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Revert index when error occur on issue/PR creation #21362

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Revert index when error occur on issue/PR creation #21362

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a9da2ec
Revert index when error occur on issue/PR creation
Oct 6, 2022
8e8f781
Remove testing code
Oct 6, 2022
13cf733
Merge branch 'main' into gracefully-revert-idx
zeripath Oct 6, 2022
0bb3bf5
Merge branch 'main' into gracefully-revert-idx
zeripath Oct 8, 2022
cce1089
Merge branch 'main' into gracefully-revert-idx
Oct 10, 2022
9951025
Merge branch 'main' into gracefully-revert-idx
Oct 11, 2022
7ea3b9c
Merge branch 'main' into gracefully-revert-idx
Oct 14, 2022
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30 changes: 30 additions & 0 deletions models/db/index.go
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Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,36 @@ func UpsertResourceIndex(ctx context.Context, tableName string, groupID int64) (
return err
}

// UpsertDecrResourceIndex the function will not return until it acquires the lock or receives an error.
func UpsertDecrResourceIndex(ctx context.Context, tableName string, groupID, prevIdx int64) (err error) {
// An atomic UPSERT operation (INSERT/UPDATE) is the only operation
// that ensures that the key is actually locked.
// It will try to decrease the max_index, however if max_index is already higher,
// then don't try to decrease the index value.
switch {
case setting.Database.UseSQLite3 || setting.Database.UsePostgreSQL:
_, err = Exec(ctx, fmt.Sprintf("INSERT INTO %s (group_id, max_index) "+
"VALUES (?,1) ON CONFLICT (group_id) DO UPDATE SET max_index = CASE WHEN %s.max_index = %d THEN %s.max_index-1 ELSE %s.max_index END",
tableName, tableName, prevIdx, tableName, tableName), groupID)
case setting.Database.UseMySQL:
_, err = Exec(ctx, fmt.Sprintf("INSERT INTO %s (group_id, max_index) "+
"VALUES (?,1) ON DUPLICATE KEY UPDATE max_index = CASE WHEN max_index = %d THEN max_index-1 ELSE max_index END", tableName, prevIdx),
groupID)
case setting.Database.UseMSSQL:
// https://weblogs.sqlteam.com/dang/2009/01/31/upsert-race-condition-with-merge/
_, err = Exec(ctx, fmt.Sprintf("MERGE %s WITH (HOLDLOCK) as target "+
"USING (SELECT ? AS group_id) AS src "+
"ON src.group_id = target.group_id "+
"WHEN MATCHED THEN UPDATE SET target.max_index = CASE WHEN target.max_index = %d THEN target.max_index-1 ELSE target.max_index END"+
"WHEN NOT MATCHED THEN INSERT (group_id, max_index) "+
"VALUES (src.group_id, 1);", tableName, prevIdx),
groupID)
default:
return fmt.Errorf("database type not supported")
}
return err
}

var (
// ErrResouceOutdated represents an error when request resource outdated
ErrResouceOutdated = errors.New("resource outdated")
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19 changes: 19 additions & 0 deletions models/issues/issue.go
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Expand Up @@ -1077,19 +1077,38 @@ func NewIssue(repo *repo_model.Repository, issue *Issue, labelIDs []int64, uuids
}
defer committer.Close()

// onFail will try to gracefully revert the update in the resource index.
onFail := func() error {
// Close commiter.
committer.Close()
// Try to revert the increase in resource index.
if err := db.UpsertDecrResourceIndex(db.DefaultContext, "issue_index", repo.ID, idx); err != nil {
return fmt.Errorf("UpsertDecrResourceIndex: %v", err)
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Suggested change
return fmt.Errorf("UpsertDecrResourceIndex: %v", err)
return fmt.Errorf("UpsertDecrResourceIndex: %w", err)

}
return nil
}

if err = NewIssueWithIndex(ctx, issue.Poster, NewIssueOptions{
Repo: repo,
Issue: issue,
LabelIDs: labelIDs,
Attachments: uuids,
}); err != nil {
if err := onFail(); err != nil {
return fmt.Errorf("couldn't gracefully handle error: %v", err)
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Suggested change
return fmt.Errorf("couldn't gracefully handle error: %v", err)
return fmt.Errorf("couldn't gracefully handle error: %w", err)

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Is this a new code-style I haven't been aware of? Since when are we going to use the wrapping errors verb?

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Well, as I've learned: go seems to do some magic if you use %w instead of %v:
https://stackoverflow.com/a/61287626

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if we can wrap stuff my pr which tries to create a common hierarchy of errors will be a lot easier

}

if repo_model.IsErrUserDoesNotHaveAccessToRepo(err) || IsErrNewIssueInsert(err) {
return err
}
return fmt.Errorf("newIssue: %v", err)
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Wrap errors!

Suggested change
return fmt.Errorf("newIssue: %v", err)
return fmt.Errorf("newIssue: %w", err)

}

if err = committer.Commit(); err != nil {
if err := onFail(); err != nil {
return fmt.Errorf("couldn't gracefully handle error: %v", err)
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Suggested change
return fmt.Errorf("couldn't gracefully handle error: %v", err)
return fmt.Errorf("couldn't gracefully handle error: %w", err)

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And wrap the rest of them too if possible please

}

return fmt.Errorf("Commit: %v", err)
}

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22 changes: 22 additions & 0 deletions models/issues/pull.go
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Expand Up @@ -504,13 +504,27 @@ func NewPullRequest(outerCtx context.Context, repo *repo_model.Repository, issue
defer committer.Close()
ctx.WithContext(outerCtx)

// onFail will try to gracefully revert the update in the resource index.
onFail := func() error {
// Close commiter.
committer.Close()
// Try to revert the increase in resource index.
if err := db.UpsertDecrResourceIndex(outerCtx, "issue_index", repo.ID, idx); err != nil {
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I suspect that outerCtx isn't the correct thing here. In fact I'm certain it isn't.

db.DefaultContext is needed here.

return fmt.Errorf("UpsertDecrResourceIndex: %v", err)
}
return nil
}

if err = NewIssueWithIndex(ctx, issue.Poster, NewIssueOptions{
Repo: repo,
Issue: issue,
LabelIDs: labelIDs,
Attachments: uuids,
IsPull: true,
}); err != nil {
if err := onFail(); err != nil {
return fmt.Errorf("couldn't gracefully handle error: %v", err)
}
if repo_model.IsErrUserDoesNotHaveAccessToRepo(err) || IsErrNewIssueInsert(err) {
return err
}
Expand All @@ -521,10 +535,18 @@ func NewPullRequest(outerCtx context.Context, repo *repo_model.Repository, issue
pr.BaseRepo = repo
pr.IssueID = issue.ID
if err = db.Insert(ctx, pr); err != nil {
if err := onFail(); err != nil {
return fmt.Errorf("couldn't gracefully handle error: %v", err)
}

return fmt.Errorf("insert pull repo: %v", err)
}

if err = committer.Commit(); err != nil {
if err := onFail(); err != nil {
return fmt.Errorf("couldn't gracefully handle error: %v", err)
}

return fmt.Errorf("Commit: %v", err)
}

Expand Down