Re: [pve-devel] [PATCH proxmox 1/2] notify: api: allow resetting built-in targets when they are referenced

[Wolfgang Bumiller <w.bumiller@proxmox.com>]

On Thu, Dec 14, 2023 at 01:42:07PM +0100, Lukas Wagner wrote:
> by a matcher.

^ this line should be part of the subject

> 
> In the 'delete'-handler targets, we check if a
> target is still referenced by a matcher - if it is, we return an
> error. For built-in targets, this is actually not necessary, since
> 'deleting' a built-in only resets it to its default settings - it will
> continue to exist after that.
> The user could easily trigger this if 'mail-to-root', which is
> referenced by 'default-matcher' is modified and then reset to its
> defaults: An error is shown, the built-in target is not reset.
> 
> This commit disables this check if it is a built-in target.
> 
> Renamed the helper 'ensure_unused' to 'ensure_safe_to_delete' in the
> process.
> 
> Also fixed the tests in api::test - they were never executed due to a
> faulty #[cfg] directive.
> 
> Signed-off-by: Lukas Wagner <l.wagner@proxmox.com>
> ---
>  proxmox-notify/src/api/gotify.rs   |  2 +-
>  proxmox-notify/src/api/mod.rs      | 74 ++++++++++++++++++++++--------
>  proxmox-notify/src/api/sendmail.rs |  2 +-
>  proxmox-notify/src/api/smtp.rs     |  2 +-
>  4 files changed, 59 insertions(+), 21 deletions(-)
> 
> diff --git a/proxmox-notify/src/api/gotify.rs b/proxmox-notify/src/api/gotify.rs
> index 98ff255..a93a024 100644
> --- a/proxmox-notify/src/api/gotify.rs
> +++ b/proxmox-notify/src/api/gotify.rs
> @@ -136,7 +136,7 @@ pub fn update_endpoint(
>  pub fn delete_gotify_endpoint(config: &mut Config, name: &str) -> Result<(), HttpError> {
>      // Check if the endpoint exists
>      let _ = get_endpoint(config, name)?;
> -    super::ensure_unused(config, name)?;
> +    super::ensure_safe_to_delete(config, name)?;
>  
>      remove_private_config_entry(config, name)?;
>      config.config.sections.remove(name);
> diff --git a/proxmox-notify/src/api/mod.rs b/proxmox-notify/src/api/mod.rs
> index 762d448..919dcb9 100644
> --- a/proxmox-notify/src/api/mod.rs
> +++ b/proxmox-notify/src/api/mod.rs
> @@ -3,7 +3,7 @@ use std::collections::HashSet;
>  
>  use proxmox_http_error::HttpError;
>  
> -use crate::Config;
> +use crate::{Config, Origin};
>  
>  pub mod common;
>  #[cfg(feature = "gotify")]
> @@ -111,7 +111,26 @@ fn get_referrers(config: &Config, entity: &str) -> Result<HashSet<String>, HttpE
>      Ok(referrers)
>  }
>  
> -fn ensure_unused(config: &Config, entity: &str) -> Result<(), HttpError> {
> +fn ensure_safe_to_delete(config: &Config, entity: &str) -> Result<(), HttpError> {
> +    if let Some(entity_config) = config.config.sections.get(entity) {
> +        let origin: Option<Origin> = entity_config
> +            .1
> +            .as_object()
> +            .and_then(|obj| obj.get("origin"))
> +            .cloned()
> +            .and_then(|origin_value| serde_json::from_value(origin_value).ok());

^ .cloned() should not be necessary, Value and &Value implement
`Deserialize_r_`, so you can use:

    .and_then(|origin_value| Origin::deserialize(origin_value).ok());

Additionally, Value returns a valid `Null` value when trying to index a
non-object as well as when the key does not exist in the object, so it
should be possible to do replace all of the above and the line below
with:

    if let Some(origin) = Origin::deserialize(&entity_config.1["origin"]) {

> +        if let Some(origin) = origin {
> +            // Built-ins are never actually removed, only reset to their default
> +            // It is thus safe to do the reset if another entity depends
> +            // on it
> +            if origin == Origin::Builtin || origin == Origin::ModifiedBuiltin {
> +                return Ok(());
> +            }
> +        }
> +    } else {
> +        http_bail!(NOT_FOUND, "entity '{entity}' does not exist");
> +    }
> +
>      let referrers = get_referrers(config, entity)?;
>  
>      if !referrers.is_empty() {
> @@ -191,31 +210,31 @@ mod test_helpers {