77 lines
2.5 KiB
ReStructuredText
77 lines
2.5 KiB
ReStructuredText
.. only:: comment
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© Crown-owned copyright 2023, Defence Science and Technology Laboratory UK
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Database Client Server
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======================
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Database Service
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----------------
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The ``DatabaseService`` provides a SQL database server simulation by extending the base Service class.
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Key capabilities
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^^^^^^^^^^^^^^^^
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- Initialises a SQLite database file in the ``Node``'s ``FileSystem`` upon creation.
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- Handles connecting clients by maintaining a dictionary of connections mapped to session IDs.
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- Authenticates connections using a configurable password.
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- Executes SQL queries against the SQLite database.
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- Returns query results and status codes back to clients.
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- Leverages the Service base class for install/uninstall, status tracking, etc.
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Usage
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^^^^^
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- Install on a Node via the ``SoftwareManager`` to start the database service.
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- Clients connect, execute queries, and disconnect.
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- Service runs on TCP port 5432 by default.
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Implementation
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^^^^^^^^^^^^^^
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- Uses SQLite for persistent storage.
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- Creates the database file within the node's file system.
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- Manages client connections in a dictionary by session ID.
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- Processes SQL queries via the SQLite cursor and connection.
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- Returns results and status codes in a standard dictionary format.
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- Extends Service class for integration with ``SoftwareManager``.
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Database Client
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---------------
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The DatabaseClient provides a client interface for connecting to the ``DatabaseService``.
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Key features
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^^^^^^^^^^^^
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- Connects to the ``DatabaseService`` via the ``SoftwareManager``.
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- Executes SQL queries and retrieves result sets.
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- Handles connecting, querying, and disconnecting.
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- Provides a simple ``query`` method for running SQL.
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Usage
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^^^^^
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- Initialise with server IP address and optional password.
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- Connect to the ``DatabaseService`` with ``connect``.
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- Execute SQL queries via ``query``.
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- Retrieve results in a dictionary.
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- Disconnect when finished.
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To create database backups:
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- Configure the backup server on the ``DatabaseService`` by providing the Backup server ``IPv4Address`` with ``configure_backup``
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- Create a backup using ``backup_database``. This fails if the backup server is not configured.
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- Restore a backup using ``restore_backup``. By default, this uses the database created via ``backup_database``.
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Implementation
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^^^^^^^^^^^^^^
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- Leverages ``SoftwareManager`` for sending payloads over the network.
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- Connect and disconnect methods manage sessions.
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- Provides easy interface for applications to query database.
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- Payloads serialised as dictionaries for transmission.
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- Extends base Application class.
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