bug: filter out variable data from URI metric

Closes #420

src/web/middleware/sentry.rs

@@ -3,6 +3,7 @@ use std::{cell::RefCell, rc::Rc};
 use actix_service::{Service, Transform};
 use actix_web::{
     dev::{ServiceRequest, ServiceResponse},
+    http::uri::Uri,
     Error, HttpMessage,
 };
 use futures::{
@@ -12,6 +13,8 @@ use futures::{
 
 use crate::error::ApiError;
 use crate::web::tags::Tags;
+use lazy_static::lazy_static;
+use regex;
 
 pub struct SentryWrapper;
 
@@ -52,6 +55,28 @@ pub struct SentryWrapperMiddleware<S> {
     service: Rc<RefCell<S>>,
 }
 
+impl<S, B> SentryWrapperMiddleware<S>
+where
+    S: Service<Request = ServiceRequest, Response = ServiceResponse<B>, Error = Error> + 'static,
+    S::Future: 'static,
+    B: 'static,
+{
+    fn clean_uri(&self, uri: &Uri) -> String {
+        // Remove the variable userID and batch tokens from the URI tags
+        lazy_static! {
+            // most values are either "=true" or a lower case hex string.
+            static ref RE: regex::Regex = regex::Regex::new(r"=[a-z\d]{5,}").unwrap();
+        }
+        let trimmed = uri
+            .to_string()
+            .split("/")
+            .collect::<Vec<&str>>()
+            .split_off(3)
+            .join("/");
+        RE.replace_all(&trimmed, "=###").to_owned().to_string()
+    }
+}
+
 impl<S, B> Service for SentryWrapperMiddleware<S>
 where
     S: Service<Request = ServiceRequest, Response = ServiceResponse<B>, Error = Error> + 'static,
@@ -69,7 +94,7 @@ where
 
     fn call(&mut self, sreq: ServiceRequest) -> Self::Future {
         let mut tags = Tags::from_request_head(sreq.head());
-        let uri = sreq.head().uri.to_string();
+        let uri = self.clean_uri(&sreq.head().uri);
         sreq.extensions_mut().insert(tags.clone());
 
         Box::new(self.service.call(sreq).and_then(move |sresp| {