def rotate(endpoint_name, source, new_certificate_name, old_certificate_name, message, commit):
    """
    Rotates an endpoint and reissues it if it has not already been replaced. If it has
    been replaced, will use the replacement certificate for the rotation.
    """
    if commit:
        click.echo("[!] Running in COMMIT mode.")

    click.echo("[+] Starting endpoint rotation.")

    status = FAILURE_METRIC_STATUS

    log_data = {
        "function": f"{__name__}.{sys._getframe().f_code.co_name}",
    }

    try:
        old_cert = validate_certificate(old_certificate_name)
        new_cert = validate_certificate(new_certificate_name)
        if source:
            endpoint = validate_endpoint_from_source(endpoint_name, source)
        else:
            try:
                endpoint = validate_endpoint(endpoint_name)
            except MultipleResultsFound as e:
                click.echo(f"[!] Multiple endpoints found with name {endpoint_name}, try narrowing the search down to an endpoint from a specific source by re-running this command with the --source flag.")
                log_data["message"] = "Multiple endpoints found with same name, unable to perform rotation"
                log_data["duplicated_endpoint_name"] = endpoint_name
                current_app.logger.info(log_data)
                raise

        if endpoint and new_cert:
            click.echo(
                f"[+] Rotating endpoint: {endpoint.name} to certificate {new_cert.name}"
            )
            log_data["message"] = "Rotating one endpoint"
            log_data["endpoint"] = endpoint.dnsname
            log_data["certificate"] = new_cert.name
            request_rotation(endpoint, new_cert, message, commit)
            current_app.logger.info(log_data)

        elif old_cert and new_cert:
            click.echo(f"[+] Rotating all endpoints from {old_cert.name} to {new_cert.name}")
            log_data["certificate"] = new_cert.name
            log_data["certificate_old"] = old_cert.name
            log_data["message"] = "Rotating endpoint from old to new cert"
            for endpoint in old_cert.endpoints:
                click.echo(f"[+] Rotating {endpoint.name}")
                log_data["endpoint"] = endpoint.dnsname
                request_rotation(endpoint, new_cert, message, commit)
                current_app.logger.info(log_data)

        else:
            # No certificate name or endpoint is provided. We will now fetch all endpoints,
            # which are associated with a certificate that has been replaced
            click.echo("[+] Rotating all endpoints that have new certificates available")
            for endpoint in endpoint_service.get_all_pending_rotation():

                log_data["message"] = "Rotating endpoint from old to new cert"
                if len(endpoint.certificate.replaced) > 1:
                    log_data["message"] = f"Multiple replacement certificates found, going with the first one out of " \
                                          f"{len(endpoint.certificate.replaced)}"

                log_data["endpoint"] = endpoint.dnsname
                log_data["certificate"] = endpoint.certificate.replaced[0].name
                click.echo(
                    f"[+] Rotating {endpoint.name} to {endpoint.certificate.replaced[0].name}"
                )
                request_rotation(endpoint, endpoint.certificate.replaced[0], message, commit)
                current_app.logger.info(log_data)

        status = SUCCESS_METRIC_STATUS
        click.echo("[+] Done!")

    except Exception as e:
        capture_exception(
            extra={
                "old_certificate_name": str(old_certificate_name),
                "new_certificate_name": str(new_certificate_name),
                "endpoint_name": str(endpoint_name),
                "message": str(message),
            }
        )

    metrics.send(
        "endpoint_rotation_job",
        "counter",
        1,
        metric_tags={
            "status": status,
            "old_certificate_name": str(old_certificate_name),
            "new_certificate_name": str(new_certificate_name),
            "endpoint_name": str(endpoint_name),
            "message": str(message),
            "endpoint": str(globals().get("endpoint")),
        },
    )

    Rotates an endpoint and reissues it if it has not already been replaced. If it has
    been replaced, will use the replacement certificate for the rotation.
    
lemur/certificates/cli.py