/
shell.go
166 lines (139 loc) · 3.05 KB
/
shell.go
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package shell
import (
"context"
"database/sql"
"fmt"
"strings"
"github.com/canonical/go-dqlite/client"
"github.com/canonical/go-dqlite/driver"
)
// Shell can be used to implement interactive prompts for inspecting a dqlite
// database.
type Shell struct {
store client.NodeStore
dial client.DialFunc
db *sql.DB
}
// New creates a new Shell connected to the given database.
func New(database string, store client.NodeStore, options ...Option) (*Shell, error) {
o := defaultOptions()
for _, option := range options {
option(o)
}
driver, err := driver.New(store, driver.WithDialFunc(o.Dial))
if err != nil {
return nil, err
}
sql.Register(o.DriverName, driver)
db, err := sql.Open(o.DriverName, database)
if err != nil {
return nil, err
}
shell := &Shell{
store: store,
dial: o.Dial,
db: db,
}
return shell, nil
}
// Process a single input line.
func (s *Shell) Process(ctx context.Context, line string) (string, error) {
switch line {
case ".cluster":
return s.processCluster(ctx, line)
case ".leader":
return s.processLeader(ctx, line)
}
if strings.HasPrefix(line, "SELECT") {
return s.processSelect(ctx, line)
} else {
return "", s.processExec(ctx, line)
}
}
func (s *Shell) processCluster(ctx context.Context, line string) (string, error) {
cli, err := client.FindLeader(ctx, s.store, client.WithDialFunc(s.dial))
if err != nil {
return "", err
}
cluster, err := cli.Cluster(ctx)
if err != nil {
return "", err
}
result := ""
for i, server := range cluster {
if i > 0 {
result += "\n"
}
result += fmt.Sprintf("%x|%s|%s", server.ID, server.Address, server.Role)
}
return result, nil
}
func (s *Shell) processLeader(ctx context.Context, line string) (string, error) {
cli, err := client.FindLeader(ctx, s.store, client.WithDialFunc(s.dial))
if err != nil {
return "", err
}
leader, err := cli.Leader(ctx)
if err != nil {
return "", err
}
if leader == nil {
return "", nil
}
return leader.Address, nil
}
func (s *Shell) processSelect(ctx context.Context, line string) (string, error) {
tx, err := s.db.BeginTx(ctx, nil)
if err != nil {
return "", err
}
rows, err := tx.Query(line)
if err != nil {
return "", err
}
defer rows.Close()
columns, err := rows.Columns()
if err != nil {
return "", err
}
n := len(columns)
result := ""
for rows.Next() {
row := make([]interface{}, n)
rowPointers := make([]interface{}, n)
for i := range row {
rowPointers[i] = &row[i]
}
if err := rows.Scan(rowPointers...); err != nil {
return "", err
}
for i, column := range row {
s := fmt.Sprintf("%v", column)
if i == 0 {
result = s
} else {
result += "|" + s
}
}
}
if err := rows.Err(); err != nil {
return "", err
}
if err := tx.Commit(); err != nil {
return "", err
}
return result, nil
}
func (s *Shell) processExec(ctx context.Context, line string) error {
tx, err := s.db.BeginTx(ctx, nil)
if err != nil {
return err
}
if _, err := tx.Exec(line); err != nil {
return err
}
if err := tx.Commit(); err != nil {
return err
}
return nil
}