(unfinished) Download wwwroot of Linux Web App on Azure using ssh and tar

backup-wwwroot.py

import os
import sys
import time
import subprocess
import re
import paramiko
from paramiko import SSHClient, AutoAddPolicy

REMOTE_FILE_OUTPUT = "/home/site/wwwroot.tar"

def cleanup(session_name, ssh_client, screen_pid):
    try:
        ssh_client.exec_command("exit")  # Exit the remote session gracefully
        ssh_client.close()
        print("SSH connection closed.")
    except Exception as e:
        print(f"Error during cleanup: {str(e)}")

    try:
        os.remove(f"{session_name}.log")  # Remove the log file
        print("Log file removed.")
    except Exception as e:
        print(f"Error removing log file: {str(e)}")

    try:
        # Terminate the screen session
        subprocess.run(f"screen -S {session_name} -X quit", shell=True)
        print("Screen session terminated.")
    except Exception as e:
        print(f"Error terminating screen session: {str(e)}")

    print("Script terminated. Cleanup completed.")

def main():
    if len(sys.argv) != 4:
        print("Usage: python3 backup-wwwroot.py SubscriptionId ResourceGroup AppName")
        sys.exit(1)

    subscription_id = sys.argv[1]
    resource_group = sys.argv[2]
    app_name = sys.argv[3]

    timestamp = time.strftime("%Y%m%d%H%M%S")
    session_name = f"remote-connection-session-{timestamp}"
    file_output = f"{app_name}-wwwroot.tar"

    try:
        # Create a detached screen session for the Azure CLI command
        screen_cmd = (
            f"screen -S {session_name} -d -m bash -c 'az webapp create-remote-connection "
            f"--subscription {subscription_id} --resource-group {resource_group} -n {app_name} "
            f"> {session_name}.log 2>&1'"
        )
        subprocess.run(screen_cmd, shell=True)
        print("Azure CLI command started.")

        # Wait up to 60 seconds for "SSH is available" message
        timeout = 60
        elapsed = 0
        while elapsed < timeout:
            time.sleep(1)
            elapsed += 1

            # Check if "SSH is available" is in the screen session output file
            if os.path.exists(f"{session_name}.log"):
                with open(f"{session_name}.log", "r") as log_file:
                    log_content = log_file.read()
                    match = re.search(r"SSH is available \{ username: ([^,]+), password: ([^}]+) \}", log_content)
                    addr_match = re.search(r"Opening tunnel on addr: (\S+)", log_content)
                    port_match = re.search(r"Opening tunnel on port: (\d+)", log_content)

                    if match and addr_match and port_match:
                        username = match.group(1).strip()
                        password = match.group(2).strip()
                        addr = addr_match.group(1).strip()
                        port = port_match.group(1).strip()
                        print("SSH connection details retrieved.")
                        break

        if elapsed >= timeout:
            print(f"Unable to establish a connection within {timeout} seconds.")
            sys.exit(1)

        # Establish SSH connection to the Azure Web App using extracted details
        ssh_client = SSHClient()
        ssh_client.set_missing_host_key_policy(AutoAddPolicy())

        ssh_client.connect(
            hostname=addr,          # Extracted addr
            port=int(port),         # Extracted port
            username=username,      # Extracted username
            password=password       # Extracted password
        )
        print("SSH connection established.")

        # Execute the command on the remote server to tar the files
        stdin, stdout, stderr = ssh_client.exec_command(f"tar -c --warning=no-file-changed -f {REMOTE_FILE_OUTPUT} --totals /home/site/wwwroot", get_pty=True)
        print("Tar command is being executed. Waiting for it to finish...")

        # Wait for the command to finish
        exit_status = stdout.channel.recv_exit_status()

        # Check the exit status
        if exit_status == 0:
            print("Command executed successfully")
        else:
            print(f"Command failed with exit status {exit_status}")

        print("Files on the remote server are archived.")

        # Create an SFTP session for file transfer
        sftp = ssh_client.open_sftp()

        # Copy the tar file to the local machine
        sftp.get(REMOTE_FILE_OUTPUT, f"{app_name}-wwwroot.tar")
        print("Files copied successfully from the remote server.")


    except Exception as e:
        print(f"Error: {str(e)}")
        print("Unable to establish a connection or transfer files.")
    finally:
        cleanup(session_name, ssh_client, os.getpid())

if __name__ == "__main__":
    main()