Enable token prefix masking

If the features passed by the Gitlab server indicate that there are
token prefixes that should be masked, this adds those prefixes to the
Masker. This is fully transparent to users of this crate; the correct
thing will happen provided they correctly identify which artifacts
they believe should be masked. The trace will always be masked
correctly.

Author: eds-collabora

gitlab-runner/src/run.rs

@@ -1,5 +1,5 @@
 use bytes::Bytes;
-use masker::Masker;
+use masker::{Masker, MatchData};
 use std::future::Future;
 use std::path::PathBuf;
 use std::sync::Arc;
@@ -17,6 +17,8 @@ use crate::CancellableJobHandler;
 use crate::{JobResult, Phase};
 
 const GITLAB_MASK: &str = "[MASKED]";
+const GITLAB_TOKEN_SUFFIX_CHARS: &str =
+    "-.0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz=";
 
 async fn run<F, J, Ret>(
     job: Job,
@@ -195,7 +197,22 @@ impl Run {
             .filter(|(_, v)| v.masked)
             .map(|(_, v)| v.value.as_str())
             .collect::<Vec<_>>();
-        let masker = Masker::new(&masked_variables, GITLAB_MASK);
+        let prefixes = self
+            .response
+            .features
+            .iter()
+            .flat_map(|x| x.token_mask_prefixes.iter())
+            // This matches the behaviour of the gitlab runner, which
+            // explicitly supports a maximum of 10 prefixes.
+            .take(10)
+            .map(|p| MatchData {
+                prefix: p.trim().as_bytes(),
+                suffix: GITLAB_TOKEN_SUFFIX_CHARS.as_bytes(),
+                mask_prefix: false,
+            })
+            .collect::<Vec<_>>();
+
+        let masker = Masker::new_with_match_data(&masked_variables, &prefixes, GITLAB_MASK);
 
         let job = Job::new(
             self.client.clone(),