add builtin docker-hub support

Cargo.lock

@@ -566,6 +566,15 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "num_threads"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2819ce041d2ee131036f4fc9d6ae7ae125a3a40e97ba64d04fe799ad9dabbb44"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "object"
 version = "0.29.0"
@@ -727,6 +736,7 @@ dependencies = [
  "rss",
  "serde",
  "serde_json",
+ "time",
  "tokio",
  "toml",
 ]
@@ -892,6 +902,18 @@ dependencies = [
  "once_cell",
 ]
 
+[[package]]
+name = "time"
+version = "0.3.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "72c91f41dcb2f096c05f0873d667dceec1087ce5bcf984ec8ffb19acddbb3217"
+dependencies = [
+ "itoa",
+ "libc",
+ "num_threads",
+ "serde",
+]
+
 [[package]]
 name = "tinyvec"
 version = "1.6.0"

Cargo.toml

@@ -14,3 +14,4 @@ toml = "0.5.9"
 color-eyre = "0.6.2"
 env_logger = "0.9.0"
 log = "0.4.17"
+time = { version = "0.3.11", features = ["serde", "serde-well-known"] }

README.md

@@ -21,4 +21,9 @@ feed = "https://example.com/feed2.xml"
 hook = "https://hook.example.com/hook2/call"
 headers = { authorization = "...." }
 body = { event_type = "build" }
+
+# trigger on docker hub updates instead of rss feed update
+[[feed]]
+feed = "docker-hub://matrixdotorg/synapse"
+hook = "https://hook.example.com/hook2/call"
 ```

src/hub.rs

@@ -0,0 +1,42 @@
+use color_eyre::eyre::WrapErr;
+use color_eyre::{eyre::ensure, Result};
+use reqwest::Client;
+use serde::Deserialize;
+use time::OffsetDateTime;
+
+pub async fn tags(client: &Client, user: &str, repo: &str) -> Result<Vec<HubTag>> {
+    let result = client
+        .get(format!(
+            "https://hub.docker.com/v2/repositories/{}/{}/tags",
+            user, repo
+        ))
+        .send()
+        .await
+        .wrap_err("error with sending docker hub request")?;
+    ensure!(
+        !result.status().is_client_error(),
+        "error with sending docker hub request"
+    );
+    ensure!(
+        !result.status().is_server_error(),
+        "docker hub request returned an error"
+    );
+    Ok(result
+        .json::<HubTagResponse>()
+        .await
+        .wrap_err("failed to parse hub response")?
+        .results)
+}
+
+#[derive(Debug, Deserialize)]
+pub struct HubTagResponse {
+    results: Vec<HubTag>,
+}
+
+#[derive(Debug, Deserialize)]
+pub struct HubTag {
+    pub id: u64,
+    #[serde(with = "time::serde::rfc3339")]
+    pub last_updated: OffsetDateTime,
+    pub name: String,
+}

src/main.rs

@@ -1,4 +1,5 @@
 mod config;
+mod hub;
 
 use crate::config::{Config, FeedConfig};
 use color_eyre::{
@@ -107,6 +108,25 @@ impl FeedFetcher {
     }
 
     async fn get_feed_key(&self, feed: &str) -> Result<u64> {
+        if let Some(hub) = feed.strip_prefix("docker-hub://") {
+            if let Some((user, repo)) = hub.split_once('/') {
+                let tags = hub::tags(&self.client, user, repo).await?;
+                let mut hasher = DefaultHasher::new();
+                for tag in tags {
+                    tag.id.hash(&mut hasher);
+                    tag.last_updated.hash(&mut hasher);
+                }
+
+                Ok(hasher.finish())
+            } else {
+                return Err(eyre!("Invalid hub format {}", feed))
+            }
+        } else {
+            self.get_rss_feed_key(feed).await
+        }
+    }
+
+    async fn get_rss_feed_key(&self, feed: &str) -> Result<u64> {
         let content = self
             .client
             .get(feed)