sync

plantdb.client.sync

Synchronization Utility for PlantDB Databases

This module provides a robust synchronization mechanism for File System Databases (FSDB) in the PlantDB project, enabling seamless data transfer between local and remote database instances.

Key Features

• Support for local and remote database synchronization
• Intelligent file transfer with modification time and size checking
• Automatic locking and unlocking of source and target databases
• Recursive directory synchronization
• SSH-based remote file transfer using SFTP
• HTTP(S) REST API synchronization with archive transfer
• Support for FSDB instances, local paths, and various remote protocols
• Error handling and validation of database paths

Usage Examples

Local Path to Local Path

Create two test databases, a source with a dataset and a target without dataset, then sync them.

>>> from plantdb.client.sync import FSDBSync
>>> from plantdb.commons.test_database import test_database
>>> # Create a test source database
>>> db_source = test_database()
>>> db_source.connect()
>>> print(db_source.list_scans())  # list scans in the source database
['real_plant_analyzed']
>>> db_source._unlock_db()  # Unlock the database (remove lock file)
>>> # Create a test target database
>>> db_target = test_database(dataset=None)
>>> db_target.connect()
>>> print(db_target.list_scans())  # verify that target database is empty
[]
>>> db_target._unlock_db()  # Unlock the database (remove lock file)
>>> # Sync target database with source
>>> db_sync = FSDBSync(db_source.path(), db_target.path())
>>> db_sync.sync()
>>> # List directories in the target database
>>> print([i for i in db_target.path().iterdir()])
>>> # Reload target database to ensure that the new scans are available
>>> db_target.reload()
>>> print(db_target.list_scans())  # verify that target database contains 1 new scan
['real_plant_analyzed']
>>> db_source.disconnect()  # Remove the test database
>>> db_target.disconnect()  # Remove the test database

FSDB instance to Local Path

>>> from plantdb.client.sync import FSDBSync
>>> from plantdb.commons.test_database import test_database
>>> # Create a test source database
>>> db_source = test_database()
>>> # Create a test target database
>>> db_target = test_database(dataset=None)
>>> # FSDB instance to local path
>>> db_sync = FSDBSync(db_source, db_target.path())
>>> db_sync.sync()
>>> # Connect to the target and list scans
>>> db_target.connect()
>>> print(db_target.list_scans())  # verify that target now has the 'real_plant_analyzed' dataset
['real_plant_analyzed']
>>> db_target.disconnect()
>>> db_source.disconnect()

Local path to HTTP REST API

>>> from plantdb.client.sync import FSDBSync
>>> from plantdb.server.test_rest_api import TestRestApiServer
>>> from plantdb.client.rest_api import list_scan_names
>>> from plantdb.commons.test_database import test_database
>>> # Create a test source database with all 5 test dataset
>>> db_source = test_database("all")
>>> # Create a test target database
>>> db_target = TestRestApiServer(test=True, empty=True)
>>> db_target.start()
Test REST API server started at http://127.0.0.1:5000
>>> server_cfg = db_target.get_server_config()
>>> # Use REST API to list scans and verify target DB is empty
>>> scans_list = list_scan_names(**server_cfg)
>>> print(scans_list)
[]
>>> # Asynchronous sync target database with source
>>> db_sync = FSDBSync(db_source.path(), db_target.get_base_url())
>>> thread = db_sync.sync(thread=True)  # Returns immediately
>>> print(f"Database synchronization in progress: {db_sync.is_synchronizing()}")
>>> # Monitor progress
>>> import time
>>> while db_sync.is_synchronizing():
...     progress = db_sync.get_sync_progress()
...     print(f"Progress: {progress:.1f}%")
...     time.sleep(0.3)
>>> # Wait for completion
>>> db_sync.wait_for_sync()
>>> # Check for errors
>>> if db_sync.get_sync_error():
...     print(f"Sync failed: {db_sync.get_sync_error()}")
>>> else:
...     print("Sync completed successfully")
>>> # Use REST API endpoint to refresh scans
>>> from plantdb.client.rest_api import refresh
>>> refresh(**server_cfg)
>>> # Use REST API to list scans and verify target DB contains the new scans
>>> scans_list = list_scan_names(**server_cfg)
>>> print(scans_list)
['arabidopsis000', 'real_plant', 'real_plant_analyzed', 'virtual_plant', 'virtual_plant_analyzed']
>>> db_target.stop()

SSH to local with credentials

>>> db_sync = FSDBSync("ssh://server.example.com:/data/sourcedb", "/local/target/db")
>>> db_sync.set_ssh_credentials("server.example.com", "username", "password")
>>> db_sync.sync()

FSDBSync

FSDBSync(source, target)

Class for sync between two FSDB databases with support for multiple protocols.

It supports synchronization between different types of database sources and targets: - FSDB instances or local paths: Uses file system operations - HTTP(S) URLs: Uses REST API with archive transfer - SSH URLs: Uses SFTP protocol

It checks for the validity of both source and target and locks the databases during sync.

Attributes:

Name	Type	Description
source_str	str or FSDB or Path	Source database specification
target_str	str or FSDB or Path	Target database specification
source	dict	Source database description
target	dict	Target database description
ssh_clients	dict	Dictionary of SSH clients, keyed by host name.
ssh_credentials	dict	Dictionary of SSH credentials, keyed by host name.
synchronizing	bool	Flag indicating whether a sync operation is currently in progress.
sync_progress	float	Progress of the sync operation as a percentage.

Examples:

>>> from plantdb.client.sync import FSDBSync
>>> from plantdb.commons.test_database import test_database
>>> # Example: Create two test databases, a source with a dataset and a target without dataset, then sync them.
>>> # Create a test source database
>>> db_source = test_database()
>>> db_source.connect()
>>> print(db_source.list_scans())  # list scans in the source database
['real_plant_analyzed']
>>> db_source._unlock_db()  # Unlock the database (remove lock file)
>>> # Create a test target database
>>> db_target = test_database(dataset=None)
>>> db_target.connect()
>>> print(db_target.list_scans())  # verify that target database is empty
[]
>>> db_target._unlock_db()  # Unlock the database (remove lock file)
>>> # Sync target database with source
>>> db_sync = FSDBSync(db_source.path(), db_target.path())
>>> db_sync.sync()
>>> # List directories in the target database
>>> print([i for i in db_target.path().iterdir()])
>>> # Reload target database to ensure that the new scans are available
>>> db_target.reload()
>>> print(db_target.list_scans())  # verify that target database contains 1 new scan
['real_plant_analyzed']
>>> db_source.disconnect()  # Remove the test database
>>> db_target.disconnect()  # Remove the test database

Class constructor.

Parameters:

Name	Type	Description	Default
source	str or Path or FSDB	Source database specification: - FSDB instance or local path for file system databases - HTTP(S) URL for REST API access - SSH URL (ssh://server.example.com:/path/to/db) for SFTP access	required
target	str or Path or FSDB	Target database specification (same format as source)	required

Source code in plantdb/client/sync.py

def __init__(self, source, target):
    """Class constructor.

    Parameters
    ----------
    source : str or pathlib.Path or FSDB
        Source database specification:
        - FSDB instance or local path for file system databases
        - HTTP(S) URL for REST API access
        - SSH URL (ssh://server.example.com:/path/to/db) for SFTP access
    target : str or pathlib.Path or FSDB
        Target database specification (same format as source)
    """
    self.source_str = source
    self.target_str = target
    self.source = _parse_database_spec(source)
    self.target = _parse_database_spec(target)
    self.ssh_clients = {}  # Store SSH connections
    self.ssh_credentials = {}  # Store SSH credentials
    self.sync_progress = 0.
    self._sync_thread = None
    self._sync_error = None

__del__

__del__()

Ensure unlocking on object destruction.

Source code in plantdb/client/sync.py

def __del__(self):
    """Ensure unlocking on object destruction."""
    try:
        self.unlock()
    except:
        return

get_sync_error

get_sync_error()

Get any error that occurred during threaded synchronization.

Returns:

Type	Description
Exception or None	The exception that occurred during sync, or None if no error.

Source code in plantdb/client/sync.py

def get_sync_error(self):
    """Get any error that occurred during threaded synchronization.

    Returns
    -------
    Exception or None
        The exception that occurred during sync, or `None` if no error.
    """
    return self._sync_error

get_sync_progress

get_sync_progress()

Get the current synchronization progress.

Returns:

Type	Description
float	Progress as a percentage (0.0 to 100.0).

Source code in plantdb/client/sync.py

def get_sync_progress(self):
    """Get the current synchronization progress.

    Returns
    -------
    float
        Progress as a percentage (0.0 to 100.0).
    """
    return self.sync_progress

is_synchronizing

is_synchronizing()

Check if synchronization is currently in progress.

Returns:

Type	Description
bool	True if synchronization is in progress, False otherwise.

Source code in plantdb/client/sync.py

def is_synchronizing(self):
    """Check if synchronization is currently in progress.

    Returns
    -------
    bool
        `True` if synchronization is in progress, `False` otherwise.
    """
    return self._sync_thread is not None

lock

lock()

Lock both source and target databases prior to sync.

Source code in plantdb/client/sync.py

def lock(self):
    """Lock both source and target databases prior to sync."""
    for db in [self.source, self.target]:
        if db["type"] == "ssh":
            self._lock_remote(db)

set_ssh_credentials

set_ssh_credentials(host, username, password=None)

Set SSH credentials for a specific host.

Parameters:

Name	Type	Description	Default
host	str	The hostname for SSH connection	required
username	str	SSH username	required
password	str	SSH password. If not provided, will be prompted during connection.	None

Source code in plantdb/client/sync.py

def set_ssh_credentials(self, host, username, password=None):
    """Set SSH credentials for a specific host.

    Parameters
    ----------
    host : str
        The hostname for SSH connection
    username : str
        SSH username
    password : str, optional
        SSH password. If not provided, will be prompted during connection.
    """
    self.ssh_credentials[host] = {
        'username': username,
        'password': password
    }

sync

sync(source_scans=None, thread=False)

Sync the two DBs using the appropriate strategy based on database types.

Parameters:

Name	Type	Description	Default
source_scans	list of str	List of scan IDs to synchronize. If None, synchronizes all scans.	None
thread	bool	If True, run synchronization in a separate thread. Default is False. When running in a thread, use is_synchronizing() to check status and get_sync_progress() to track progress.	False

Returns:

Type	Description
Thread or None	If thread=True, returns the Thread object. Otherwise, returns None.

Source code in plantdb/client/sync.py

def sync(self, source_scans=None, thread=False):
    """Sync the two DBs using the appropriate strategy based on database types.

    Parameters
    ----------
    source_scans : list of str, optional
        List of scan IDs to synchronize. If `None`, synchronizes all scans.
    thread : bool, optional
        If `True`, run synchronization in a separate thread. Default is `False`.
        When running in a thread, use `is_synchronizing()` to check status
        and `get_sync_progress()` to track progress.

    Returns
    -------
    threading.Thread or None
        If `thread=True`, returns the `Thread` object. Otherwise, returns `None`.
    """
    if thread:
        if self.is_synchronizing():
            raise RuntimeError("Synchronization is already in progress")

        self._sync_thread = threading.Thread(target=self._sync_worker, args=(source_scans,))
        self._sync_thread.daemon = True
        self._sync_thread.start()
        return self._sync_thread
    else:
        self._sync_worker(source_scans)

unlock

unlock()

Unlock both source and target databases after sync.

Source code in plantdb/client/sync.py

def unlock(self):
    """Unlock both source and target databases after sync."""
    for db in [self.source, self.target]:
        if db["type"] == "ssh":
            self._unlock_remote(db)

wait_for_sync

wait_for_sync(timeout=None)

Wait for the synchronization thread to complete.

Parameters:

Name	Type	Description	Default
timeout	float	Maximum time to wait in seconds. If None, wait indefinitely.	None

Returns:

Type	Description
bool	True if the thread is completed, False if timeout was reached.

Source code in plantdb/client/sync.py

def wait_for_sync(self, timeout=None):
    """Wait for the synchronization thread to complete.

    Parameters
    ----------
    timeout : float, optional
        Maximum time to wait in seconds. If `None`, wait indefinitely.

    Returns
    -------
    bool
        `True` if the thread is completed, `False` if timeout was reached.
    """
    if self._sync_thread is not None:
        self._sync_thread.join(timeout)
        return not self._sync_thread.is_alive()
    return True

config_from_url

config_from_url(url)

Parse URL into a configuration dictionary.

Examples:

>>> from plantdb.client.sync import config_from_url
>>> config = config_from_url("http://localhost:5014/api/")
>>> print(config)
{'protocol': 'http', 'host': 'localhost', 'port': 5014, 'prefix': '/api/', 'ssl': False}

Source code in plantdb/client/sync.py

def config_from_url(url):
    """Parse URL into a configuration dictionary.

    Examples
    --------
    >>> from plantdb.client.sync import config_from_url
    >>> config = config_from_url("http://localhost:5014/api/")
    >>> print(config)
    {'protocol': 'http', 'host': 'localhost', 'port': 5014, 'prefix': '/api/', 'ssl': False}
    """
    parsed_url = urllib3.util.parse_url(url)
    config = {}
    config["protocol"] = parsed_url.scheme.lower()
    config["host"] = parsed_url.host
    config["port"] = parsed_url.port
    config["prefix"] = parsed_url.path
    config["ssl"] = True if "https" in url else False
    return config