fix ratelimits

services/api/src/middleware/ratelimit.lua

@@ -1,12 +1,13 @@
--- Copyright (c) 2017 Pavel Pravosud
+-- this script has side-effects, so it requires replicate commands mode
--- https://github.com/rwz/redis-gcra/blob/master/vendor/perform_gcra_ratelimit.lua
+-- redis.replicate_commands()
 
 local rate_limit_key = KEYS[1]
 local burst = ARGV[1]
 local rate = ARGV[2]
 local period = ARGV[3]
--- local cost = tonumber(ARGV[4])
+
-local cost = 1
+-- we're only ever asking for 1 request at a time
+local cost = 1 --local cost = tonumber(ARGV[4])
 
 local emission_interval = period / rate
 local increment = emission_interval * cost
@@ -44,7 +45,7 @@ if remaining < 0 then
     local retry_after = diff * -1
     return {
         0, -- remaining
-        retry_after,
+        tostring(retry_after),
         reset_after,
     }
 end
@@ -54,4 +55,8 @@ if reset_after > 0 then
     redis.call("SET", rate_limit_key, new_tat, "EX", math.ceil(reset_after))
 end
 local retry_after = -1
-return {remaining, retry_after, reset_after}
+return {
+    remaining,
+    tostring(retry_after),
+    reset_after
+}

services/api/src/middleware/ratelimit.rs

@@ -88,7 +88,7 @@ pub async fn do_request_ratelimited<B>(
         // local burst = ARGV[1]
         // local rate = ARGV[2]
         // local period = ARGV[3]
-        // return {remaining, retry_after, reset_after}
+        // return {remaining, tostring(retry_after), reset_after}
         let resp = redis
             .evalsha::<(i32, String, u64), String, Vec<&str>, Vec<i32>>(
                 scriptsha,
@@ -99,14 +99,21 @@ pub async fn do_request_ratelimited<B>(
 
         match resp {
             Ok((mut remaining, retry_after, reset_after)) => {
+                // redis's lua doesn't support returning floats
+                let retry_after: f64 = retry_after
+                    .parse()
+                    .expect("got something that isn't a f64 from redis");
+
                 let mut response = if remaining > 0 {
                     next.run(request).await
                 } else {
+                    println!("{}", reset_after);
                     json_err(
                         StatusCode::TOO_MANY_REQUESTS,
                         format!(
                             // todo: the retry_after is horribly wrong
-                            r#"{{"message":"429: too many requests","retry_after":{retry_after}}}"#
+                            r#"{{"message":"429: too many requests","retry_after":{},"code":0}}"#,
+                            (retry_after * 1_000_f64).ceil() as u64
                         ),
                     )
                 };