Function Compute:Session lifecycle management

Core flow overview

1. Create a function and enable the session affinity feature.

2. Call the CreateSession API to create a session. To mount persistent storage for the session, add the nas_config parameter to the request.

3. When you call InvokeFunction, include the sessionId to route the request to the session instance with the associated storage.

4. As needed, call UpdateSession or DeleteSession to manage the session lifecycle.

Step 1: Enable session affinity

If you are creating or updating a function configuration, specify a Header Key, such as x-affinity-header-v1, to pass the SessionID. The following example describes how to update an existing function configuration:

1. Log on to the Function Compute console, and then click Function Management > Function List.

2. On the Function List page, click the name of the function that you want to configure to go to the function details page.

3. On the Configuration page, find Advanced Configuration, and click .

4. Turn on the Session Affinity switch, select HeaderField Affinity, and configure the Header Name, such as x-affinity-header-v1.

   Note

   The header name cannot start with the x-fc- prefix. It must start with a letter. Subsequent characters can be digits, hyphens (-), underscores (_), or letters. The name must be 5 to 40 characters long.

5. Click Deploy to complete the configuration update.

Step 2: Create a session resource

This topic uses the Python SDK as an example to show you how to create a session by calling the CreateSession - Create a session resource API.

1. Install SDK dependencies.

   macOS / Linux

   # Use pip3 to install
   pip3 install alibabacloud_fc20230330 alibabacloud_credentials alibabacloud_tea_openapi alibabacloud_tea_util
   
   # If you encounter permission issues, use the --user parameter
   pip3 install --user alibabacloud_fc20230330 alibabacloud_credentials alibabacloud_tea_openapi alibabacloud_tea_util
   
   # For macOS Homebrew Python environments, use --break-system-packages
   pip3 install --break-system-packages alibabacloud_fc20230330 alibabacloud_credentials alibabacloud_tea_openapi alibabacloud_tea_util

   Windows

   # Use pip to install
   pip install alibabacloud_fc20230330 alibabacloud_credentials alibabacloud_tea_openapi alibabacloud_tea_util
   
   # Or specify Python 3
   py -3 -m pip install alibabacloud_fc20230330 alibabacloud_credentials alibabacloud_tea_openapi alibabacloud_tea_util

2. Write the core code to create a session.

   Create a Python code file (for example, createSession.py). Copy the following code into the file and replace the core parameters.

   Core methods and parameters:

   • config.endpoint:

     • <Alibaba Cloud account ID>: Replace this with your Alibaba Cloud account ID.

     • <Endpoint>: For more information, see Function Compute 3.0 service area list. The format is fcv3.[region_id].aliyuns.com.

   • CreateSessionInput:

     • session_ttl_in_seconds: The total TTL of the session, in seconds.

     • session_idle_timeout_in_seconds: The light hibernation (formerly idle) timeout of the session, in seconds.

   • client.create_session_with_options: Replace <Your function name> with the name of the function for which you want to create the session.

   # -*- coding: utf-8 -*-
   from alibabacloud_fc20230330.client import Client as FC20230330Client
   from alibabacloud_credentials.client import Client as CredentialClient
   from alibabacloud_tea_openapi import models as open_api_models
   from alibabacloud_fc20230330 import models as fc20230330_models
   from alibabacloud_tea_util import models as util_models
   
   # 1. Create an account client.
   credential = CredentialClient()
   config = open_api_models.Config(credential=credential)
   config.endpoint = f'<Alibaba Cloud account ID>.<Endpoint>'
   client = FC20230330Client(config)
   
   # 2. Construct a CreateSession request.
   create_session_input = fc20230330_models.CreateSessionInput(
       session_ttlin_seconds=3600,
       session_idle_timeout_in_seconds=600
   )
   create_session_request = fc20230330_models.CreateSessionRequest(
       body=create_session_input
   )
   
   # 3. Send the request.
   runtime = util_models.RuntimeOptions()
   response = client.create_session_with_options('<Your function name>', create_session_request, {}, runtime)
   
   # 4. Get the sessionId from the response.
   print(response.body.to_map())
   session_id = response.body.session_id
   print(f"Session created successfully. Session ID: {session_id}")
   

Step 3: (Optional) Configure dynamic storage

1. Configure the function: To configure dynamic storage for a session, configure the function as follows:

   1. Instance Fencing: Go to the Configuration tab, navigate to Advanced Configuration > Instance Fencing, and select Session Fencing.

   2. Allow VPC Access:

      • Enable Allow VPC Access on the Configuration tab under Advanced Configuration > Network.

      • Set Configuration Method to Custom Configuration.

      • For VPC, select the VPC where the mount target is located.

2. Add the nas_config configuration: In the code from Step 2: Create a session resource, add the nas_config object using the following code. This object specifies the mount information and user identity.

   Core methods and parameters:

   Important

   You can configure dynamic NAS mounting for a session and NAS mounting for the function in the Configuration > Advanced Configuration > Storage settings at the same time. Note:

   • The User ID/Group ID defined in the following NASConfig must match the user (User ID) and user group (Group ID) used in the function mount configuration.

   • The same mount path (mount_dir) cannot be used for both dynamic session mounting and function mounting.

   • NASConfig: Configures the NAS file system and user identity. For example, you can assign an independent UID/GID to Tenant A.

     • NASMountConfig: The NAS mount configuration.

       • mount_dir: The mount path within the instance, such as /home/test.

       • server_addr: The address of the NAS file system and the tenant-specific subdirectory.

     • user_id: Specifies an independent POSIX User ID for this session.

     • group_id: Specifies an independent POSIX Group ID for this session.

# -*- coding: utf-8 -*-
from alibabacloud_fc20230330.client import Client as FC20230330Client
from alibabacloud_credentials.client import Client as CredentialClient
from alibabacloud_tea_openapi import models as open_api_models
from alibabacloud_fc20230330 import models as fc20230330_models
from alibabacloud_tea_util import models as util_models

# 1. Create an account client.
credential = CredentialClient()
config = open_api_models.Config(credential=credential)
config.endpoint = f'<Alibaba Cloud account ID>.<Endpoint>'
client = FC20230330Client(config)

# 2. Prepare the NAS mount configuration.
nas_mount_config = fc20230330_models.NASMountConfig(
    mount_dir='/mnt/data',  # The mount path within the instance
    server_addr='<YOUR-NAS-SERVER-ADDR>:/<tenant-a-path>'  # The address of the NAS file system and the tenant-specific subdirectory
)

# 3. Configure the NAS file system and user identity. For example, assign an independent UID/GID to Tenant A.
nas_config = fc20230330_models.NASConfig(
    mount_points=[nas_mount_config],
    user_id=1001,  # Specify an independent POSIX User ID for this session.
    group_id=1001  # Specify an independent POSIX Group ID for this session.
)

# 4. Construct a CreateSession request.
create_session_input = fc20230330_models.CreateSessionInput(
    nas_config=nas_config,
    session_ttlin_seconds=3600,
    session_idle_timeout_in_seconds=600
)
create_session_request = fc20230330_models.CreateSessionRequest(
    body=create_session_input
)

# 5. Send the request.
runtime = util_models.RuntimeOptions()
response = client.create_session_with_options('<Your function name>', create_session_request, {}, runtime)

# 6. Get the sessionId from the response.
print(response.body.to_map())
session_id = response.body.session_id
print(f"Session created successfully. Session ID: {session_id}")

Step 4: Run the code to create a session

1. Run the following commands to execute the code:

   export ALIBABA_CLOUD_ACCESS_KEY_ID=LTAI****************
   export ALIBABA_CLOUD_ACCESS_KEY_SECRET=<yourAccessKeySecret>
   python3 creatSession.py

   Parameters:

   • ALIBABA_CLOUD_ACCESS_KEY_ID: Specifies the AccessKey ID of your Alibaba Cloud account or RAM user.

   • ALIBABA_CLOUD_ACCESS_KEY_SECRET: Specifies the AccessKey secret of your Alibaba Cloud account or RAM user.

2. View the result.

   • Console output:

     {
       'containerId': 'c-********-********-************', 
       'createdTime': '2025-10-30T06:38:10Z', 
       'functionName': '****', 
       'lastModifiedTime': '2025-10-30T06:38:10Z', 
       'nasConfig': 
         {
           'groupId': 0, 
           'mountPoints': [
             {
               'enableTLS': False, 
               'mountDir': '/home/test', 
               'serverAddr': '*-*.*.nas.aliyuncs.com:/test'
                }
                  ], 
                  'userId': 0
                  }, 
        'qualifier': 'LATEST', 
        'sessionAffinityType': 'HEADER_FIELD', 
        'sessionId': '******************', 
        'sessionIdleTimeoutInSeconds': 600, 
        'sessionStatus': 'Active', 
        'sessionTTLInSeconds': 3600
        }
     Session created successfully. Session ID: ************

Step 5: Use a session to invoke a function

Call the InvokeFunction - Invoke a function API to invoke the function using a session.

Core code and description:

InvokeFunctionHeaders: Construct the request header to include the sessionId returned in the previous step. The value of the Header Key must match the value that you set in Step 1: Enable session affinity, such as x-affinity-header-v1, to enable session-bound routing.

# -*- coding: utf-8 -*-
from alibabacloud_fc20230330.client import Client as FC20230330Client
from alibabacloud_credentials.client import Client as CredentialClient
from alibabacloud_tea_openapi import models as open_api_models
from alibabacloud_fc20230330 import models as fc20230330_models
from alibabacloud_tea_util import models as util_models


# 1. Create an account client.
credential = CredentialClient()
config = open_api_models.Config(credential=credential)
config.endpoint = f'<Alibaba Cloud account ID>.<Endpoint>'
client = FC20230330Client(config)

# 2. Construct the request header. The Header Key ("x-affinity-header-v1") must be the same as the session affinity key configured for the function.
headers = fc20230330_models.InvokeFunctionHeaders(
    common_headers={
        "x-affinity-header-v1": 'session_id'
    }
)

# 3. Construct the invocation request. You can pass a body as needed.
invoke_request = fc20230330_models.InvokeFunctionRequest(
    body='your_request_payload'.encode('utf-8')  # Example payload
)

runtime = util_models.RuntimeOptions()

try:
    # 4. Send the invocation request.
    invoke_response = client.invoke_function_with_options(
        'your_function_name',
        invoke_request,
        headers,
        runtime
    )
    # 5. Process the response.
    print(f"Status Code: {invoke_response.status_code}")
    print(f"Response Body: {invoke_response.body.decode('utf-8')}")
except Exception as error:
    print(error.message)

What to do next: Update and delete a session

1. As needed, call UpdateSession - Update session configuration to extend the session validity period or perform other updates.

   Note

   After you pass `nas_config` in a `CreateSession` call, you cannot update the configuration using the `UpdateSession` API.

2. Call GetSession - Get session configuration information to retrieve the latest configuration information for the current session and confirm the update.

3. After the task is complete, call DeleteSession - Delete a session resource to release the session resources.