Read Postgres Configuration File

Read and Display Postgres configuration information

The following script reads the Postgresql configuration file and displays key settings. Results are sent to the console and an outfile. You can also specify the postresql.conf file location via parameter.

import re
import sys
import subprocess
import json

def get_node_name():
    # Try to get the cluster name using the `pg_lsclusters` command
    try:
        output = subprocess.check_output(['pg_lsclusters', '-h'], universal_newlines=True)
        # Extract the cluster name (which is typically "main" in default installations)
        cluster_name = output.splitlines()[1].split()[-1]
        return cluster_name
    except:
        return "Unknown"

def read_postgres_conf(file_path):
    # Define the settings we're interested in
    settings = [
        "listen_addresses", "port", "max_connections", "shared_buffers", 
        "work_mem", "maintenance_work_mem", "wal_level", "max_wal_size", "min_wal_size"
        "archive_mode", "log_statement", "log_duration", "hot_standby","synchronous_commit",
        "autovacuum", "log_timezone", "timezone", "ssl", "Password_encryption",
        "effective_cache_size","random_page_cost", "seq_page_cost"
    ]
    
    # Initialize a dictionary with "Not Set" as default for all settings and empty comments
    values = {setting: {"value": "Not Set", "comment": ""} for setting in settings}

    try:
        with open(file_path, 'r') as file:
            for line in file:
                # Remove leading and trailing whitespaces
                line = line.strip()

                # Skip empty lines
                if not line:
                    continue

                for setting in settings:
                    if line.startswith(setting):
                        # Extract the value and possible comment using a regular expression
                        match = re.search(r'^\s*{}\s*=\s*([^#\s]*)\s*(?:#\s*(.*))?'.format(setting), line)
                        if match:
                            values[setting]["value"] = match.group(1).strip("'\"")
                            if match.group(2):
                                values[setting]["comment"] = match.group(2).strip()
    except FileNotFoundError:
        print(f"Error: The file '{file_path}' was not found.")
        return

    return values

if __name__ == "__main__":
    default_path = "/etc/postgresql/15/main/postgresql.conf"
    output_file = "/tmp/linuxverification.json"
    
    if len(sys.argv) == 2 and sys.argv[1] in ["-h", "--help"]:
        print("Usage: python postgresverification.py [path_to_postgresql.conf]")
        print(f"Default path if not specified: {default_path}")
        print("Example: python postgresverification.py /path/to/your/postgresql.conf")
    else:
        file_path = sys.argv[1] if len(sys.argv) > 1 else default_path
        values = read_postgres_conf(file_path)

        if values:
            # Get the node name
            node_name = get_node_name()
            output_data = {
                "Postgres Node Name": node_name,
                "Settings": values
            }

           # Output to the console
            print(f"Postgres Node Name: {node_name}\n")
            print("{:<20} | {:<15} | {}".format("Setting", "Current Value", "Comment"))
            print("-" * 65)
            for setting, data in values.items():
                print("{:<20} | {:<15} | {}".format(setting, data["value"], data["comment"]))
       

            # Append the results to the file in JSON format
            with open(output_file, 'a') as json_file:
                json_file.write(json.dumps(output_data, indent=4))
                json_file.write('\n')  # Separate entries by a newline

            print(f"Results appended to: {output_file}")