咨询OpenMDAO 2忽略外部代码轻微报错继续运行的方法

Got it, let's break down how to fix this issue— I’ve dealt with similar quirks when calling external code from OpenMDAO on Windows before, so I know exactly where to look. The key thing to note here: OpenMDAO usually terminates not just because of stderr output, but because your external code is returning a non-zero exit code (even for minor warnings). The fail_hard=False setting might not be working because it’s either misconfigured, or the root cause is the exit code check itself.

Here are targeted solutions, ordered by ease of implementation:

1. Verify Correct fail_hard Configuration #

First, make sure you’re passing fail_hard=False directly to the ExternalCodeComp constructor— it’s a component-level setting, not a global or command-line parameter. Example of the correct setup:

from openmdao.api import ExternalCodeComp

external_comp = ExternalCodeComp(
    fail_hard=False,
    command=["your_external_program.exe", "--input", "data.txt"],
    # Add your inputs, outputs, and other parameters here
)

If you were setting this elsewhere (like in a run script’s arguments), it won’t affect the component’s error handling.

2. Force Override the External Code’s Exit Code #

If your external program returns a non-zero exit code but produces valid results, you can manually reset the exit code that OpenMDAO checks. Create a custom component that inherits from ExternalCodeComp and overrides the return code after execution:

from openmdao.api import ExternalCodeComp

class LenientExternalCode(ExternalCodeComp):
    def compute(self, inputs, outputs):
        # Run the external code as usual
        super().compute(inputs, outputs)
        # Force OpenMDAO to treat the run as successful
        self.return_code = 0

Use this custom component instead of the default ExternalCodeComp in your model.

3. Redirect stderr to Null (Windows-Specific) #

While this won’t fix exit code issues, it will prevent OpenMDAO from capturing harmless warning outputs, which can reduce confusion. Modify your command to redirect stderr to Windows’ null device (nul):

command = ["your_external_program.exe", "--input", "data.txt", "2>", "nul"]

The 2> syntax tells the Windows shell to send stderr (stream 2) to the null device, discarding the output entirely.

4. Customize Error Check Logic #

For full control, override the default error-checking method in ExternalCodeComp to skip or customize failure conditions. This lets you ignore non-zero exit codes or only flag specific critical errors in stderr:

from openmdao.api import ExternalCodeComp

class CustomErrorCheckExternalCode(ExternalCodeComp):
    def check_run_status(self, retval, stderr, stdout):
        # Skip the default exit code check entirely
        # Optional: Add custom logic here, e.g., only fail if stderr contains "FATAL ERROR"
        if "FATAL ERROR" in stderr:
            raise RuntimeError("Critical error in external code")
        # Otherwise, do nothing and proceed

This method runs after the external code executes, so you can define exactly what counts as a "failure" for your use case.

Quick Debug Tip #

Before diving into code fixes, manually run your external program in Windows Shell and check its exit code with echo %errorlevel%. If the exit code is 0 but OpenMDAO still terminates, the issue might be specific content in stderr— use the stderr_file parameter to write stderr to a file, then adjust your custom error check to ignore those harmless lines.

内容的提问来源于stack exchange，提问作者Laurynas Mačiulis