Lukas
afc1e44e99
- Add custom exception classes for structured error handling - Implement global exception handlers in FastAPI application - Add comprehensive request/response validation - Create exception contract tests for validation - Update backend development documentation Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
262 lines
8.0 KiB
Python
262 lines
8.0 KiB
Python
"""Shared domain exception classes used across routers and services.
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Exception Taxonomy
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==================
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All domain exceptions inherit from one of these base categories:
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- **NotFoundError** (404): Domain entity not found
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- **BadRequestError** (400): Invalid input, validation failure, invalid identifiers
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- **ConflictError** (409): State conflict, resource already exists, invalid state transition
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- **OperationError** (500): Operation failure, write errors
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- **ServiceUnavailableError** (503): Infrastructure/external service issues
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Service exceptions inherit from the appropriate category, allowing routers to
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handle categories rather than individual exception types. Exception handlers in
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main.py register only base category types.
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Example:
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def get_jail(name: str) -> Jail:
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# Raises JailNotFoundError (subclass of NotFoundError)
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...
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@app.exception_handler(NotFoundError)
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async def handle_not_found(request, exc):
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return JSONResponse(status_code=404, content={"detail": str(exc)})
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See Backend-Development.md for the complete exception contract.
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"""
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from __future__ import annotations
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# ---------------------------------------------------------------------------
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# Exception Base Classes (Categories)
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# ---------------------------------------------------------------------------
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class DomainError(Exception):
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"""Base class for all domain exceptions."""
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pass
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class NotFoundError(DomainError):
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"""Raised when a requested domain entity is not found. HTTP 404."""
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pass
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class BadRequestError(DomainError):
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"""Raised for invalid input, validation failures, or invalid identifiers. HTTP 400."""
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pass
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class ConflictError(DomainError):
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"""Raised for state conflicts or resource constraints. HTTP 409."""
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pass
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class OperationError(DomainError):
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"""Raised when a domain operation fails (write, update, etc.). HTTP 500."""
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pass
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class ServiceUnavailableError(DomainError):
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"""Raised for infrastructure or external service issues. HTTP 503."""
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pass
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# ---------------------------------------------------------------------------
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# Jail-Specific Exceptions
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# ---------------------------------------------------------------------------
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class JailNotFoundError(NotFoundError):
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"""Raised when a requested jail name does not exist."""
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def __init__(self, name: str) -> None:
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self.name = name
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super().__init__(f"Jail not found: {name!r}")
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class JailOperationError(ConflictError):
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"""Raised when a jail state operation fails (e.g. start/stop already in progress)."""
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class ConfigValidationError(BadRequestError):
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"""Raised when config values fail validation before applying."""
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class ConfigOperationError(BadRequestError):
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"""Raised when a config payload update or command fails."""
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class ConfigDirError(ServiceUnavailableError):
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"""Raised when the fail2ban config directory is missing or inaccessible."""
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class ConfigFileNotFoundError(NotFoundError):
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"""Raised when a requested config file does not exist."""
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def __init__(self, filename: str) -> None:
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"""Initialize with the filename that was not found.
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Args:
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filename: The filename that could not be located.
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"""
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self.filename = filename
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super().__init__(f"Config file not found: {filename!r}")
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class ConfigFileExistsError(ConflictError):
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"""Raised when trying to create a file that already exists."""
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def __init__(self, filename: str) -> None:
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"""Initialize with the filename that already exists.
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Args:
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filename: The filename that conflicts.
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"""
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self.filename = filename
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super().__init__(f"Config file already exists: {filename!r}")
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class ConfigFileWriteError(OperationError):
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"""Raised when a file cannot be written (permissions, disk full, etc.)."""
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class ConfigFileNameError(BadRequestError):
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"""Raised when a supplied filename is invalid or unsafe."""
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class ServerOperationError(BadRequestError):
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"""Raised when a server control command (e.g. refresh) fails."""
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class Fail2BanConnectionError(ServiceUnavailableError):
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"""Raised when the fail2ban socket is unreachable or returns an error."""
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def __init__(self, message: str, socket_path: str) -> None:
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"""Initialize with a human-readable message and the socket path.
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Args:
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message: Description of the connection problem.
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socket_path: The fail2ban socket path that was targeted.
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"""
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self.socket_path: str = socket_path
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super().__init__(f"{message} (socket: {socket_path})")
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class Fail2BanProtocolError(ServiceUnavailableError):
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"""Raised when the response from fail2ban cannot be parsed."""
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class FilterInvalidRegexError(BadRequestError):
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"""Raised when a regex pattern fails to compile."""
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def __init__(self, pattern: str, error: str) -> None:
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"""Initialize with the invalid pattern and compile error."""
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self.pattern = pattern
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self.error = error
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super().__init__(f"Invalid regex {pattern!r}: {error}")
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class JailNotFoundInConfigError(NotFoundError):
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"""Raised when the requested jail name is not defined in any config file."""
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def __init__(self, name: str) -> None:
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self.name = name
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super().__init__(f"Jail not found in config: {name!r}")
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class ConfigWriteError(OperationError):
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"""Raised when writing a configuration file modification fails."""
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def __init__(self, message: str) -> None:
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self.message = message
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super().__init__(message)
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class JailNameError(BadRequestError):
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"""Raised when a jail name contains invalid characters."""
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class JailAlreadyActiveError(ConflictError):
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"""Raised when trying to activate a jail that is already active."""
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def __init__(self, name: str) -> None:
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self.name = name
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super().__init__(f"Jail is already active: {name!r}")
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class JailAlreadyInactiveError(ConflictError):
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"""Raised when trying to deactivate a jail that is already inactive."""
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def __init__(self, name: str) -> None:
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self.name = name
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super().__init__(f"Jail is already inactive: {name!r}")
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class FilterNotFoundError(NotFoundError):
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"""Raised when the requested filter name is not found."""
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def __init__(self, name: str) -> None:
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self.name = name
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super().__init__(f"Filter not found: {name!r}")
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class FilterAlreadyExistsError(ConflictError):
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"""Raised when trying to create a filter whose `.conf` or `.local` already exists."""
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def __init__(self, name: str) -> None:
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self.name = name
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super().__init__(f"Filter already exists: {name!r}")
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class FilterNameError(BadRequestError):
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"""Raised when a filter name contains invalid characters."""
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class FilterReadonlyError(ConflictError):
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"""Raised when trying to delete a shipped `.conf` filter with no `.local` override."""
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def __init__(self, name: str) -> None:
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self.name = name
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super().__init__(
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f"Filter {name!r} is a shipped default (.conf only); only user-created .local files can be deleted."
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)
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class ActionNotFoundError(NotFoundError):
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"""Raised when the requested action name is not found."""
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def __init__(self, name: str) -> None:
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self.name = name
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super().__init__(f"Action not found: {name!r}")
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class ActionAlreadyExistsError(ConflictError):
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"""Raised when trying to create an action whose `.conf` or `.local` already exists."""
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def __init__(self, name: str) -> None:
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self.name = name
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super().__init__(f"Action already exists: {name!r}")
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class ActionNameError(BadRequestError):
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"""Raised when an action name contains invalid characters."""
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class ActionReadonlyError(ConflictError):
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"""Raised when trying to delete a shipped `.conf` action with no `.local` override."""
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def __init__(self, name: str) -> None:
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self.name = name
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super().__init__(
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f"Action {name!r} is a shipped default (.conf only); only user-created .local files can be deleted."
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)
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