SDK for Python

Last updated: 2020-01-08 19:26:47

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Tencentserverless SDK Overview

Tencentserverless is a Tencent Cloud SCF SDK that integrates SCF business flow APIs to make it easier to invoke SCF functions. It allows users to invoke a function quickly from a local system, CVM instance, container or function, eliminating the need to encapsulate APIs in a public cloud.

Features

Tencentserverless SDK has the following features:

  • It can invoke functions in a high-performance, low-latency manner.
  • It enables quick invocation across functions after the required parameters are entered (it will obtain parameters in environment variables by default, such as region and secretId).
  • It supports access with private network domain names.
  • It supports session keep-alive.
  • It supports cross-region function invocation.
  • It supports native invocation methods in Python.

Quick Start

Chaining functions

Example

  • To chain functions in different regions, you must specify regions. For naming rules, see Region List.
  • If no region is specified, functions will be chained within the same region by default.
  • If no namespace is specified, default will be used by default.
  1. Create a to-be-invoked Python function named "FuncInvoked" in the cloud in the region of Guangzhou. The content of the function is as follows:
# -*- coding: utf8 -*-
def main_handler(event, context):
    if 'key1' in event.keys():
        print("value1 = " + event['key1'])
    if 'key2' in event.keys():
        print("value2 = " + event['key2'])
    return "Hello World from the function being invoked"  #return
  1. Create an invoking Python function named "PythonInvokeTest" in the cloud in the region of Chengdu. You can edit the function as needed following two methods:
    Method 1: If you do not need to invoke the function frequently, you can use the sample code below:
# -*- coding: utf8 -*-
from tencentserverless.scf import Client
from tencentserverless.exception import TencentServerlessSDKException
from tencentcloud.common.exception.tencent_cloud_sdk_exception import TencentCloudSDKException

def main_handler(event, context):
    print("prepare to invoke a function!")

    try:
        data = scf.invoke('FuncInvoked',region="ap-guangzhou",data={"a": "b"})
        print (data)
    except TencentServerlessSDKException as e:
        print (e)
    except TencentCloudSDKException as e:
        print (e)
    except Exception as e:
        print (e)
    return "Already invoked a function!" # return

The output is as follows:

"Already invoked a function!"

Method 2: If you need to invoke the function frequently, you can connect to and trigger it via a client with the following sample code:

# -*- coding: utf8 -*-
from tencentserverless.scf import Client
from tencentserverless.exception import TencentServerlessSDKException
from tencentcloud.common.exception.tencent_cloud_sdk_exception import TencentCloudSDKException

def main_handler(event, context):
    scf = Client(region="ap-guangzhou")

    print("prepare to invoke a function!")
    try:
        data = scf.invoke('FuncInvoked',data={"a": "b"})
        # data = scf.FuncInvoked(data={"a": "b"}) # To use the native invocation method in Python, you need to first perform initialization via the client
        print (data)
    except TencentServerlessSDKException as e:
        print (e)
    except TencentCloudSDKException as e:
        print (e)
    except Exception as e:
        print (e)
    return "Already invoked a function!" # return

The output is as follows:

"Already invoked a function!"

Invoking a function locally

Preparing for development

  • Development environment
    Python 2.7 or Python 3.6 has been installed.
  • Operating environment
    Windows, Linux, or macOS with tencentserverless SDK installed.

The above development preparations must be completed before functions can be invoked locally. We recommend you upload a function to the cloud after it is developed locally to debug it via chaining functions.

Installing via pip (recommended)

Run the following command to install tencentserverless SDK for Python.

pip install tencentserverless

Installing via source package

Go to the GitHub code hosting page to download the latest source package, decompress it, and run the following commands in sequence to install.

cd tencent-serverless-python
python setup.py install

Configuring tencentserverless SDK for Python

Run the following command to upgrade tencentserverless SDK for Python.

pip install tencentserverless -U

Run the following command to view the information of tencentserverless SDK for Python.

pip show tencentserverless

Example

  1. Create a to-be-invoked Python function named "FuncInvoked" in the cloud in the region of Guangzhou. The content of the function is as follows:
# -*- coding: utf8 -*-
def main_handler(event, context):
    if 'key1' in event.keys():
        print("value1 = " + event['key1'])
    if 'key2' in event.keys():
        print("value2 = " + event['key2'])
    return "Hello World from the function being invoked"  #return
  1. Create a local file named PythonInvokeTest.py with the following content:
# -*- coding: utf8 -*-
from tencentserverless.scf import Client
from tencentserverless.exception import TencentServerlessSDKException
from tencentcloud.common.exception.tencent_cloud_sdk_exception import TencentCloudSDKException

def main_handler(event, context):
    print("prepare to invoke a function!")
    scf = Client(secret_id="AKIxxxxxxxxxxxxxxxxxxxxxxggB4Sa",secret_key="3vZzxxxxxxxxxxxaeTC",region="ap-guangzhou")# Replace with your own secret_id and secret_key
    try:
        data = scf.invoke('FuncInvoked',data={"a":"b"}) 
        # data = scf.FuncInvoked(data={"a":"b"}) 
        print (data)
    except TencentServerlessSDKException as e:
        print (e)
    except TencentCloudSDKException as e:
        print (e)
    except Exception as e:
        print (e)
    return "Already invoked a function!" # return

main_handler("","")

secret_id and secret_key: Secret ID and secret key of TencentCloud API. You can obtain them or create news ones by logging into the CAM Console and selecting TencentCloud API Key > API Key Management.

Go to the directory where the PythonInvokeTest.py file is located and run the following command to view the result.

python PythonInvokeTest.py

The output is as follows:

prepare to invoke a function!
"Hello World form the function being invoked"

API List

API Reference

Client

Method:

  • __init__

    Parameter information:

    Parameter Name Required Type Description
    region No String Region information, which is the same as the region where the function invocation resides by default. The region is Guangzhou by default for local invocation.
    secret_id No String secret_id, which is obtained from the function's environment variable by default and is required for local invocation.
    secret_key No String secret_key, which is obtained from the function's environment variable by default and is required for local invocation.
    token No String Token, which is obtained from the function's environment variable by default.
  • invoke

    Parameter information:

    Parameter Name Required Type Description
    function_name Yes String Function name.
    qualifier No String Function version. Default value: $LATEST.
    data No Object Input parameter for function execution, which must be an object that can be converted by json.dumps.
    namespace No String Namespace. Default value: default.

invoke

This is used to invoke a function. Currently, only sync invocation is supported.

Parameter information:

Parameter Name Required Type Description
region No String Region information, which is the same as the region where function invocation resides by default. The region is Guangzhou by default for local invocation.
secret_id No String secret_id, which is obtained from the function's environment variable by default and is required for local invocation.
secret_key No String secret_key, which is obtained from the function's environment variable by default and is required for local invocation.
token No String Token, which is obtained from the function's environment variable by default.
function_name Yes String Function name.
qualifier No String Function version. Default value: $LATEST.
data No String Input parameter for function execution, which must be an object that can be converted by json.dumps.
namespace No String Namespace. Default value: default.

TencentserverlessSDKException

Attributes:

  • [code]
  • [message]
  • [request_id]
  • [response]
  • [stack_trace]

Methods and descriptions:

Method Name Description
get_code Returns the error information
get_message Returns the error information
get_request_id Returns request_id information
get_response Returns response information
get_stack_trace Returns stack_trace information