resolvconf error leads to creation of multiple WireGuard network interfaces

[moubctez]

When there is a problem with execution of resolvconf, defguard-service does not clean up existing WireGuard network interfaces.

Ubuntu 24.04:

From defguard-service logs:

{"timestamp":"2025-09-24T09:48:19.260644Z","level":"DEBUG","fields":{"message":"Starting DNS servers configuration for interface wg1, DNS: [1.1.1.1], search domains: []","log.target":"defguard_wireguard_rs::utils","log.module_path":"defguard_wireguard_rs::utils","log.file":"/srv/github/defguard/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/defguard_wireguard_rs-0.7.6/src/utils.rs","log.line":34},"target":"defguard_wireguard_rs::utils","span":{"interface_name":"wg1","name":"create_interface"},"spans":[{"name":"defguard_service"},{"interface_name":"wg1","name":"create_interface"}]}
{"timestamp":"2025-09-24T09:48:19.260676Z","level":"DEBUG","fields":{"message":"Executing command resolvconf with args: [\"-a\", \"wg1\", \"-m\", \"0\", \"-x\"]","log.target":"defguard_wireguard_rs::utils","log.module_path":"defguard_wireguard_rs::utils","log.file":"/srv/github/defguard/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/defguard_wireguard_rs-0.7.6/src/utils.rs","log.line":45},"target":"defguard_wireguard_rs::utils","span":{"interface_name":"wg1","name":"create_interface"},"spans":[{"name":"defguard_service"},{"interface_name":"wg1","name":"create_interface"}]}
{"timestamp":"2025-09-24T09:48:19.273528Z","level":"DEBUG","fields":{"message":"Command resolvconf spawned successfully, proceeding with writing nameservers and search domains to its stdin","log.target":"defguard_wireguard_rs::utils","log.module_path":"defguard_wireguard_rs::utils","log.file":"/srv/github/defguard/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/defguard_wireguard_rs-0.7.6/src/utils.rs","log.line":50},"target":"defguard_wireguard_rs::utils","span":{"interface_name":"wg1","name":"create_interface"},"spans":[{"name":"defguard_service"},{"interface_name":"wg1","name":"create_interface"}]}
{"timestamp":"2025-09-24T09:48:19.284351Z","level":"DEBUG","fields":{"message":"Adding nameserver entry: 1.1.1.1","log.target":"defguard_wireguard_rs::utils","log.module_path":"defguard_wireguard_rs::utils","log.file":"/srv/github/defguard/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/defguard_wireguard_rs-0.7.6/src/utils.rs","log.line":56},"target":"defguard_wireguard_rs::utils","span":{"interface_name":"wg1","name":"create_interface"},"spans":[{"name":"defguard_service"},{"interface_name":"wg1","name":"create_interface"}]}
{"timestamp":"2025-09-24T09:48:19.284564Z","level":"DEBUG","fields":{"message":"Waiting for resolvconf command to finish","log.target":"defguard_wireguard_rs::utils","log.module_path":"defguard_wireguard_rs::utils","log.file":"/srv/github/defguard/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/defguard_wireguard_rs-0.7.6/src/utils.rs","log.line":64},"target":"defguard_wireguard_rs::utils","span":{"interface_name":"wg1","name":"create_interface"},"spans":[{"name":"defguard_service"},{"interface_name":"wg1","name":"create_interface"}]}
{"timestamp":"2025-09-24T09:48:19.416786Z","level":"ERROR","fields":{"message":"Failed to configure DNS for WireGuard interface wg1: DNS error: Failed to execute resolvconf command while setting DNS servers and search domains: exit status: 1"},"target":"defguard_client::service","span":{"interface_name":"wg1","name":"create_interface"},"spans":[{"name":"defguard_service"},{"interface_name":"wg1","name":"create_interface"}]}

NB: the actual problem with resolvconf is this: Failed to set DNS configuration: Unit dbus-org.freedesktop.resolve1.service not found..