Quick Start

This guide will run through the installation and configuration of the data logging daemon service.

Installation

Note

pip3 and python3 are used here because currently pip and python refer to python2 versions on some common Linux distributions such as Ubuntu. On Windows, or distributions like Arch where python3 is the default, pip and python may be used instead.

Note

These instructions assume a system-wide install, which requires root or administrator privileges. On Linux, either first switch to a root login with sudo -i, or prefix all commands with sudo. Alternatively, a user-level install can be performed by using the --user flag on pip or systemd commands, for example pip3 install --user ..., or systemctl --user ...

Ensure the pip python package manager is installed. For example:

# Debian, Ubuntu etc.
apt install python3-pip
# Arch Linux
pacman -Sy python-pip

Install using pip:

pip3 install --upgrade datalogd

Some plugins require additional packages. These will be listed when the plugin is attempted to be loaded. The optional dependencies can be also be installed with pip, for example:

pip3 install --upgrade pyserial pyserial-asyncio PySensors influxdb matplotlib

The executable should now be available. This will show the available command line parameters:

datalogd --help

On Linux operating systems, a systemd service file will be installed and enabled to run on startup. Automatic configuration to start on alternate operating systems (such as Windows) is not yet implemented, and therefore must be done manually. Once the configuration file has been prepared, the service can be started with systemctl start datalog.

Windows

There are several ways of getting the service to run automatically at startup. This is one example which can be configured as a standard user without admin privileges.

• Get the the datalogd.xml file and save it somewhere.
• Open Task Scheduler (windows key, type taskschd.msc, enter).
• Click Action->Import Task..., find and select the datalogd.xml file.
• Click Change User or Group... button, type your user name, click Check Names, then OK, and OK.

Configuration

The default configuration has no function, and so will not run. Configuring the daemon is performed by either creating or editing a configuration file, or passing parameters on the command line.

Configuration Files

To obtain the location of the default configuration files, run with the --show-config-dirs command line option.

datalogd --show-config-dirs

INFO:main:Default configuration file locations are:
  /etc/xdg/datalogd/datalogd.conf
  /root/.config/datalogd/datalogd.conf

All config files will be read, with any options in the later files overriding the earlier ones. Note also that a custom config file may be specified on the command line, and will be read last. Configuration specified as command line parameters will override any configuration read from files.

A configuration file should take the form of:

[datalogd]

plugin_paths = []

connection_graph =
  digraph {
    source [class=NullDataSource];
    sink [class=NullDataSink];
    source -> sink;
  }

The options are:

• plugin_paths - path(s) to directories containing custom source/filter/sink plugins. See the Plugins section for details on creating custom plugins.
• connection_graph - declaration of plugin nodes, parameters, and the connections between them. See the Connection Graph section for details on the connection graph syntax.

Command Line Parameters

datalogd --help

usage: datalogd [-h] [-c FILE] [-p DIR [DIR ...]] [-g GRAPH_DOT] [--show-config-dirs]

Run the data logging daemon service.

optional arguments:
  -h, --help            show this help message and exit
  -c FILE, --configfile FILE
                        Path to configuration file.
  -p DIR [DIR ...], --plugindirs DIR [DIR ...]
                        Directories containing additional plugins.
  -g GRAPH_DOT, --graph-dot GRAPH_DOT
                        Connection graph specified in DOT format.
  --show-config-dirs    Display the default locations of configuration files, then exit.