facts: add FactProcessError to log, not explode, issues processing facts

Co-authored-by: Sven Augustin <[email protected]>

Author: NichtJens

src/pyinfra/api/__init__.py

@@ -14,6 +14,7 @@
     FactError,
     FactTypeError,
     FactValueError,
+    FactProcessError,
     InventoryError,
     OperationError,
     OperationTypeError,

src/pyinfra/api/exceptions.py

@@ -29,6 +29,12 @@ class FactValueError(FactError, ValueError):
     """
 
 
+class FactProcessError(FactError, RuntimeError):
+    """
+    Exception raised when the data gathered for a fact cannot be processed.
+    """
+
+
 class OperationError(PyinfraError):
     """
     Exception raised during fact gathering staging if an operation is unable to

src/pyinfra/api/facts.py

@@ -24,6 +24,7 @@
 from pyinfra import logger
 from pyinfra.api import StringCommand
 from pyinfra.api.arguments import all_global_arguments, pop_global_arguments
+from pyinfra.api.exceptions import FactProcessError
 from pyinfra.api.util import (
     get_kwargs_str,
     log_error_or_warning,
@@ -269,7 +270,22 @@ def _get_fact(
 
     if status:
         if stdout_lines:
-            data = fact.process(stdout_lines)
+            try:
+                data = fact.process(stdout_lines)
+            except FactProcessError as e:
+                log_error_or_warning(
+                    host,
+                    global_kwargs["_ignore_errors"],
+                    description=("could not process fact: {0} {1}").format(
+                        name, get_kwargs_str(fact_kwargs)
+                    ),
+                    exception=e,
+                )
+
+                # Check we've not failed
+                if apply_failed_hosts and not global_kwargs["_ignore_errors"]:
+                    state.fail_hosts({host})
+
     elif stderr_lines:
         # If we have error output and that error is sudo or su stating the user
         # does not exist, do not fail but instead return the default fact value.

src/pyinfra/api/util.py

@@ -222,7 +222,11 @@ def log_operation_start(
 
 
 def log_error_or_warning(
-    host: "Host", ignore_errors: bool, description: str = "", continue_on_error: bool = False
+    host: "Host",
+    ignore_errors: bool,
+    description: str = "",
+    continue_on_error: bool = False,
+    exception: Exception | None = None,
 ) -> None:
     log_func = logger.error
     log_color = "red"
@@ -237,6 +241,16 @@ def log_error_or_warning(
         if description:
             log_text = f"{log_text}: "
 
+    if exception:
+        exc = exception.__cause__ or exception
+        exc_text = "{0}: {1}".format(type(exc).__name__, exc)
+        log_func(
+            "{0}{1}".format(
+                host.print_prefix,
+                click.style(exc_text, log_color),
+            ),
+        )
+
     log_func(
         "{0}{1}{2}".format(
             host.print_prefix,