functions-in-python.md

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Write Functions in Python

The Teaclave platform provides a convenient way to register a customized function written in Python, and the function is interpreted at runtime in an isolated trusted execution environment (i.e., Intel SGX).

Entrypoint

Here is an simple example of an echo function:

def entrypoint(argv):
    assert argv[0] == 'message'
    assert argv[1] is not None
    return argv[1]

The entrypoint function defined above is the "entrypoint" to executing the function. It takes one argument which is a list of arguments of this echo function. The return value of the entrypoint function will be passed back to the client.

::: tip NOTE Note that the function arguments in key-value format passed from the platform are flattened into a list. For example, the {"message": "Hello, Teaclave!"} arguments will become "message" (argv[0]) and "Hello, Teaclave!" (argv[1]). :::

Modules

Current Python executor (i.e., MesaPy) already supports many modules of the original Python standard library such as marshal, math, binascii, itertools, micronumpy. You can find a full list of available modules in the document of MesaPy for SGX.

Besides these modules for general computation, you may curious about doing file I/O in customized Python function. We provides APIs to integrated with the executor runtime to read/write files registered along with the task. You can either open a file through the teaclave_open function or with the teaclave module like this:

# open input via built-in teaclave_open
with teaclave_open("input_file", "rb") as f:
    line = f.readline()

# open input via teaclave module
from teaclave import open
with open("output_file", "wb") as f:
    f.write("This message is from Mesapy!")

Either function will give an file object in Python, you can use it to read lines or write data. And the first argument is the key of the registered input/output files.

You can learn more about advanced usages in the example of logistic regression in Python.