Extract job documentation URL from logs

src/bin/server/worker.rs

@@ -295,6 +295,10 @@ impl Worker {
             Some(job_name) => format!("The job **`{}`**", job_name),
             None => "A job".to_owned(),
         };
+        let trailer = match log_variables.doc_url {
+            Some(url) => format!("\nFor more information how to resolve CI failures of this job, visit this [link]({url})."),
+            None => "".to_string(),
+        };
 
         let log_url = job.log_url().unwrap_or_else(|| "unknown".into());
         self.github.post_comment(repo, pr, &format!(r#"
@@ -307,7 +311,7 @@ impl Worker {
 ```
 
 </details>
-        "#, opening = opening, html_url = job.html_url(), log_url = log_url, log = extracted))?;
+{trailer}"#, opening = opening, html_url = job.html_url(), log_url = log_url, log = extracted, trailer = trailer))?;
 
         info!("marked build {} as recently notified", build_id);
         self.recently_notified.store(build_id);

src/log_variables.rs

@@ -4,17 +4,22 @@ const SEPARATOR: u8 = b'=';
 
 const JOB_NAME_VARIABLE: &str = "CI_JOB_NAME";
 const PR_NUMBER_VARIABLE: &str = "CI_PR_NUMBER";
+/// URL pointing to a documentation page about the job.
+/// Added in https://github.com/rust-lang/rust/pull/136911.
+const JOB_DOC_URL: &str = "CI_JOB_DOC_URL";
 
 pub struct LogVariables<'a> {
     pub job_name: Option<&'a str>,
     pub pr_number: Option<&'a str>,
+    pub doc_url: Option<&'a str>,
 }
 
 impl<'a> LogVariables<'a> {
     pub fn extract<I: crate::index::IndexData>(lines: &'a [I]) -> Self {
         let mut result = LogVariables {
             job_name: None,
             pr_number: None,
+            doc_url: None,
         };
 
         for line in lines {
@@ -26,9 +31,12 @@ impl<'a> LogVariables<'a> {
             if result.pr_number.is_none() {
                 result.pr_number = extract_variable(sanitized, PR_NUMBER_VARIABLE);
             }
+            if result.doc_url.is_none() {
+                result.doc_url = extract_variable(sanitized, JOB_DOC_URL);
+            }
 
             // Early exit if everything was found
-            if result.job_name.is_some() && result.pr_number.is_some() {
+            if result.job_name.is_some() && result.pr_number.is_some() && result.doc_url.is_some() {
                 break;
             }
         }
@@ -72,10 +80,16 @@ mod tests {
             Sanitized("baz"),
             Sanitized("[CI_PR_NUMBER=123]"),
             Sanitized("quux"),
+            Sanitized("[CI_JOB_DOC_URL=https://github.com/rust-lang/rust/job1]"),
+            Sanitized("foobar"),
         ];
 
         let extracted = LogVariables::extract(LOG);
         assert_eq!(Some("test-job"), extracted.job_name);
         assert_eq!(Some("123"), extracted.pr_number);
+        assert_eq!(
+            Some("https://github.com/rust-lang/rust/job1"),
+            extracted.doc_url
+        );
     }
 }