Skip to content

[extension/dbstorage] Add DB Transactions to dbstorage.Batch() method #37805

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
Show file tree
Hide file tree
Changes from 1 commit
Commits
File filter

Filter by extension

Filter by extension


Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
27 changes: 27 additions & 0 deletions .chloggen/feat_dbstorage-transaction-support.yaml
Original file line number Diff line number Diff line change
@@ -0,0 +1,27 @@
# Use this changelog template to create an entry for release notes.

# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
change_type: enhancement

# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
component: dbstorageextension

# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
note: Add DB Transactions to dbstorage.Batch() method as it is expected by Storage API

# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
issues: [37805]

# (Optional) One or more lines of additional information to render under the primary note.
# These lines will be padded with 2 spaces and then inserted directly into the document.
# Use pipe (|) for multiline entries.
subtext:

# If your change doesn't affect end users or the exported elements of any package,
# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
# Optional: The change log or logs in which this entry should be included.
# e.g. '[user]' or '[user, api]'
# Include 'user' if the change is relevant to end users.
# Include 'api' if there is a change to a library API.
# Default: '[user]'
change_logs: [api]
77 changes: 53 additions & 24 deletions extension/storage/dbstorage/client.go
Original file line number Diff line number Diff line change
Expand Up @@ -33,7 +33,7 @@ type dbStorageClient struct {

func newClient(ctx context.Context, driverName string, db *sql.DB, tableName string) (*dbStorageClient, error) {
createTableSQL := createTable
if driverName == "sqlite" {
if driverName == driverSqlite {
createTableSQL = createTableSqlite
}
var err error
Expand All @@ -59,45 +59,37 @@ func newClient(ctx context.Context, driverName string, db *sql.DB, tableName str

// Get will retrieve data from storage that corresponds to the specified key
func (c *dbStorageClient) Get(ctx context.Context, key string) ([]byte, error) {
rows, err := c.getQuery.QueryContext(ctx, key)
if err != nil {
return nil, err
}
if !rows.Next() {
return nil, nil
}
var result []byte
err = rows.Scan(&result)
if err != nil {
return result, err
}
err = rows.Close()
return result, err
return c.get(ctx, key, nil)
}

// Set will store data. The data can be retrieved using the same key
func (c *dbStorageClient) Set(ctx context.Context, key string, value []byte) error {
_, err := c.setQuery.ExecContext(ctx, key, value, value)
return err
return c.set(ctx, key, value, nil)
}

// Delete will delete data associated with the specified key
func (c *dbStorageClient) Delete(ctx context.Context, key string) error {
_, err := c.deleteQuery.ExecContext(ctx, key)
return err
return c.delete(ctx, key, nil)
}

// Batch executes the specified operations in order. Get operation results are updated in place
func (c *dbStorageClient) Batch(ctx context.Context, ops ...*storage.Operation) error {
var err error
// Start a new transaction
tx, err := c.db.BeginTx(ctx, nil)
if err != nil {
return err
}
//nolint:errcheck
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

do we not want to do something on error here?

Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Agreed, I'd at least log the error.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Added logging here
Unfortunately there was no logger instance in this object, so have to inject it, I believe it might be useful in this object for future improvements

defer tx.Rollback()
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This might be confusing for other developers. We commit the tx on return and a rollback call is also made due to this defer.
There are two scenarios:

  1. when any error is encoutered
  2. when no error is encountered

First scenario is straightforward. We return the error and a rollback is called.

For the second scenario, we commit the transaction and then rollback is called due to the defer. The rollback call in this scenario is a no-op because tx is already committed.

Can we add a comment here to mention this nuance?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Added few comments to clarify commit/rollback flow, as well as for tx.Rollback() error handling


for _, op := range ops {
switch op.Type {
case storage.Get:
op.Value, err = c.Get(ctx, op.Key)
op.Value, err = c.get(ctx, op.Key, tx)
case storage.Set:
err = c.Set(ctx, op.Key, op.Value)
err = c.set(ctx, op.Key, op.Value, tx)
case storage.Delete:
err = c.Delete(ctx, op.Key)
err = c.delete(ctx, op.Key, tx)
default:
return errors.New("wrong operation type")
}
Expand All @@ -106,7 +98,8 @@ func (c *dbStorageClient) Batch(ctx context.Context, ops ...*storage.Operation)
return err
}
}
return err

return tx.Commit()
}

// Close will close the database
Expand All @@ -119,3 +112,39 @@ func (c *dbStorageClient) Close(_ context.Context) error {
}
return c.getQuery.Close()
}

func (c *dbStorageClient) get(ctx context.Context, key string, tx *sql.Tx) ([]byte, error) {
rows, err := c.wrapTx(c.getQuery, tx).QueryContext(ctx, key)
if err != nil {
return nil, err
}

if !rows.Next() {
return nil, nil
}

var result []byte
if err := rows.Scan(&result); err != nil {
return result, err
}

return result, rows.Close()
}

func (c *dbStorageClient) set(ctx context.Context, key string, value []byte, tx *sql.Tx) error {
_, err := c.wrapTx(c.setQuery, tx).ExecContext(ctx, key, value, value)
return err
}

func (c *dbStorageClient) delete(ctx context.Context, key string, tx *sql.Tx) error {
_, err := c.wrapTx(c.deleteQuery, tx).ExecContext(ctx, key)
return err
}

func (c *dbStorageClient) wrapTx(stmt *sql.Stmt, tx *sql.Tx) *sql.Stmt {
if tx != nil {
return tx.Stmt(stmt)
}

return stmt
}
Loading