Use TagHub SDK on Hello World Application 1-python3.md

Use TagHub SDK on Hello World Application 1

Document Version: V1.0

Change Log

Version	Date	Content
1.0	2022-02-10	Document created

Purpose

This document guide you how to use TagHub Python SDK on Hello World Application to publish Tag data.

You shall complete pre-request steps:

• Build and Run "Hello World" Application.
• Invoke ThingsPro Edge API on Hello World Application

---

1. Modify Python Code

1.1 Add Python packages

import os, requests, time, json
from thingspro.edge.tag_v1 import tag

• thingspro.edge.tag_v1 is TagHub Python SDK.

1.2 Define Tag Publisher

_publisher = tag.Publisher()

• We will use _publisher to update Tag value.

1.3 Define a method to Create a Virtual Tag via ThingsPro Edge Restful API

#post /api/v1/hello-world/tag
@app.route('/api/v1/hello-world/tag', methods=['POST'])
def post_tag():
    newTag = request.json    
    if ('prvdName' in newTag) and ('srcName' in newTag) and ('tagName' in newTag) and ('dataType' in newTag):    
        try:
            result = call_API('get', '/tags/list?provider='+newTag['prvdName'], None)
            messageJson = json.loads(result["message"])
            if "data" in messageJson:
                tagList = messageJson["data"]            
                for tag in tagList:
                    if (tag['srcName'] == newTag['srcName']) and (tag['tagName'] == newTag['tagName']):
                        return "OK"         # Tag already there, return            
            # Create Tag
            postTag = {
                'prvdName': newTag['prvdName'],
                'srcName': newTag['srcName'],
                'tagName': newTag['tagName'],            
                'dataType': newTag['dataType'],
                'access': 'rw'
            }    
            result = call_API('post', '/tags/virtual', postTag)
            return 'OK'
        except Exception as e:
            return str(e) 
    else:
        return "Bad payload."

• Before update writable tags, this method allow us to create virtual tags by Restful API.

1.4 Define a method to Update a Virtual Tag Value via TagHub Python SDK

#put /api/v1/hello-world/tag
@app.route('/api/v1/hello-world/tag', methods=['PUT'])
def put_tag():
    newTagValue = request.json
    if ('prvdName' in newTagValue) and ('srcName' in newTagValue) and ('tagName' in newTagValue) and ('dataValue' in newTagValue) and ('dataType' in newTagValue):
        timestamp=int(time.time()*1000000)
        try:
            tagValue = {
                'prvdName': newTagValue['prvdName'],
                'srcName': newTagValue['srcName'],
                'tagName': newTagValue['tagName'],            
                'dataValue': newTagValue['value'],
                'dataType': newTagValue['dataType'],
                'ts': timestamp        
            }    
            _publisher.publish(tagValue)  
            return 'OK'
        except Exception as e:
            return str(e)    
    else:
        return "Bad payload."

• _publisher.publish() will update Tag's value.

2. Develop Your Application

2.1 Download Hello World Application 1.2

$ wget https://tpe2.azureedge.net/Python3/HelloWorldApp12.tar

2.2 ThingsPro Edge Application 1.2 Structure

Name	Type	Note
Dockerfile	File	Same with 1.0
app	Folder	Update with TagHub SDK code
docker-compose.yml	File	Update version to 1.2
metadata.yml	File	Update version to 1.2
nginx.conf	File	Same with 1.0
requirements.tx	File	Update required packages for TagHub SDK

2.3 Build ThingsPro Edge Applicaiton

Follow pre-request step: Build and Run "Hello World" Application, to build hello-world application V1.2

drwxrwxrwx 2 root root      4096 Feb 12 15:28 app
-rwxrwxrwx 1 root root        56 Feb 12 08:46 docker-compose.yml
-rwxrwxrwx 1 root root       851 Feb 12 15:35 Dockerfile
-rw-r--r-- 1 root root 136970240 Feb 12 16:11 hello-world_1.2_armhf.mpkg
-rwxrwxrwx 1 root root       107 Feb 12 08:46 metadata.yml
-rwxrwxrwx 1 root root       281 Feb 12 08:46 nginx.conf
-rwxrwxrwx 1 root root        73 Feb 12 13:07 requirements.txt

3. Deploy Application on Moxa IIoT Gateway

3.1 Deploy hello-world V1.2

Follow pre-request step: Build and Run "Hello World" Application, to deploy hello-world application V1.2

3.2 Testing

3.2.1 Create two new virtual tags by POST /api/v1/hello-world/tag

curl -X POST https://127.0.0.1:8443/api/v1/hello-world/tag -H "mx-api-token:$(cat /var/thingspro/data/mx-api-token)" -H "Content-Type:application/json" -k -d '{"prvdName":"virtual","srcName":"hello-world","tagName":"tag01", "dataType":"string"}'

curl -X POST https://127.0.0.1:8443/api/v1/hello-world/tag -H "mx-api-token:$(cat /var/thingspro/data/mx-api-token)" -H "Content-Type:application/json" -k -d '{"prvdName":"virtual","srcName":"hello-world","tagName":"tag02", "dataType":"int32"}'

3.3.2 Update virtual tags value by PUT /api/v1/hello-world/tag

curl -X PUT https://127.0.0.1:8443/api/v1/hello-world/tag -H "mx-api-token:$(cat /var/thingspro/data/mx-api-token)" -H "Content-Type:application/json" -k -d '{"prvdName":"virtual","srcName":"hello-world","tagName":"tag01", "dataValue":"Hello World", "dataType":"string"}'

curl -X PUT https://127.0.0.1:8443/api/v1/hello-world/tag -H "mx-api-token:$(cat /var/thingspro/data/mx-api-token)" -H "Content-Type:application/json" -k -d '{"prvdName":"virtual","srcName":"hello-world","tagName":"tag02", "dataValue":4040, "dataType":"int32"}'

3.2.3 Monitor these two virtual tags on ThingsPro Edge Web Admin

ThingsPro Edge Web Admin / Tag Management offers a easy way to monitor Tag value changed.

This feature is available on ThingsPro Edge V2.2.1+.

3.3 Done and Next Action

• Use TagHub SDK on Hello World Application 2