Merge pull request #125 from xsnippet/request-id

Generate a unique id for each request and return it in the X-Request-Id header

Cargo.toml

@@ -23,3 +23,4 @@ rocket = "0.4.5"
 rocket_contrib = {version = "0.4.5", features = ["json"]}
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
+uuid = { version = "0.8.2", features = ["v4"] }

src/application.rs

@@ -3,6 +3,7 @@ use std::error::Error;
 
 use super::routes;
 use super::storage::{SqlStorage, Storage};
+use super::web::RequestIdHeader;
 
 #[derive(Debug)]
 pub struct Config {
@@ -49,5 +50,6 @@ pub fn create_app() -> Result<rocket::Rocket, Box<dyn Error>> {
     Ok(app
         .manage(Config { syntaxes })
         .manage(storage)
+        .attach(RequestIdHeader)
         .mount("/v1", routes))
 }

src/web.rs

@@ -1,3 +1,5 @@
 mod content;
+mod tracing;
 
 pub use content::{Input, NegotiatedContentType, Output};
+pub use tracing::{RequestId, RequestIdHeader};

src/web/tracing.rs

@@ -0,0 +1,48 @@
+use rocket::fairing::{Fairing, Info, Kind};
+use rocket::request::{self, FromRequest, Request};
+use rocket::{Outcome, Response};
+
+/// Unique identifier assigned to a given API request.
+pub struct RequestId(pub String);
+
+impl RequestId {
+    pub fn new() -> Self {
+        RequestId(uuid::Uuid::new_v4().to_hyphenated().to_string())
+    }
+}
+
+impl Default for RequestId {
+    fn default() -> Self {
+        RequestId::new()
+    }
+}
+
+impl<'a, 'r> FromRequest<'a, 'r> for &'a RequestId {
+    type Error = ();
+
+    fn from_request(request: &'a Request<'r>) -> request::Outcome<Self, Self::Error> {
+        // on first access, generate a new value and store it in the request cache
+        Outcome::Success(request.local_cache(RequestId::default))
+    }
+}
+
+/// Rocket fairing that returns the identifier of the API request in the
+/// X-Request-Id response header.
+pub struct RequestIdHeader;
+
+impl Fairing for RequestIdHeader {
+    fn info(&self) -> Info {
+        Info {
+            name: "X-Request-Id response header",
+            kind: Kind::Response,
+        }
+    }
+
+    fn on_response(&self, request: &Request, response: &mut Response) {
+        if let Some(request_id) = request.guard::<&RequestId>().succeeded() {
+            response.set_raw_header("X-Request-Id", request_id.0.clone());
+        } else {
+            eprintln!("Failed to generate a request id");
+        }
+    }
+}

tests/gabbits/create-snippet-errors.yaml

@@ -1,3 +1,6 @@
+common:
+  - &request_id_regex /^[0-9a-fA-F]{8}-([0-9a-fA-F]{4}-){3}[0-9a-fA-F]{12}$/
+
 fixtures:
   - XSnippetApi
 
@@ -10,6 +13,7 @@ tests:
     status: 415
     response_headers:
       content-type: application/json
+      x-request-id: *request_id_regex
     response_json_paths:
       $:
         message: "Support media types: application/json"
@@ -27,6 +31,8 @@ tests:
         - spam
         - eggs
     status: 406
+    response_headers:
+      x-request-id: *request_id_regex
 
   - name: create a new snippet (invalid HTTP method)
     PUT: /v1/snippets
@@ -40,6 +46,8 @@ tests:
         - spam
         - eggs
     status: 404
+    response_headers:
+      x-request-id: *request_id_regex
 
   - name: create a new snippet (invalid JSON)
     POST: /v1/snippets
@@ -49,6 +57,7 @@ tests:
     status: 400
     response_headers:
       content-type: application/json
+      x-request-id: *request_id_regex
     response_json_paths:
       $:
         message: "Invalid JSON"
@@ -67,6 +76,7 @@ tests:
     status: 400
     response_headers:
       content-type: application/json
+      x-request-id: *request_id_regex
     response_json_paths:
       $:
         message: "`content` - empty values not allowed."
@@ -85,6 +95,7 @@ tests:
     status: 400
     response_headers:
       content-type: application/json
+      x-request-id: *request_id_regex
     response_json_paths:
       $:
         message: "`syntax` - unallowed value cpp."
@@ -101,6 +112,7 @@ tests:
     status: 400
     response_headers:
       content-type: application/json
+      x-request-id: *request_id_regex
     response_json_paths:
       $.message: "/invalid type: string \"spam\"/"
 
@@ -119,5 +131,6 @@ tests:
     status: 400
     response_headers:
       content-type: application/json
+      x-request-id: *request_id_regex
     response_json_paths:
       $.message: "/unknown field `syntax1`/"

tests/gabbits/create-snippet.yaml

@@ -1,7 +1,8 @@
 common:
   - &datetime_regex /^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d+(\+\d{2}:\d{2})|Z$/
-  - &slug_regex /^[a-zA-Z0-9]+$/
   - &location_regex /^/v1/snippets/[a-zA-Z0-9]+$/
+  - &request_id_regex /^[0-9a-fA-F]{8}-([0-9a-fA-F]{4}-){3}[0-9a-fA-F]{12}$/
+  - &slug_regex /^[a-zA-Z0-9]+$/
 
 fixtures:
   - XSnippetApi
@@ -22,6 +23,7 @@ tests:
     response_headers:
       content-type: application/json
       location: *location_regex
+      x-request-id: *request_id_regex
     response_json_paths:
       $.id: *slug_regex
       $.title: Hello, World!
@@ -49,6 +51,7 @@ tests:
     response_headers:
       content-type: application/json
       location: *location_regex
+      x-request-id: *request_id_regex
     response_json_paths:
       $.id: *slug_regex
       $.title: Hello, World!
@@ -76,6 +79,7 @@ tests:
     response_headers:
       content-type: application/json
       location: *location_regex
+      x-request-id: *request_id_regex
     response_json_paths:
       $.id: *slug_regex
       $.title: Hello, World!
@@ -103,6 +107,7 @@ tests:
     response_headers:
       content-type: application/json
       location: *location_regex
+      x-request-id: *request_id_regex
     response_json_paths:
       $.id: *slug_regex
       $.title: Hello, World!
@@ -130,6 +135,7 @@ tests:
     response_headers:
       content-type: application/json
       location: *location_regex
+      x-request-id: *request_id_regex
     response_json_paths:
       $.id: *slug_regex
       $.title: Hello, World!
@@ -153,6 +159,7 @@ tests:
     response_headers:
       content-type: application/json
       location: *location_regex
+      x-request-id: *request_id_regex
     response_json_paths:
       $.id: *slug_regex
       $.title: Hello, World!
@@ -176,6 +183,7 @@ tests:
     response_headers:
       content-type: application/json
       location: *location_regex
+      x-request-id: *request_id_regex
     response_json_paths:
       $.id: *slug_regex
       $.title:
@@ -201,6 +209,7 @@ tests:
     response_headers:
       content-type: application/json
       location: *location_regex
+      x-request-id: *request_id_regex
     response_json_paths:
       $.id: *slug_regex
       $.title: Hello, World!
@@ -222,6 +231,7 @@ tests:
     response_headers:
       content-type: application/json
       location: *location_regex
+      x-request-id: *request_id_regex
     response_json_paths:
       $.id: *slug_regex
       $.title: