notify: add mechanisms for email message forwarding

As preparation for the integration of `proxmox-mail-foward` into the
notification system, this commit makes a few changes that allow us to
forward raw email messages (as passed from postfix).

For mail-based notification targets, the email will be forwarded
as-is, including all headers. The only thing that changes is the
message envelope.
For other notification targets, the mail is parsed using the
`mail-parser` crate, which allows us to extract a subject and a body.
As a body we use the plain-text version of the mail. If an email is
HTML-only, the `mail-parser` crate will automatically attempt to
transform the HTML into readable plain text.

Signed-off-by: Lukas Wagner <l.wagner@proxmox.com>
This commit is contained in:
Lukas Wagner 2023-11-14 13:59:18 +01:00 committed by Thomas Lamprecht
parent d20d9ec1aa
commit 5f7ac875f6
5 changed files with 52 additions and 0 deletions

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@ -64,6 +64,7 @@ lazy_static = "1.4"
ldap3 = { version = "0.11", default-features = false }
libc = "0.2.107"
log = "0.4.17"
mail-parser = "0.8.2"
native-tls = "0.2"
nix = "0.26.1"
once_cell = "1.3.1"

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@ -12,6 +12,7 @@ anyhow.workspace = true
handlebars = { workspace = true }
lazy_static.workspace = true
log.workspace = true
mail-parser = { workspace = true, optional = true }
once_cell.workspace = true
openssl.workspace = true
proxmox-http = { workspace = true, features = ["client-sync"], optional = true }
@ -28,5 +29,6 @@ serde_json.workspace = true
[features]
default = ["sendmail", "gotify"]
mail-forwarder = ["dep:mail-parser"]
sendmail = ["dep:proxmox-sys"]
gotify = ["dep:proxmox-http"]

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@ -19,6 +19,7 @@ fn severity_to_priority(level: Severity) -> u32 {
Severity::Notice => 3,
Severity::Warning => 5,
Severity::Error => 9,
Severity::Unknown => 3,
}
}
@ -94,6 +95,8 @@ impl Endpoint for GotifyEndpoint {
(rendered_title, rendered_message)
}
#[cfg(feature = "mail-forwarder")]
Content::ForwardedMail { title, body, .. } => (title.clone(), body.clone()),
};
// We don't have a TemplateRenderer::Markdown yet, so simply put everything

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@ -134,6 +134,11 @@ impl Endpoint for SendmailEndpoint {
)
.map_err(|err| Error::NotifyFailed(self.config.name.clone(), err.into()))
}
#[cfg(feature = "mail-forwarder")]
Content::ForwardedMail { raw, uid, .. } => {
proxmox_sys::email::forward(&recipients_str, &mailfrom, raw, *uid)
.map_err(|err| Error::NotifyFailed(self.config.name.clone(), err.into()))
}
}
}

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@ -102,6 +102,8 @@ pub enum Severity {
Warning,
/// Error
Error,
/// Unknown severity (e.g. forwarded system mails)
Unknown,
}
impl Display for Severity {
@ -111,6 +113,7 @@ impl Display for Severity {
Severity::Notice => f.write_str("notice"),
Severity::Warning => f.write_str("warning"),
Severity::Error => f.write_str("error"),
Severity::Unknown => f.write_str("unknown"),
}
}
}
@ -123,6 +126,7 @@ impl FromStr for Severity {
"notice" => Ok(Self::Notice),
"warning" => Ok(Self::Warning),
"error" => Ok(Self::Error),
"unknown" => Ok(Self::Unknown),
_ => Err(Error::Generic(format!("invalid severity {s}"))),
}
}
@ -148,6 +152,18 @@ pub enum Content {
/// Data that can be used for template rendering.
data: Value,
},
#[cfg(feature = "mail-forwarder")]
ForwardedMail {
/// Raw mail contents
raw: Vec<u8>,
/// Fallback title
title: String,
/// Fallback body
body: String,
/// UID to use when calling sendmail
#[allow(dead_code)] // Unused in some feature flag permutations
uid: Option<u32>,
},
}
#[derive(Debug, Clone)]
@ -190,6 +206,31 @@ impl Notification {
},
}
}
#[cfg(feature = "mail-forwarder")]
pub fn new_forwarded_mail(raw_mail: &[u8], uid: Option<u32>) -> Result<Self, Error> {
let message = mail_parser::Message::parse(raw_mail)
.ok_or_else(|| Error::Generic("could not parse forwarded email".to_string()))?;
let title = message.subject().unwrap_or_default().into();
let body = message.body_text(0).unwrap_or_default().into();
Ok(Self {
// Unfortunately we cannot reasonably infer the severity from the
// mail contents, so just set it to the highest for now so that
// it is not filtered out.
content: Content::ForwardedMail {
raw: raw_mail.into(),
title,
body,
uid,
},
metadata: Metadata {
severity: Severity::Unknown,
additional_fields: Default::default(),
timestamp: proxmox_time::epoch_i64(),
},
})
}
}
/// Notification configuration