix.exs file and add the required dependencies:

defp deps do
  [
    # ...
    {:instream, "~> 2.0"},
    # ...
  ]
end

Testing

To run the tests you need to have HTTP authentication enabled.

The following environment variables are used to select some test suites and the InfluxDB version under test:

  • INFLUXDB_VERSION: one of "1.7", "1.8", "2.0", "2.1", or "2.2"
  • INFLUXDB_PORT_UDP: the UDP port used for writer testing (InfluxDB 1.x only)
  • INFLUXDB_SOCKET: path to the InfluxDB unix socket (InfluxDB 1.8 only)
  • INFLUXDB_TOKEN: the authentication token used (InfluxDB 2.x only)

Usage

Connections

To connect to an InfluxDB server you need a connection module:

defmodule MyConnection do
  use Instream.Connection, otp_app: :my_app
end

The :otp_app name and the name of the module can be freely chosen but have to be linked to a corresponding configuration entry. This defined connection module needs to be hooked up into your supervision tree:

children = [
  # ...
  MyConnection,
  # ...
]

Example of the matching configuration entry:

# InfluxDB v2.x
config :my_app, MyConnection,
  auth: [method: :token, token: "my_token"],
  bucket: "my_default_bucket",
  org: "my_default_org",
  host: "my.influxdb.host",
  version: :v2

# InfluxDB v1.x
config :my_app, MyConnection,
  auth: [username: "my_username", password: "my_password"],
  database: "my_default_database",
  host: "my.influxdb.host"

More details on connections and configuration options can be found with the Instream.Connection and Instream.Connection.Config modules.

Queries

# Flux query
MyConnection.query(
  """
    from(bucket: "#{MyConnection.config(:bucket)}")
    |> range(start: -5m)
    |> filter(fn: (r) =>
      r._measurement == "instream_examples"
    )
    |> first()
  """
)

# InfluxQL query
MyConnection.query("SELECT * FROM instream_examples")

A more detailed documentation on queries (reading/writing/options) is available in the documentation for the modules Instream and Instream.Connection.

Series Definitions

If you do not want to define the raw maps for writing data you can pre-define a series for later usage:

defmodule MySeries do
  use Instream.Series

  series do
    measurement "my_measurement"

    tag :bar
    tag :foo

    field :value
  end
end

More information about series definitions can be found in the module documentation of Instream.Series.

Writing Series Points

You can then use this module to assemble a data point (one at a time) for writing:

data = %MySeries{}
data = %{data | fields: %{data.fields | value: 17}}
data = %{data | tags: %{data.tags | bar: "bar", foo: "foo"}}

And then write one or many at once:

MyConnection.write(point)
MyConnection.write([point_1, point_2, point_3])

License

Apache License, Version 2.0