first pass at request scoped tracing

backend/src/api/mod.rs

@@ -88,8 +88,8 @@ pub enum Error {
     #[error("invalid webmention: {0}")]
     InvalidWebMention(String),
 
-    #[error("can't switch to the same fronter")]
+    #[error("can't switch to the same fronter {0}")]
-    SameFronter,
+    SameFronter(String),
 }
 
 pub type Result<T = ()> = std::result::Result<T, Error>;
@@ -99,7 +99,7 @@ impl<'a> Responder<'a> for Error {
         error!("{}", self);
         match self {
             Error::NotFound => Err(Status::NotFound),
-            Error::InvalidWebMention(_) | Error::SameFronter => Err(Status::BadRequest),
+            Error::InvalidWebMention(_) | Error::SameFronter(_) => Err(Status::BadRequest),
             _ => Err(Status::InternalServerError),
         }
     }

backend/src/api/switch.rs

@@ -132,7 +132,7 @@ pub fn switch(
         .ok_or_else(|| Error::NotFound)?;
 
     if member.cmene == to.cmene {
-        return Err(Error::SameFronter);
+        return Err(Error::SameFronter(member.cmene));
     }
 
     let now = Utc::now().naive_utc();

backend/src/lib.rs

@@ -21,6 +21,7 @@ pub const APPLICATION_NAME: &str = concat!(
 pub mod api;
 pub mod models;
 pub mod paseto;
+pub mod rocket_trace;
 pub mod schema;
 pub mod web;
 

backend/src/main.rs

@@ -11,7 +11,7 @@ use rocket_contrib::helmet::SpaceHelmet;
 use rocket_cors::{AllowedHeaders, AllowedOrigins};
 use rocket_prometheus::PrometheusMetrics;
 
-use ::mi::{api, paseto, web::*, MainDatabase, APPLICATION_NAME};
+use ::mi::{api, paseto, rocket_trace::*, web::*, MainDatabase, APPLICATION_NAME};
 
 #[get("/.within/botinfo")]
 fn botinfo() -> &'static str {
@@ -60,6 +60,7 @@ fn main() -> Result<()> {
         .attach(cors)
         .attach(MainDatabase::fairing())
         .attach(SpaceHelmet::default())
+        .attach(TraceRequest {})
         .attach(paseto::ed25519_keypair())
         .attach(DiscordWebhook::fairing())
         .attach(Mastodon::fairing())

backend/src/rocket_trace.rs

@@ -0,0 +1,91 @@
+use rocket::fairing::{Fairing, Info, Kind};
+use rocket::http::{ContentType, Header, Method, Status};
+use rocket::{Data, Request, Response};
+use rusty_ulid::generate_ulid_string;
+use std::mem;
+use tracing::{span, span::Entered, Level, Span};
+
+struct SpanWrapper<'a> {
+    span: Box<Span>,
+    entered: Entered<'a>,
+}
+
+pub struct TraceRequest;
+
+impl Fairing for TraceRequest {
+    fn info(&self) -> Info {
+        Info {
+            name: "Tracing spans per request",
+            kind: Kind::Request | Kind::Response,
+        }
+    }
+
+    fn on_request(&self, request: &mut Request, _: &Data) {
+        let reqid: String = match request.headers().get_one("X-Request-Id") {
+            Some(reqid) => reqid.to_string(),
+            None => {
+                let reqid = generate_ulid_string();
+                request.add_header(Header::new("X-Request-Id", reqid.clone()));
+                reqid
+            }
+        };
+
+        request.local_cache(|| {
+            let span = span!(
+                Level::INFO,
+                "request",
+                method = &request.method().to_string()[..],
+                uri = &request.uri().to_string()[..],
+                addr = &request
+                    .client_ip()
+                    .map(|ip| ip.to_string())
+                    .unwrap_or("unknown".to_string())[..],
+                request_id = &reqid[..],
+            );
+            let span = Box::new(span);
+            let entered = span.enter();
+            let entered_lt = unsafe { mem::transmute::<_, Entered<'static>>(entered) };
+
+            Box::new(SpanWrapper {
+                entered: entered_lt,
+                span: span,
+            })
+        });
+    }
+
+    fn on_response(&self, request: &Request, response: &mut Response) {
+        let span: &Box<SpanWrapper> = request.local_cache(|| {
+            Box::new({
+                let span = error_span!(
+                    "somehow the span wasn't put into the request, neat",
+                    method = &request.method().to_string()[..],
+                    uri = &request.uri().to_string()[..],
+                    address = &request
+                        .real_ip()
+                        .map(|ip| ip.to_string())
+                        .unwrap_or("unknown".to_string())[..],
+                );
+
+                let span = Box::new(span);
+                let entered = span.enter();
+                let entered_lt = unsafe { mem::transmute::<_, Entered<'static>>(entered) };
+
+                SpanWrapper {
+                    entered: entered_lt,
+                    span: span,
+                }
+            })
+        });
+        match request.headers().get_one("X-Request-Id") {
+            Some(reqid) => {
+                response.set_header(Header::new("X-Request-Id", format!("{}", reqid)));
+            }
+            None => {}
+        };
+        info!(
+            status_code = &response.status().code,
+            status_reason = response.status().reason
+        );
+        drop(span);
+    }
+}