[Bug] POST `/api/open/policy` Fails with `internal-error` Due to FSL Compilation Failure in `safeline-mgt`

What happened?

When sending a POST request to https://localhost:9443/api/open/policy to create a new policy, the API returns an internal-error response with the message "compiling failed: compiling FSL failed". The GET request to the same endpoint succeeds, indicating the API is accessible, but the POST operation fails. The error is logged in the safeline-mgt container, pointing to an issue with FSL (Filter Specification Language) compilation in the fvm service.

How we reproduce?

1. Set up the environment using the provided docker-compose.yml and .env files:
   • .env:

     SAFELINE_DIR=./data/safeline
     IMAGE_TAG=latest
     MGT_PORT=9443
     POSTGRES_PASSWORD=xxx
     SUBNET_PREFIX=172.22.222
     IMAGE_PREFIX=chaitin
     ARCH_SUFFIX=
     RELEASE=
     REGION=-g
     

   • Relevant docker-compose.yml services: safeline-mgt, safeline-fvm, safeline-pg (full configuration provided in the original context).
2. Start the services:

   docker-compose up -d
   

3. Verify the safeline-mgt service is running by sending a GET request:

   curl -k https://localhost:9443/api/open/policy -H "X-SLCE-API-TOKEN: Your API Token"
   

   This should return a successful response.
4. Send a POST request to create a policy:

   curl -k -X POST https://localhost:9443/api/open/policy \
   -H "Content-Type: application/json" \
   -H "X-SLCE-API-TOKEN: Your API Token" \
   -d '{
       "name": "IPBlock",
       "is_enabled": true,
       "pattern": [
           [
               {
                   "k": "src_ip",
                   "op": "in",
                   "v": [
                       "172.19.0.1"
                   ],
                   "sub_k": ""
               }
           ]
       ],
       "action": 1,
       "expire": 174854302,
       "log": true,
       "level": 0
   }'
   

5. Observe the response and check the safeline-mgt container logs:

   docker logs safeline-mgt
   

Expected behavior

The POST request to /api/open/policy should successfully create the policy and return a success response (e.g., HTTP 200 or 201 with a confirmation message, such as {"data": {...}, "msg": "success"}).

Error log

The safeline-mgt container logs show the following errors:

safeline-mgt  | 2025/05/29 10:42:18 [ERROR] fvm fvm/grpc_helper.go:76 FVM AppendFSL Close Error rpc error: code = Unknown desc = compiling failed: compiling FSL failed
safeline-mgt  | 2025/05/29 10:42:18 [ERROR] fvm fvm/grpc_helper.go:80 FVM AppendFSL Close Error rpc error: code = Unknown desc = compiling failed: compiling FSL failed
safeline-mgt  | 2025/05/29 10:42:18 [ERROR] fvm fvm/policy_rule.go:66 compile and push fsl error: rpc error: code = Unknown desc = compiling failed: compiling FSL failed
safeline-mgt  | 2025/05/29 10:42:18 [ERROR] api.policy gin@v1.10.0/context.go:185 create policy error: rules compile error, please check your params

The 'safeline-fvm' container logs show the following errors:

safeline-fvm  | time="2025-05-29T10:42:18Z" level=error msg="AppendFSL: compiling failed: compiling FSL failed"

API response:

{
    "data": {},
    "msg": "internal-error"
}

Reproduce the POST to /api/open/policy with the supplied docker-compose.yml and inspect the safeline-mgt and safeline-fvm logs. Start with fvm/grpc_helper.go and fvm/policy_rule.go, then trace the FSL compilation failure. Done means the request creates the policy successfully and no longer returns internal-error or compiling failed.