Default Behavior


This document describes the assumptions that Guild makes in the absence of explicit configuration.

In general, Guild must know the following about an operation:

If this information is not defined explicitly in a Guild file, Guild attempts to infer the information using rules based on what you run.

Python Scripts

Unless otherwise configured in a Guild file, Guild makes assumptions when running Python scripts. This includes cases when a script is run directly and when a script is defined using the main operation attribute.

Flags Interface

If flags-dest is not defined for an operation, Guild attempts to detect the interface by inspecting the Python module.

  • If the module imports the argparse, Guild assumes that flags are set using command line arguments and uses args for flags-dest.

  • If the main module does not import argparse, Guild assumes that flags are defined in global variables and uses globals for flags-dest.

If you set flags-dest for an operation, Guild inspects the Python main module to infer the flags interface.

Example: Command Line Arguments

Consider the following Python module train:

import argparse

p = argparse.ArgumentParser()
p.add_argument("--learning-rate", type=float, default=0.1)
p.add_argument("--batch-size", type=int, default=100)

args = p.parse_args()

# Use args to train model, etc.

Unless flags-dest is configured for the operation, Guild inspects the module and detects the import of argparse and uses args.

Example: Global Variables

The following version of train does not import argparse. It defines flags as global variables.

learning_rate = 0.1
batch_size = 100

# Use globals to train model, etc.

Unless otherwise configured, when Guild inspects this module, it uses
globals as the value for flags-dest.

  flags-dest: globals

Flag Imports

Once Guild determines the flags interface for a Python module (see above), it tries to import flag definitions. The import method depends on the interface.

While you cannot control how Guild imports flags, you can control what flags are imported, if any.

By default, Guild imports all detected flags.

For details on controlling flag imports, see Import Flags.

Output Scalars

By default, Guild looks for scalar values in script output. It does this regardless of the language type.

Guild detects patterns in the format: KEY: VALUE, where KEY is a scalar identifier that occurs at the start of a line and VALUE is a valid float represenation. Guild logs these key/value pairs as scalars.

You can test Guild’s current output scalar configruation by running the operation with the --test-output-scalars option.

If your script prints scalar values in a different format, you can control the pattern that Guild uses by defining the output-scalars attribute for an operation.

Refer to Output Scalar for more information.