Erie

Erie is python daemon handling the incoming messages from multiple barcode scanners and send them to the printer.

Usage

This package is made to be ran as a daemon on the raspberry pi. The firmware with buildroot handle the build process and the configuration.

During development process launch the script can with the following command to log in the console.

> virtualenv venv
> source venv/bin/activate
> pip install -r requirements
> pip install -e .
> venv/bin/python erie -h
usage: [-h] [--no-daemon] [--logfile LOGFILE] [--debug] [--pid PID] [-c CONFIG]

optional arguments:
  -h, --help            show this help message and exit
  --no-daemon           Does not start the program as a daemon
  --logfile LOGFILE     Log destination
  --debug               Set the log level to show debug messages
  --pid PID             Pid destination
  -c CONFIG, --config CONFIG
                        Config file location
> venv/bin/python erie --no-daemon

In development mode its recommended to launch erie with the --debug option. The debug mode automatically handle the incoming data from the command line to avoid to have to use a barcode scanner to input data.

Config

The program is configurable by passing a .yaml file as argument (with .c argument) formatted in the following way:

despinassy:
    uri: <database uri>

erie:
    redis: <redis default channel>
    devices:
        - <device_name>:
            type: "serial"
            id:  <device_id in /dev/serial/by-id/>
            baudrate: <device baudrate>
            redis:  <device redis channel>
        - <device_name>:
            type: "evdev"
            id: <device_id in /dev/input/by-id/>

Commands

The program can detect formatted input commands scanned from a barcode scanner. The commands are prefixed with SPRTCHCMD: and have the following structure

SPRTCHCMD:<cmd_name>:<arguments>

There are two types of commands scannable.

• The one that change the mode the barcode scanner the command is scanned from, is operating in.
• The one that modify the result of the next scanned barcode.

Mode

The mode a barcode scanner is operating in define how the scanned barcode will be handled by the program. The mode of a scanner is changeable by scanning the following command with the scanner and is unique to each scanner device.

Print Mode: SPRTCHCMD:MODE:PRINT

In this mode the scanned barcodes will be directly sent to the printer through redis.

The print mode is the default mode.

Inventory Mode: SPRTCHCMD:MODE:INVENTORY

In this mode the scanned barcodes will get logged to the inventory table in the database. If the entry already exists in the database it will update the entry to increment the count.

Function

The 'function' category group all the commands that are gonna get queued and executed once the program receive a barcode.

Multiplier: SPRTCHCMD:MULTIPLIER:<multiplier>

Depending on the current mode the program is operating in, it will multiply the next action on a barcode (by default an action is applied 1 time) by the number passed in the argument of the command.

• In print mode, it will multiply the number of barcode that get printed.
• In inventory mode, it will multiply the number time we log the next barcode.

This command can get stacked before being executed once a barcode is received. Scanning the command SPRTCHCMD:MULTIPLIER:2 and then SPRTCHCMD:MULTIPLIER:3 will apply the next action 6 time.

Clear: SPRTCHCMD:CLEAR:0

Clear the queued functions.

Useful Links

• LS3578Product Reference Guide
• Product reference guide