examples.md

Examples

Audience: MXC consumers

For a more comprehensive list of examples, see tests/examples/.

Basic Hello World

{
  "version": "1.0.0",
  "containment": "processcontainer",
  "process": {
    "commandLine": "python -c \"import sys; print('Hello from MXC!'); print(sys.version)\""
  }
}

Filesystem Access Control

{
  "version": "1.0.0",
  "containment": "processcontainer",
  "process": {
    "commandLine": "python -c \"open('C:\\\\temp\\\\output.txt', 'w').write('test')\""
  },
  "filesystem": {
    "readwritePaths": [
      "C:\\temp"
    ],
    "deniedPaths": [
      "C:\\Windows\\System32"
    ]
  }
}

Create C:\temp before running this example, or replace it with an existing writable directory.

Network Restricted Execution

{
  "version": "1.0.0",
  "containment": "processcontainer",
  "process": {
    "commandLine": "python -c \"import socket; socket.create_connection(('140.82.114.6', 443), timeout=5).close(); print('Allowed destination reached')\"",
    "timeout": 30000
  },
  "processContainer": {
    "capabilities": ["internetClient"]
  },
  "network": {
    "egress": {
      "default": "deny",
      "allow": [{
        "to": [{ "cidr": "140.82.114.6/32" }],
        "ports": [{ "protocol": "tcp", "port": 443 }]
      }]
    },
    "ingress": { "default": "deny", "hostLoopback": "deny" }
  }
}

The destination is numeric because directional rules accept IP/CIDR, not hostnames. It must be reachable from the host to demonstrate the allow rule; see the ProcessContainer networking guide for host requirements and enforcement limits.

Directional Network Policy (schema 0.9+)

Supported contracts use explicit egress CIDR, protocol, and port rules plus separate ingress defaults:

{
  "version": "0.9.0-alpha",
  "containment": "processcontainer",
  "process": {
    "commandLine": "cmd.exe /c echo directional network example"
  },
  "network": {
    "egress": {
      "default": "deny",
      "allow": [
        {
          "to": [{ "cidr": "192.0.2.0/24" }],
          "ports": [{ "protocol": "tcp", "port": 443 }]
        }
      ]
    },
    "ingress": {
      "default": "deny",
      "hostLoopback": "deny"
    }
  }
}

See tests/examples/30_network_0_8_directional.json for the complete config and the supported schema guide for current backend authoring.

Network Proxy

Supported contracts name a running localhost proxy using runtimeConfig.networkProxy. Egress must default to deny, with no direct allow or deny rules. For an unpackaged host proxy on ProcessContainer, the development/testing configuration is:

{
  "version": "1.0.0",
  "containment": "processcontainer",
  "process": {
    "commandLine": "python -c \"import urllib.request; print(urllib.request.urlopen('https://api.github.com').status)\"",
    "timeout": 30000
  },
  "processContainer": {
    "capabilities": ["internetClient"]
  },
  "network": {
    "egress": { "default": "deny" },
    "ingress": { "default": "allow", "hostLoopback": "allow" }
  },
  "runtimeConfig": {
    "networkProxy": "http://127.0.0.1:8080"
  }
}

This identity-less host-loopback deployment restricts client egress to the configured proxy address and port, but does not verify which process owns that endpoint. It supports PSEC 1.0-only hosts and hosts with PSEC 1.1 or newer that advertise ingress support. PSEC 1.1 or newer without that flag rejects the request, even if the host also accepts PSEC 1.0 payloads. For production ProcessContainer deployments, identify a packaged proxy through processContainer.network.allowedProxyPeer instead; see proxy deployment choices. Bubblewrap and Seatbelt also support a caller-managed loopback proxy, but their supported ingress policies differ. See their backend guides.

egress / ingress / runtimeConfig.networkProxy

Every supported contract (0.9.0-alpha or later) accepts the directional shape and rejects the retired defaultPolicy, host-list, and network.proxy fields. This is the cross-backend schema, not a backend-specific format: it's parsed the same way regardless of containment. Each backend independently declares which parts of it — if any — it actually enforces; a backend that hasn't declared support for a given field rejects a config that sets it.

Note that EGRESS_RULES is what carries per-CIDR/port rules; a backend without it accepts only egress.default. On Seatbelt, runtimeConfig.networkProxy covers only loopback endpoints; there is no supported equivalent for a remote proxy URL or builtinTestServer. See tests/examples/31_mac_network_0_8.json for a complete example:

{
  "version": "0.9.0-alpha",
  "containment": "seatbelt",
  "network": {
    "egress": { "default": "deny" },
    "ingress": { "default": "deny", "hostLoopback": "deny" }
  },
  "runtimeConfig": {
    "networkProxy": "http://127.0.0.1:8080"
  }
}