From 9e5093dbca19b91d76d5fea739722a53d49bacbb Mon Sep 17 00:00:00 2001 From: Jake Utley Date: Mon, 9 Sep 2019 16:31:21 -0700 Subject: [PATCH] Add some comments about failed history logic. --- history.go | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/history.go b/history.go index 0cec9cddf..c4977d0ed 100644 --- a/history.go +++ b/history.go @@ -25,11 +25,14 @@ type result struct { success bool } +// resultHistory contains two history slices: `results` contains most recent `maxResults` results. +// After they expire out of `results`, failures will be saved in `preservedFailedResults`. This +// ensures that we are always able to see debug information about recent failures. type resultHistory struct { mu sync.Mutex nextId int64 results []*result - preservedFailedResults []*result + preservedFailedResults []*result maxResults uint } @@ -49,6 +52,8 @@ func (rh *resultHistory) Add(moduleName, target, debugOutput string, success boo rh.results = append(rh.results, r) if uint(len(rh.results)) > rh.maxResults { + // If we are about to remove a failure, add it to the failed result history, then + // remove the oldest failed result, if needed. if !rh.results[0].success { rh.preservedFailedResults = append(rh.preservedFailedResults, rh.results[0]) if uint(len(rh.preservedFailedResults)) > rh.maxResults { @@ -68,6 +73,7 @@ func (rh *resultHistory) List() []*result { rh.mu.Lock() defer rh.mu.Unlock() + // Results in each slice are disjoint. We can simply concatenate the results. return append(rh.preservedFailedResults[:], rh.results...) }