Session lifecycle management

Workflow overview

1. Create a function and enable session affinity.

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 calling InvokeFunction, include the sessionId to route the request to the instance bound to that session.

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

Step 1: Enable session affinity

When you create a function or update a function configuration, enable session affinity. For HeaderField affinity, you need to specify a header key, such as x-affinity-header-v1, to pass the session ID. The following example shows how to update an existing function configuration:

1. Log on to the Function Compute console and click Function Management > Functions.

2. On the Functions page, click the name of the function you want to configure to open its details page.

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

4. Turn on the Session Affinity switch, select HeaderField affinity, and configure the Header Name, for example, 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 apply the configuration update.

Step 2: Create a session

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

1. Install the SDK dependencies.

   macOS / Linux

   # Install by using pip3
   pip3 install alibabacloud_fc20230330 alibabacloud_credentials alibabacloud_tea_openapi alibabacloud_tea_util
   
   # If you encounter a permission issue, 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

   # Install by using pip
   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 file, such as createSession.py. Copy the following code into the file and replace the core parameters with your actual values.

   Core methods and parameters:

   • config.endpoint:

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

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

   • CreateSessionInput:

     • session_ttl_in_seconds: The total time-to-live of the session, in seconds.

     • session_idle_timeout_in_seconds: The light hibernation timeout of the session, in seconds.

   • client.create_session_with_options: Replace <Function_Name> with the name of the function for which you want to create a 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'<Account_ID>.<Endpoint>'
   client = FC20230330Client(config)
   
   # 2. Construct a CreateSession request.
   create_session_input = fc20230330_models.CreateSessionInput(
       session_ttl_in_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('<Function_Name>', create_session_request, {}, runtime)
   
   # 4. Get the session ID 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, you must configure the function as follows:

   1. Instance isolation: On the Configuration tab, navigate to Advanced Settings > Instance isolation, and select Session Isolation.

   2. Access to VPC:

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

      • Set Configuration Mode 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, add the nas_config object to specify the mount information and user identity by referring to the following code.

   Core methods and parameters:

   Important

   You can dynamically mount a NAS file system for a session and mount a NAS file system in the Configuration > Advanced Settings > Storage settings of the function at the same time. Note the following points:

   • The user ID/group ID defined in the NASConfig object below must be the same as the user ID and group ID used in the function's mount configuration.

   • The same mount path (mount_dir) cannot be shared between dynamic session mounting and the function's static mount configuration.

   • NASConfig: Configures the NAS file system and user identity. For example, assign a unique 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'<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 a unique 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_ttl_in_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('<Function_Name>', create_session_request, {}, runtime)

# 6. Get the session ID 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 createSession.py

   Parameters:

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

   • ALIBABA_CLOUD_ACCESS_KEY_SECRET: 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: Invoke a function with a session

Call the InvokeFunction API to invoke the function by using a session.

Core code example and description:

InvokeFunctionHeaders: Constructs the request header to include the sessionId returned in the previous step. The header key, such as x-affinity-header-v1, must match the Header Name that you configured in Step 1: Enable session affinity. This implements 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'<Account_ID>.<Endpoint>'
client = FC20230330Client(config)

# 2. Construct the request header. The Header Name ("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')  # An 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)

Next steps: Update and delete a session

1. As needed, call 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 by using UpdateSession.

2. Call Get session configuration to get the latest configuration of the current session and confirm the update.

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