liberty-plugins

Plugins for Liberty Framework

✅ Dags

Daily DAGs

• airflow-purge-daily-1: Purges old Airflow logs and metadata on a daily schedule (@daily).
• database-backup-daily-1: Backs up databases every day at 01:00 AM (00 1 * * *).

Weekly DAGs

• database-purge-weekly-1: Performs database cleanup and purging on a weekly schedule (@weekly).

Unscheduled DAGs

• airflow-sync-1: Synchronizes repositories as needed (manually triggered).

✅ Airflow Purge

Overview

This function automates the purge of Airflow dags, jobs and logs.

Purge Functions

• dag_runs: Deletes old DAG run records from the Airflow database based on the retention period set in the airflow_retention_days variable.
• task_instances: Removes outdated task instance records from the database, ensuring only recent executions are retained.
• jobs: Cleans up old job entries by deleting records where the job's end date is beyond the retention threshold.
• logs_in_db: Deletes historical log entries stored in the Airflow database to free up space and improve query performance.
• logs_on_disk: Scans and removes log files from the Airflow logs directory that exceed the configured retention period, keeping disk usage in check.

Configuration

• The retention period is controlled by the Airflow Variable: airflow_retention_days.
• If the variable is not set, the default retention period is 30 days.
• Logs stored in the database and on disk are purged accordingly.

Usage

• These functions should be executed periodically to prevent excessive log and metadata buildup.
• They can be added to an Airflow DAG that runs on a daily schedule (@daily).

✅ Airflow PostgreSQL Backup

Overview

This function automates the backup of PostgreSQL databases using pg_dump, managed as an Airflow task.

Function

• pg_dump(dag, database_name, conn_id="postgres_conn"): Creates a BashOperator task to back up a PostgreSQL database.
  • dag: The DAG to which this task belongs.
  • database_name: The name of the database to be backed up.
  • conn_id: The Airflow connection ID for PostgreSQL (default: postgres_conn).
  • Returns: A BashOperator task that executes the backup.

Configuration

• The connection details are fetched dynamically from Airflow using get_connection.
• The backup location is inside $AIRFLOW_HOME/tmp/.
• Environment variables are used to avoid storing credentials in plaintext.

Usage

• This function should be used within an Airflow DAG.
• It ensures database backups are automated and stored securely.
• Can be scheduled to run at desired intervals using DAG scheduling.

✅ Database Utils

Overview

This module provides utility functions for retrieving database connection details and column metadata for Oracle and PostgreSQL.

Functions

• get_column_lengths(spark, table, schema, conn_source): Retrieves column lengths based on the database type.
• get_column_types(data_df, column_lengths, conn_source): Generates a SQL column type definition string for Oracle or PostgreSQL.
• get_connection(conn_id, schema=None): Dynamically retrieves database connection details from Airflow based on the connection type.

Configuration

• Supports both Oracle (oracle.jdbc.driver.OracleDriver) and PostgreSQL (org.postgresql.Driver).
• Uses Airflow's BaseHook to dynamically retrieve connection details.
• Calls appropriate helper functions based on the detected database type.

Usage

• Can be integrated into Airflow DAGs for database connection handling.
• Useful for schema extraction, table metadata analysis, and type mapping.
• Ensures compatibility with both Oracle and PostgreSQL environments.

✅ Postgres Utils

Overview

This module provides utility functions for working with Apache Spark and PostgreSQL within an Airflow environment.

Functions

• create_spark_session(): Initializes and returns a Spark session with predefined configurations.
• get_all_tables(spark, conn): Retrieves all tables from the database, categorizing them based on foreign key dependencies.
• get_foreign_key_dependencies(spark, conn): Fetches foreign key relationships between tables.
• topological_sort(dependencies): Performs a topological sort on a given dependency graph.
• get_primary_key_for_table(spark, table_name, conn): Retrieves the primary key columns for a specified table.
• delete_existing_rows(target_conn, primary_keys, table, rows_to_update): Deletes rows from the target database that need to be updated.
• merge_all_tables(conn_source, conn_target, source_schema, target_schema): Manages table synchronization by processing tables without foreign keys first and then handling dependent tables.
• merge_single_table(spark, table, source_conn, target_conn): Handles the data merging process for a single table, identifying rows to insert or update in the target database.

Configuration

• Spark session is configured with JDBC drivers for PostgreSQL and Oracle.
• PostgreSQL connections are retrieved dynamically using get_connection.
• Foreign key dependencies are processed using topological sorting.

Usage

• Used for efficient data synchronization and migration between databases.
• Can be integrated into Airflow DAGs for automated execution.
• Supports large datasets by leveraging Spark’s distributed processing capabilities.

✅ Data Transfer Utils

Overview

This module provides utility functions for reading, processing, and writing data between databases using Apache Spark.

Functions

• read_data_from_db(spark, table, source_conn, source_schema): Reads data from a source database using JDBC.
• lowercase_columns(df): Converts all column names in a DataFrame to lowercase.
• write_data_to_db(spark, data_df, table, source_conn, source_schema, target_conn, target_schema): Writes data to a target database, ensuring proper column types and formatting.
• create_spark_session(): Initializes a Spark session with necessary configurations.
• copy_table(conn_source, conn_target, table_name, source_schema, target_schema): Copies a table from a source schema to a target schema, handling data transformation and loading.

Configuration

• Uses JDBC for database interactions.
• Handles column data type conversion to ensure compatibility.
• Utilizes get_column_lengths, get_column_types, and get_connection for metadata extraction and connection handling.

Usage

• Facilitates ETL operations between databases.
• Ensures clean and structured data processing.
• Can be integrated into Airflow DAGs for automated data migration workflows.

✅ Git Backup Utils

Overview

This module provides utility functions for managing backups in Git, including pulling, pushing, and purging old backups.

Functions

• pull_repository(local_path, repo_name, conn_id="git_conn"): Pulls the latest changes from a Git repository.
• push_backup(local_path, repo_name, databases, conn_id="git_conn"): Pushes database backups to a Git repository.
• purge_old_backups(local_path, repo_name, conn_id="git_conn"): Deletes backups older than the configured retention period and commits the changes.

Configuration

• Uses Airflow’s BaseHook to retrieve Git connection details dynamically.
• Retrieves the backup retention period from the backup_retention_days Airflow variable (default: 30 days).
• Automatically configures Git user details for committing changes.

Usage

• Automates backup management by storing database dumps in Git.
• Ensures that outdated backups are removed efficiently.
• Can be scheduled within an Airflow DAG for periodic execution.