[pve-devel] [PATCH v4 proxmox 04/69] notify: preparation for the first endpoint plugin

[Lukas Wagner <l.wagner@proxmox.com>]

Signed-off-by: Lukas Wagner <l.wagner@proxmox.com>
---

Notes:
    Changes since v3:
      - Derive Clone for Config
      - Remove private_digest from Config
      - Add explanatory comment on why Rc<RecCell<Vec<Notification>>> is
        needed in the test code
      - Avoid linear search in Vec for private_configs
      - Minor stylistic touchups

 Cargo.toml                          |   1 +
 proxmox-notify/Cargo.toml           |   9 +
 proxmox-notify/src/config.rs        |  51 +++++
 proxmox-notify/src/endpoints/mod.rs |   0
 proxmox-notify/src/lib.rs           | 301 ++++++++++++++++++++++++++++
 proxmox-notify/src/schema.rs        |  21 ++
 6 files changed, 383 insertions(+)
 create mode 100644 proxmox-notify/src/config.rs
 create mode 100644 proxmox-notify/src/endpoints/mod.rs
 create mode 100644 proxmox-notify/src/schema.rs

diff --git a/Cargo.toml b/Cargo.toml
index 317593f0..ef8a050a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -93,6 +93,7 @@ proxmox-lang = { version = "1.1", path = "proxmox-lang" }
 proxmox-rest-server = { version = "0.4.0", path = "proxmox-rest-server" }
 proxmox-router = { version = "1.3.1", path = "proxmox-router" }
 proxmox-schema = { version = "1.3.7", path = "proxmox-schema" }
+proxmox-section-config = { version = "1.0.2", path = "proxmox-section-config" }
 proxmox-serde = { version = "0.1.1", path = "proxmox-serde", features = [ "serde_json" ] }
 proxmox-sortable-macro = { version = "0.1.2", path = "proxmox-sortable-macro" }
 proxmox-sys = { version = "0.5.0", path = "proxmox-sys" }
diff --git a/proxmox-notify/Cargo.toml b/proxmox-notify/Cargo.toml
index 2e69d5b0..2cd6278a 100644
--- a/proxmox-notify/Cargo.toml
+++ b/proxmox-notify/Cargo.toml
@@ -8,3 +8,12 @@ repository.workspace = true
 exclude.workspace = true
 
 [dependencies]
+lazy_static.workspace = true
+log.workspace = true
+openssl.workspace = true
+proxmox-schema = { workspace = true, features = ["api-macro", "api-types"]}
+proxmox-section-config = { workspace = true }
+proxmox-sys.workspace = true
+regex.workspace = true
+serde.workspace = true
+serde_json.workspace = true
diff --git a/proxmox-notify/src/config.rs b/proxmox-notify/src/config.rs
new file mode 100644
index 00000000..362ca0fc
--- /dev/null
+++ b/proxmox-notify/src/config.rs
@@ -0,0 +1,51 @@
+use lazy_static::lazy_static;
+use proxmox_schema::{ApiType, ObjectSchema};
+use proxmox_section_config::{SectionConfig, SectionConfigData, SectionConfigPlugin};
+
+use crate::schema::BACKEND_NAME_SCHEMA;
+use crate::Error;
+
+lazy_static! {
+    pub static ref CONFIG: SectionConfig = config_init();
+    pub static ref PRIVATE_CONFIG: SectionConfig = private_config_init();
+}
+
+fn config_init() -> SectionConfig {
+    let mut config = SectionConfig::new(&BACKEND_NAME_SCHEMA);
+
+    config
+}
+
+fn private_config_init() -> SectionConfig {
+    let mut config = SectionConfig::new(&BACKEND_NAME_SCHEMA);
+
+    config
+}
+
+pub fn config(raw_config: &str) -> Result<(SectionConfigData, [u8; 32]), Error> {
+    let digest = openssl::sha::sha256(raw_config.as_bytes());
+    let data = CONFIG
+        .parse("notifications.cfg", raw_config)
+        .map_err(|err| Error::ConfigDeserialization(err.into()))?;
+    Ok((data, digest))
+}
+
+pub fn private_config(raw_config: &str) -> Result<(SectionConfigData, [u8; 32]), Error> {
+    let digest = openssl::sha::sha256(raw_config.as_bytes());
+    let data = PRIVATE_CONFIG
+        .parse("priv/notifications.cfg", raw_config)
+        .map_err(|err| Error::ConfigDeserialization(err.into()))?;
+    Ok((data, digest))
+}
+
+pub fn write(config: &SectionConfigData) -> Result<String, Error> {
+    CONFIG
+        .write("notifications.cfg", config)
+        .map_err(|err| Error::ConfigSerialization(err.into()))
+}
+
+pub fn write_private(config: &SectionConfigData) -> Result<String, Error> {
+    PRIVATE_CONFIG
+        .write("priv/notifications.cfg", config)
+        .map_err(|err| Error::ConfigSerialization(err.into()))
+}
diff --git a/proxmox-notify/src/endpoints/mod.rs b/proxmox-notify/src/endpoints/mod.rs
new file mode 100644
index 00000000..e69de29b
diff --git a/proxmox-notify/src/lib.rs b/proxmox-notify/src/lib.rs
index e69de29b..deebe046 100644
--- a/proxmox-notify/src/lib.rs
+++ b/proxmox-notify/src/lib.rs
@@ -0,0 +1,301 @@
+use std::collections::HashMap;
+use std::fmt::Display;
+
+use proxmox_schema::api;
+use proxmox_section_config::SectionConfigData;
+use serde::{Deserialize, Serialize};
+use serde_json::json;
+use serde_json::Value;
+
+use std::error::Error as StdError;
+
+mod config;
+pub mod endpoints;
+pub mod schema;
+
+#[derive(Debug)]
+pub enum Error {
+    ConfigSerialization(Box<dyn StdError + Send + Sync>),
+    ConfigDeserialization(Box<dyn StdError + Send + Sync>),
+    NotifyFailed(String, Box<dyn StdError + Send + Sync>),
+    TargetDoesNotExist(String),
+}
+
+impl Display for Error {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Error::ConfigSerialization(err) => {
+                write!(f, "could not serialize configuration: {err}")
+            }
+            Error::ConfigDeserialization(err) => {
+                write!(f, "could not deserialize configuration: {err}")
+            }
+            Error::NotifyFailed(endpoint, err) => {
+                write!(f, "could not notify via endpoint(s): {endpoint}: {err}")
+            }
+            Error::TargetDoesNotExist(target) => {
+                write!(f, "notification target '{target}' does not exist")
+            }
+        }
+    }
+}
+
+impl StdError for Error {
+    fn source(&self) -> Option<&(dyn StdError + 'static)> {
+        match self {
+            Error::ConfigSerialization(err) => Some(&**err),
+            Error::ConfigDeserialization(err) => Some(&**err),
+            Error::NotifyFailed(_, err) => Some(&**err),
+            Error::TargetDoesNotExist(_) => None,
+        }
+    }
+}
+
+#[api()]
+#[derive(Clone, Debug, Copy, Serialize, Deserialize, PartialEq, Eq, PartialOrd)]
+#[serde(rename_all = "kebab-case")]
+/// Severity of a notification
+pub enum Severity {
+    /// General information
+    Info,
+    /// A noteworthy event
+    Notice,
+    /// Warning
+    Warning,
+    /// Error
+    Error,
+}
+
+/// Notification endpoint trait, implemented by all endpoint plugins
+pub trait Endpoint {
+    /// Send a documentation
+    fn send(&self, notification: &Notification) -> Result<(), Error>;
+
+    /// The name/identifier for this endpoint
+    fn name(&self) -> &str;
+}
+
+#[derive(Debug, Clone)]
+/// Notification which can be sent
+pub struct Notification {
+    /// Notification severity
+    pub severity: Severity,
+    /// The title of the notification
+    pub title: String,
+    /// Notification text
+    pub body: String,
+    /// Additional metadata for the notification
+    pub properties: Option<Value>,
+}
+
+/// Notification configuration
+#[derive(Debug, Clone)]
+pub struct Config {
+    config: SectionConfigData,
+    private_config: SectionConfigData,
+    digest: [u8; 32],
+}
+
+impl Config {
+    /// Parse raw config
+    pub fn new(raw_config: &str, raw_private_config: &str) -> Result<Self, Error> {
+        let (config, digest) = config::config(raw_config)?;
+        let (private_config, _) = config::private_config(raw_private_config)?;
+
+        Ok(Self {
+            config,
+            digest,
+            private_config,
+        })
+    }
+
+    /// Serialize config
+    pub fn write(&self) -> Result<(String, String), Error> {
+        Ok((
+            config::write(&self.config)?,
+            config::write_private(&self.private_config)?,
+        ))
+    }
+
+    /// Returns the SHA256 digest of the configuration.
+    /// The digest is only computed once when the configuration deserialized.
+    pub fn digest(&self) -> &[u8; 32] {
+        &self.digest
+    }
+}
+
+/// Notification bus - distributes notifications to all registered endpoints
+// The reason for the split between `Config` and this struct is to make testing with mocked
+// endpoints a bit easier.
+#[derive(Default)]
+pub struct Bus {
+    endpoints: HashMap<String, Box<dyn Endpoint>>,
+}
+
+#[allow(unused_macros)]
+macro_rules! parse_endpoints_with_private_config {
+    ($config:ident, $public_config:ty, $private_config:ty, $endpoint_type:ident, $type_name:expr) => {
+        (|| -> Result<Vec<Box<dyn Endpoint>>, Error> {
+            let mut endpoints = Vec::<Box<dyn Endpoint>>::new();
+
+            let configs: Vec<$public_config> = $config
+                .config
+                .convert_to_typed_array($type_name)
+                .map_err(|err| Error::ConfigDeserialization(err.into()))?;
+
+            for config in configs {
+                match $config.private_config.sections.get(&config.name) {
+                    Some((section_type_name, private_config)) => {
+                        if $type_name != section_type_name {
+                            log::error!(
+                                "Could not instantiate endpoint '{name}': \
+                                private config has wrong type",
+                                name = config.name
+                            );
+                        }
+                        let private_config = <$private_config>::deserialize(private_config)
+                            .map_err(|err| Error::ConfigDeserialization(err.into()))?;
+
+                        endpoints.push(Box::new($endpoint_type {
+                            config,
+                            private_config: private_config.clone(),
+                        }));
+                    }
+                    None => log::error!(
+                        "Could not instantiate endpoint '{name}': \
+                            private config does not exist",
+                        name = config.name
+                    ),
+                }
+            }
+
+            Ok(endpoints)
+        })()
+    };
+}
+
+#[allow(unused_macros)]
+macro_rules! parse_endpoints_without_private_config {
+    ($config:ident, $public_config:ty, $endpoint_type:ident, $type_name:expr) => {
+        (|| -> Result<Vec<Box<dyn Endpoint>>, Error> {
+            let mut endpoints = Vec::<Box<dyn Endpoint>>::new();
+
+            let configs: Vec<$public_config> = $config
+                .config
+                .convert_to_typed_array($type_name)
+                .map_err(|err| Error::ConfigDeserialization(err.into()))?;
+
+            for config in configs {
+                endpoints.push(Box::new($endpoint_type { config }));
+            }
+
+            Ok(endpoints)
+        })()
+    };
+}
+
+impl Bus {
+    /// Instantiate notification bus from a given configuration.
+    pub fn from_config(config: &Config) -> Result<Self, Error> {
+        let mut endpoints = HashMap::new();
+
+        Ok(Bus { endpoints })
+    }
+
+    #[cfg(test)]
+    pub fn add_endpoint(&mut self, endpoint: Box<dyn Endpoint>) {
+        self.endpoints.insert(endpoint.name().to_string(), endpoint);
+    }
+
+    pub fn send(&self, target: &str, notification: &Notification) -> Result<(), Error> {
+        log::info!(
+            "sending notification with title '{title}'",
+            title = notification.title
+        );
+
+        let endpoint = self
+            .endpoints
+            .get(target)
+            .ok_or(Error::TargetDoesNotExist(target.into()))?;
+
+        endpoint.send(notification).unwrap_or_else(|e| {
+            log::error!(
+                "could not notfiy via endpoint `{name}`: {e}",
+                name = endpoint.name()
+            )
+        });
+
+        Ok(())
+    }
+
+    pub fn test_target(&self, target: &str) -> Result<(), Error> {
+        let endpoint = self
+            .endpoints
+            .get(target)
+            .ok_or(Error::TargetDoesNotExist(target.into()))?;
+
+        endpoint.send(&Notification {
+            severity: Severity::Info,
+            title: "Test notification".into(),
+            body: "This is a test of the notification target '{{ target }}'".into(),
+            properties: Some(json!({ "target": target })),
+        })?;
+
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::{cell::RefCell, rc::Rc};
+
+    use super::*;
+
+    #[derive(Default, Clone)]
+    struct MockEndpoint {
+        // Needs to be an Rc so that we can clone MockEndpoint before
+        // passing it to Bus, while still retaining a handle to the Vec
+        messages: Rc<RefCell<Vec<Notification>>>,
+    }
+
+    impl Endpoint for MockEndpoint {
+        fn send(&self, message: &Notification) -> Result<(), Error> {
+            self.messages.borrow_mut().push(message.clone());
+
+            Ok(())
+        }
+
+        fn name(&self) -> &str {
+            "mock-endpoint"
+        }
+    }
+
+    impl MockEndpoint {
+        fn messages(&self) -> Vec<Notification> {
+            self.messages.borrow().clone()
+        }
+    }
+
+    #[test]
+    fn test_add_mock_endpoint() -> Result<(), Error> {
+        let mock = MockEndpoint::default();
+
+        let mut bus = Bus::default();
+
+        bus.add_endpoint(Box::new(mock.clone()));
+
+        bus.send(
+            "mock-endpoint",
+            &Notification {
+                title: "Title".into(),
+                body: "Body".into(),
+                severity: Severity::Info,
+                properties: Default::default(),
+            },
+        )?;
+        let messages = mock.messages();
+        assert_eq!(messages.len(), 1);
+
+        Ok(())
+    }
+}
diff --git a/proxmox-notify/src/schema.rs b/proxmox-notify/src/schema.rs
new file mode 100644
index 00000000..aebffa0d
--- /dev/null
+++ b/proxmox-notify/src/schema.rs
@@ -0,0 +1,21 @@
+use proxmox_schema::api_types::{SAFE_ID_FORMAT, SINGLE_LINE_COMMENT_FORMAT};
+use proxmox_schema::{Schema, StringSchema};
+
+pub const EMAIL_SCHEMA: Schema = StringSchema::new("E-Mail Address.")
+    .format(&SINGLE_LINE_COMMENT_FORMAT)
+    .min_length(2)
+    .max_length(64)
+    .schema();
+
+pub const BACKEND_NAME_SCHEMA: Schema = StringSchema::new("Notification backend name.")
+    .format(&SAFE_ID_FORMAT)
+    .min_length(3)
+    .max_length(32)
+    .schema();
+
+pub const ENTITY_NAME_SCHEMA: Schema =
+    StringSchema::new("Name schema for endpoints, filters and groups")
+        .format(&SAFE_ID_FORMAT)
+        .min_length(2)
+        .max_length(32)
+        .schema();
-- 
2.39.2