From ae959219668523166c4133269657df8f35c97e49 Mon Sep 17 00:00:00 2001
From: Tyler Hallada <tyler@hallada.net>
Date: Sat, 15 Jul 2023 01:30:45 -0400
Subject: [PATCH] Update feed last_crawl_error & crawl_interval_minutes

---
 src/actors/feed_crawler.rs | 43 ++++++++++++++++++++++++++++++--------
 src/models/feed.rs         | 17 ++++++++++++++-
 2 files changed, 50 insertions(+), 10 deletions(-)

diff --git a/src/actors/feed_crawler.rs b/src/actors/feed_crawler.rs
index 4a03bdb..d4b1158 100644
--- a/src/actors/feed_crawler.rs
+++ b/src/actors/feed_crawler.rs
@@ -1,19 +1,20 @@
+use std::cmp::Ordering;
 use std::fmt::{self, Display, Formatter};
 
-use chrono::Utc;
+use chrono::{Duration, Utc};
 use feed_rs::parser;
 use reqwest::Client;
 use sqlx::PgPool;
 use tokio::sync::{broadcast, mpsc};
 use tracing::log::warn;
-use tracing::{info, info_span, instrument};
+use tracing::{error, info, info_span, instrument};
 use url::Url;
 use uuid::Uuid;
 
 use crate::actors::entry_crawler::EntryCrawlerHandle;
 use crate::domain_locks::DomainLocks;
 use crate::models::entry::{CreateEntry, Entry};
-use crate::models::feed::Feed;
+use crate::models::feed::{Feed, MAX_CRAWL_INTERVAL_MINUTES, MIN_CRAWL_INTERVAL_MINUTES};
 use crate::uuid::Base62Uuid;
 
 /// The `FeedCrawler` actor fetches a feed url, parses it, and saves it to the database.
@@ -88,8 +89,8 @@ impl FeedCrawler {
             .await
             .map_err(|_| FeedCrawlerError::GetFeedError(Base62Uuid::from(feed_id)))?;
         info!("got feed from db");
-        let url = Url::parse(&feed.url)
-            .map_err(|_| FeedCrawlerError::InvalidUrl(feed.url.clone()))?;
+        let url =
+            Url::parse(&feed.url).map_err(|_| FeedCrawlerError::InvalidUrl(feed.url.clone()))?;
         let domain = url
             .domain()
             .ok_or(FeedCrawlerError::InvalidUrl(feed.url.clone()))?;
@@ -113,12 +114,32 @@ impl FeedCrawler {
         feed.url = url.to_string();
         feed.feed_type = parsed_feed.feed_type.into();
         feed.last_crawled_at = Some(Utc::now());
+        feed.last_crawl_error = None;
         if let Some(title) = parsed_feed.title {
             feed.title = Some(title.content);
         }
         if let Some(description) = parsed_feed.description {
             feed.description = Some(description.content);
         }
+        let last_entry_published_at = parsed_feed.entries.iter().filter_map(|e| e.published).max();
+        if let Some(prev_last_entry_published_at) = feed.last_entry_published_at {
+            if let Some(published_at) = last_entry_published_at {
+                let time_since_last_entry = published_at - prev_last_entry_published_at;
+                match time_since_last_entry
+                    .cmp(&Duration::minutes(feed.crawl_interval_minutes.into()))
+                {
+                    Ordering::Greater => {
+                        feed.crawl_interval_minutes =
+                            i32::max(feed.crawl_interval_minutes * 2, MAX_CRAWL_INTERVAL_MINUTES);
+                    },
+                    Ordering::Less => {
+                        feed.crawl_interval_minutes =
+                            i32::max(feed.crawl_interval_minutes / 2, MIN_CRAWL_INTERVAL_MINUTES);
+                    },
+                    Ordering::Equal => {},
+                }
+            }
+        }
         let feed = feed
             .save(&self.pool)
             .await
@@ -173,6 +194,13 @@ impl FeedCrawler {
                 respond_to,
             } => {
                 let result = self.crawl_feed(feed_id).await;
+                if let Err(error) = &result {
+                    match Feed::update_crawl_error(&self.pool, feed_id, format!("{}", error)).await {
+                        Ok(_) => info!("updated feed last_crawl_error"),
+                        Err(e) => error!("failed to update feed last_crawl_error: {}", e),
+                    }
+                }
+                
                 // ignore the result since the initiator may have cancelled waiting for the
                 // response, and that is ok
                 let _ = respond_to.send(FeedCrawlerHandleMessage::Feed(result));
@@ -227,10 +255,7 @@ impl FeedCrawlerHandle {
     /// Sends a `FeedCrawlerMessage::Crawl` message to the running `FeedCrawler` actor.
     ///
     /// Listen to the result of the crawl via the returned `broadcast::Receiver`.
-    pub async fn crawl(
-        &self,
-        feed_id: Uuid,
-    ) -> broadcast::Receiver<FeedCrawlerHandleMessage> {
+    pub async fn crawl(&self, feed_id: Uuid) -> broadcast::Receiver<FeedCrawlerHandleMessage> {
         let (sender, receiver) = broadcast::channel(8);
         let msg = FeedCrawlerMessage::Crawl {
             feed_id,
diff --git a/src/models/feed.rs b/src/models/feed.rs
index ab4f77a..909c974 100644
--- a/src/models/feed.rs
+++ b/src/models/feed.rs
@@ -2,7 +2,7 @@ use std::str::FromStr;
 
 use chrono::{DateTime, Utc};
 use serde::{Deserialize, Serialize};
-use sqlx::{FromRow, PgPool};
+use sqlx::{FromRow, PgPool, postgres::PgQueryResult};
 use uuid::Uuid;
 use validator::Validate;
 
@@ -47,6 +47,9 @@ impl From<feed_rs::model::FeedType> for FeedType {
     }
 }
 
+pub const MIN_CRAWL_INTERVAL_MINUTES: i32 = 1;
+pub const MAX_CRAWL_INTERVAL_MINUTES: i32 = 5040;
+
 #[derive(Debug, Serialize, Deserialize, Clone, FromRow)]
 pub struct Feed {
     pub feed_id: Uuid,
@@ -276,6 +279,18 @@ impl Feed {
         Ok(())
     }
 
+    pub async fn update_crawl_error(pool: &PgPool, feed_id: Uuid, last_crawl_error: String) -> Result<PgQueryResult> {
+        Ok(sqlx::query!(
+            r#"update feed set
+                last_crawl_error = $2
+            where feed_id = $1"#,
+            feed_id,
+            last_crawl_error,
+        )
+        .execute(pool)
+        .await?)
+    }
+
     pub async fn save(&self, pool: &PgPool) -> Result<Feed> {
         Ok(sqlx::query_as!(
             Feed,