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Python Development

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Description

Apex has integrated python 3.7 with which you can integrate your own applications.

# Example:
syrus4g@syrus-867698040023502 ~ 
$ python3
Python 3.7.7 (default, Mar  7 2022, 21:29:46) 
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> print ( os.getcwd() )
/data/users/syrus4g
>>> exit()
syrus4g@syrus-867698040023502 ~

Package Installation

To start using Python to develop applications you'll want to add pip to install python packages. To do this you need to add the 'dev_repo' on the device using the apx-core tool.

sudo apx-core add_dev_repo

And then install the python package installer, this will take a few minutes

sudo apx-core install python3-pip

Once that's done you can install packages with the following command:

pip3 install <PACKAGE_NAME> --user

Example use of requests package:

# Example
pip3 install requests --user

# Example
$ python3
>>> import requests
>>> x = requests.get('https://w3schools.com/python/demopage.htm')
>>> print(x.text)
<!DOCTYPE html>
<html>
<body>

<h1>This is a Test Page</h1>

</body>
</html>
>>>

Apex Message Broker & Database

Apex runs two Redis instances that can be used as message brokers or databases, the first one (User Application Redis) runs on the default port 6379 and the second one (System/Core Redis) is dedicated to Apex core applications and runs on port 7480.

Usage

# Example
pip3 install redis --user

System-Core Instance

This is a simple example of how to use the System-Core Redis instance to work with the database (GET, HGET, HGETALL, LRANGE) or the message broker (PSUBSCRIBE, SUBSCRIBE, MONITOR) for consults in your applications.

You can download and run some examples from here: Apex Core Python Examples

To see what data is available in APEX for your request, please go to Apex Message Broker & Database

Database consult example:
import redis

# Create a connection to the Redis server
redis_host = 'localhost'  
redis_port = 7480        
redis_password = None    

# Create a Redis client
redis_client = redis.StrictRedis(host=redis_host, port=redis_port, password=redis_password, decode_responses=True)

# Testing GET command:

# GET: Retrieve and print the value of previous key
value = redis_client.get('network_interface')
print(f"Network Interface: {value}")
Message Broker listener example:
import redis
from time import sleep

# Create a connection to the Redis server
redis_host = 'localhost'  
redis_port = 7480         
redis_password = None

# Initialize redis connection
r = redis.StrictRedis(host=redis_host, port=redis_port, password=redis_password)
p = r.pubsub()

# To subscribe to one o multiple channels.
# In this case we will to subscribe to the interface pattern channel here you will receive 
# all related to the I/O's

p.psubscribe("interface/*")

# Main loop function.
while True:
  message = p.get_message()
  if message:
    print(f"Channel: {message['channel']}, Received message: {message['data']}")
  sleep(0.01)

User Instance

This is a simple example of how to use the User Redis instance to work with the database (GET, SET, HGET,...) or the message broker (PUBLISH, PSUBSCRIBE,...) in your applications.

You can download and run some examples from here: Apex User Python Examples

Database consult example:
import redis
from time import time

# Create a connection to the Redis server
redis_host = 'localhost'  
redis_port = 6379         
redis_password = None  

# Create a Redis client
redis_client = redis.StrictRedis(host=redis_host, port=redis_port, password=redis_password, decode_responses=True)

# Testing SET & GET commands:
# SET
current_time = str(int(time()))
redis_client.set('last_request_time', current_time)

# GET: Retrieve and print the value of previous key
value = redis_client.get('last_request_time')
print(f"Storing last request time: {value}")
Message Broker publish example:
import redis
from time import sleep, time

# Create a connection to the Redis server
redis_host = 'localhost'  
redis_port = 6379         
redis_password = None  

# Create a Redis client for publishing
redis_publisher = redis.StrictRedis(host=redis_host, port=redis_port, password=redis_password)

# Publish messages to the channel
channel = 'notification/request'

for x in range(3):
  current_time = str(int(time()))
  message = "New request at " + current_time
  print(f"Publish: {message}")
  redis_publisher.publish(channel, message)  
  sleep(2)

Apex System Tool Execution

You can use the package os to run apx commands or system-tools on the device.

import time
import os

# Send a message to a SyrusJS instance to set a variable
os.system("syrus-apps-manager send-message __cloud_syrusjs "set variable var_foo 1")

# Get the current time as a timestamp
current_timestamp = int(time.time())

# Format your command with the new timestamp
command = f"sudo apx-video create_clip --name={current_timestamp}_crash --time_win=-7,+7"

# Execute the command
os.system(command)

Build APEX Application

To build an application to be executed in apex you must create a compressed file as .zip in which you must add the following files, the binary or executable of your application, in the case the .py, a package.json file with the description of the application and an init.sh file that will have the definition of how your application will be executed.

Example s4test_app.zip content:

  • init.sh
  • package.json
  • myapp.py

🚧

Make sure init.sh is executable

Before uploading an application to the Syrus 4, make sure the file init.sh is executable so that the Syrus 4 default user can execute it.

This command is executed locally on your computer outside of the Syrus 4, before the file is compressed.

# Make file executable with chmod command
chmod +x init.sh

The following is a basic example of the content that these files should contain:

init.sh

python3 test.py

package.json

{
  "name": "myapp",
  "version": "0.1.1",
  "description": "My App application",
  "icon": "https://myicons.com/logo.png",
  "minApexVersion": "23.11.1",
  "repository": "https://myrepo.com/applications/mmyApp/",
  "author": "[email protected]"
}

test.py

print("Hello World")

Check applications state

If you need to consult if your app is running, installed, within an instance run any of this command from cloud or console.

Running apps

syrus-apps-manager get-running

Installed apps

syrus-apps-manager list-apps

App within an instance

syrus-apps-manager list-instances

Install & Run your Applications

To install and run your applications you need to use the apex tool syrus-apps-manager or the Management Tool as follows:

Option 1: Syrus Cloud (Recomended)

Once you are logged in the Syrus Cloud go to Applications -> Applications Tap

Click on Define Instance

Click on Application File and upload your myapp.zip

Change the instance name and complete the other fields if you want (Optional).

Add the devices to this instance and save, the application will run automatically.

Option 2: syrus-apps-manager

Copy your "myapp.zip" file to the Syrus4G device using SSH or Syrus Cloud.

Run 

syrus-apps-manager install-app path_to_your_app

# Example
syrus-apps-manager install-app /data/users/syrus4g/myapps/myapp.zip

Run

syrus-apps-manager create-instance instace_name app_name app_version

# Example 
syrus-apps-manager create-instance myinstace myapp 1.0.0

Run

syrus-apps-manager start instace_name

# Example 
syrus-apps-manager start myinstace

Option 2: Management Tool

Once logged into the Management Tool go to Applications Manager

Click on ADD NEW APP and browse for the .zip file on your computer.

Click on INSTALL

Click on the installed app and click on create instance and set the instance name.

Once the instance is created click on the three points icon and start the instance.

Updated 6 months ago