Function Compute:Configure an OSS File System

Step 1: Configure an OSS Mount Point

In Function Compute, OSS is configured at the service level. This means that after you configure an OSS mount target for a service, all functions in that service can access files in the specified OSS bucket.

1. Log on to the Function Compute console. In the left-side navigation pane, click Services & Functions.

2. In the top navigation bar, select a region. On the Services page, find the desired service and click Configure in the Actions column.

3. On the Edit Service page, configure the following parameters in the Storage Configuration section, and then click Save.

   Configuration Item	Description	Example
   Mount OSS	Enable or disable the OSS file system. Enable: Enable the OSS file system. Disable: Disable the OSS file system.	Enable
   OSS Mount Point: Configure the following settings for the OSS mount point.
   Bucket	Select an existing OSS bucket. To create a new bucket, click Create New OSS Bucket below. This opens the Object Storage Service console, where you can create one manually. For pricing details, see OSS Billing Overview.	example-bucket
   Bucket Subdirectory	Set a subdirectory in the bucket. Use an absolute path. Leave this blank or set it to / to mount the bucket root directory.	/files
   OSS Endpoint	After you select a bucket, the default endpoint for that bucket appears. You can choose Custom Endpoint to change it. For endpoints by region, see Regions and Endpoints. Note If you select a Bucket in the same region as the Function Compute service, we recommend that you use the OSS internal network endpoint. If the bucket is in a different region, use the public network endpoint. This incurs outbound traffic fees over the Internet.	Default address
   Local Directory in Function	Set a local directory in the function runtime environment. The path must be a subdirectory of /home, /mnt, or /data. Note You do not need to create this directory manually. It is ready to use after you set it.	/mnt/oss
   Local Directory Permissions in Function	Set read-only or read-write permissions for the mounted directory in the function runtime environment.	Read-write

   Note

   OSS mounting depends on the network configuration of your service. If your service allows access only from a VPC (Allow Function Invocation Only from Specified VPC is set to Yes and Allow Function to Access the Internet is set to No) and you use a public network endpoint, you must ensure that your function can access the Internet through the specified VPC. For more information, see Configure a Static Public IP Address.

Step 2: Create a Function and Access Files in the Mounted OSS Directory

After you configure the OSS mount point, you can access files in the mounted directory as if they were local files.

1. On the Create Function page, configure the following settings. Keep other settings at their default values, and then click Create.

   • Creation Method: Create with Built-in Runtimes.

   • Basic Settings: Enter a Function Name. For Handler Type, select Event Handler.

   • Function Code: For Runtime, select Python 3.10. For Code Upload Method, select Sample Code.

2. On the function details page, click the Function Code tab. In the code editor, enter your code and then click Deploy Code.

   This example uses Python. The following code provides an example.

   import os
   
   
   def handler(event, context):
       # Mounted directory
       mount_path = '/mnt/oss'
       
       # List files in the mounted directory
       files = os.listdir(mount_path)
       print("Files in OSS mount:", files)  
       # Read a file in the mounted directory
       file_path = os.path.join(mount_path, 'example.txt')
       if os.path.exists(file_path):
           with open(file_path, 'r') as file:
               content = file.read()
               print("Content of example.txt:", content)
       else:
           print("example.txt does not exist.")
       # Write a file to the mounted directory
       write_path = os.path.join(mount_path, 'output.txt')
       with open(write_path, 'w') as file:
           file.write("Hello, OSS mount!")
           print("Wrote to output.txt in OSS mount.")
       
       return "Function execution completed."
     

   Note

   In the code, replace example.txt with the actual name of a file in your mounted OSS directory.

3. After the code is deployed, click Test Function on the Function Code tab.

   After the function is executed, you can view the result below the Function Code tab. On the Logs tab, you can view the content of example.txt from the mounted OSS directory. In the OSS console, you can view the content of output.txt that is written to the mounted directory.

Verify the storage class of your OSS bucket. Files in buckets that use the Archive or Cold Archive storage class are frozen. You must restore these files before you can access them. We recommend that you use the Standard storage class for your OSS bucket.