Files
defrag/app/migration/copy.py
2025-12-13 11:56:06 +01:00

269 lines
7.6 KiB
Python

"""Copy-based migration strategy"""
import shutil
from pathlib import Path
from typing import Optional
import os
from ..shared.logger import ProgressLogger
class CopyMigrationStrategy:
"""Copy files to destination with verification"""
def __init__(
self,
logger: Optional[ProgressLogger] = None,
preserve_metadata: bool = True,
verify_checksums: bool = True
):
"""Initialize copy migration strategy
Args:
logger: Optional progress logger
preserve_metadata: Whether to preserve file metadata
verify_checksums: Whether to verify checksums after copy
"""
self.logger = logger
self.preserve_metadata = preserve_metadata
self.verify_checksums = verify_checksums
def migrate(
self,
source: Path,
destination: Path,
verify: bool = True
) -> bool:
"""Migrate file by copying
Args:
source: Source file path
destination: Destination file path
verify: Whether to verify the operation
Returns:
True if migration successful
"""
if not source.exists():
if self.logger:
self.logger.error(f"Source file does not exist: {source}")
return False
# Create destination directory
destination.parent.mkdir(parents=True, exist_ok=True)
try:
# Copy file
if self.preserve_metadata:
shutil.copy2(source, destination)
else:
shutil.copy(source, destination)
# Verify if requested
if verify and self.verify_checksums:
if not self._verify_copy(source, destination):
if self.logger:
self.logger.error(f"Verification failed: {source} -> {destination}")
destination.unlink()
return False
return True
except Exception as e:
if self.logger:
self.logger.error(f"Copy failed: {source} -> {destination}: {e}")
return False
def _verify_copy(self, source: Path, destination: Path) -> bool:
"""Verify copied file
Args:
source: Source file path
destination: Destination file path
Returns:
True if verification successful
"""
# Check size
source_size = source.stat().st_size
dest_size = destination.stat().st_size
if source_size != dest_size:
return False
# Compare checksums for files larger than 1MB
if source_size > 1024 * 1024:
from ..deduplication.chunker import hash_file
source_hash = hash_file(source)
dest_hash = hash_file(destination)
return source_hash == dest_hash
# For small files, compare content directly
with open(source, 'rb') as f1, open(destination, 'rb') as f2:
return f1.read() == f2.read()
def can_migrate(self, source: Path, destination: Path) -> bool:
"""Check if migration is possible
Args:
source: Source file path
destination: Destination file path
Returns:
True if migration is possible
"""
if not source.exists():
return False
# Check if destination directory is writable
dest_dir = destination.parent
if dest_dir.exists():
return os.access(dest_dir, os.W_OK)
# Check if parent directory exists and is writable
parent = dest_dir.parent
while not parent.exists() and parent != parent.parent:
parent = parent.parent
return parent.exists() and os.access(parent, os.W_OK)
def estimate_time(self, source: Path) -> float:
"""Estimate migration time in seconds
Args:
source: Source file path
Returns:
Estimated time in seconds
"""
if not source.exists():
return 0.0
size = source.stat().st_size
# Estimate based on typical copy speed (100 MB/s)
typical_speed = 100 * 1024 * 1024 # bytes per second
return size / typical_speed
def cleanup(self, source: Path) -> bool:
"""Cleanup source file after successful migration
Args:
source: Source file path
Returns:
True if cleanup successful
"""
try:
if source.exists():
source.unlink()
return True
except Exception as e:
if self.logger:
self.logger.warning(f"Failed to cleanup {source}: {e}")
return False
class FastCopyStrategy(CopyMigrationStrategy):
"""Fast copy strategy without verification"""
def __init__(self, logger: Optional[ProgressLogger] = None):
"""Initialize fast copy strategy"""
super().__init__(
logger=logger,
preserve_metadata=True,
verify_checksums=False
)
class SafeCopyStrategy(CopyMigrationStrategy):
"""Safe copy strategy with full verification"""
def __init__(self, logger: Optional[ProgressLogger] = None):
"""Initialize safe copy strategy"""
super().__init__(
logger=logger,
preserve_metadata=True,
verify_checksums=True
)
class ReferenceCopyStrategy:
"""Create reference copy using reflinks (CoW) if supported"""
def __init__(self, logger: Optional[ProgressLogger] = None):
"""Initialize reflink copy strategy"""
self.logger = logger
def migrate(
self,
source: Path,
destination: Path,
verify: bool = True
) -> bool:
"""Migrate using reflink (copy-on-write)
Args:
source: Source file path
destination: Destination file path
verify: Whether to verify the operation
Returns:
True if migration successful
"""
if not source.exists():
if self.logger:
self.logger.error(f"Source file does not exist: {source}")
return False
# Create destination directory
destination.parent.mkdir(parents=True, exist_ok=True)
try:
# Try reflink copy (works on btrfs, xfs, etc.)
import subprocess
result = subprocess.run(
['cp', '--reflink=auto', str(source), str(destination)],
capture_output=True,
check=False
)
if result.returncode != 0:
# Fallback to regular copy
shutil.copy2(source, destination)
return True
except Exception as e:
if self.logger:
self.logger.error(f"Reflink copy failed: {source} -> {destination}: {e}")
return False
def can_migrate(self, source: Path, destination: Path) -> bool:
"""Check if migration is possible"""
if not source.exists():
return False
dest_dir = destination.parent
if dest_dir.exists():
return os.access(dest_dir, os.W_OK)
return True
def estimate_time(self, source: Path) -> float:
"""Estimate migration time (reflinks are fast)"""
return 0.1 # Reflinks are nearly instant
def cleanup(self, source: Path) -> bool:
"""Cleanup source file"""
try:
if source.exists():
source.unlink()
return True
except Exception as e:
if self.logger:
self.logger.warning(f"Failed to cleanup {source}: {e}")
return False