Fallback to the previous poll interval duration if no poll interval is specified.

src/githubctl/github_endpoint_watcher.rs

@@ -12,6 +12,7 @@ pub struct GithubEndpointWatcher {
     next_poll_allowed: u64,
     ratelimit_remaining: Option<u64>,
     ratelimit_reset: Option<u64>,
+    previous_poll_interval: Option<u64>,
 }
 
 impl GithubEndpointWatcher {
@@ -31,6 +32,7 @@ impl GithubEndpointWatcher {
             next_poll_allowed: 0,
             ratelimit_remaining: None,
             ratelimit_reset: None,
+            previous_poll_interval: None,
         })
     }
 
@@ -65,6 +67,9 @@ impl GithubEndpointWatcher {
         let headers = response.headers();
         let etag = headers.get(reqwest::header::ETAG).map(|x| x.to_owned());
         let poll_interval = number_header(headers.get("x-poll-interval"))?;
+        if let Some(interval) = poll_interval {
+            self.previous_poll_interval = Some(interval);
+        }
         // let ratelimit_limit = headers.get("x-ratelimit-limit").map(|x| x.to_owned());
         self.ratelimit_remaining = number_header(headers.get("x-ratelimit-remaining"))?;
         self.ratelimit_reset = number_header(headers.get("x-ratelimit-reset"))?;
@@ -78,18 +83,27 @@ impl GithubEndpointWatcher {
             self.etag = etag;
             self.last_modified_at = last_modified_at;
             let poll_interval_parsed: u64 = poll_interval.unwrap_or_else(|| {
-                info!("No poll interval returned, defaulting to 5 minute polling.");
-                300
+                let fallback_interval = self.previous_poll_interval.unwrap_or(300);
+                info!(
+                    "No poll interval returned, defaulting to {} second polling.",
+                    fallback_interval
+                );
+                fallback_interval
             });
             self.next_poll_allowed = request_started_at + poll_interval_parsed;
             return Ok(None);
         } else {
             let body = response.json::<serde_json::Value>().await?;
+
             self.etag = etag;
             self.last_modified_at = last_modified_at;
             let poll_interval_parsed: u64 = poll_interval.unwrap_or_else(|| {
-                info!("No poll interval returned, defaulting to 5 minute polling.");
-                300
+                let fallback_interval = self.previous_poll_interval.unwrap_or(300);
+                info!(
+                    "No poll interval returned, defaulting to {} second polling.",
+                    fallback_interval
+                );
+                fallback_interval
             });
             self.next_poll_allowed = request_started_at + poll_interval_parsed;