Files
relspecgo/pkg/readers/mysql/reader.go
T

246 lines
7.3 KiB
Go

package mysql
import (
"context"
"database/sql"
"fmt"
"strings"
_ "github.com/go-sql-driver/mysql"
"git.warky.dev/wdevs/relspecgo/pkg/mariadb"
"git.warky.dev/wdevs/relspecgo/pkg/models"
"git.warky.dev/wdevs/relspecgo/pkg/readers"
)
type Reader struct {
options *readers.ReaderOptions
db *sql.DB
ctx context.Context
}
func NewReader(options *readers.ReaderOptions) *Reader {
return &Reader{options: options, ctx: context.Background()}
}
func (r *Reader) ReadDatabase() (*models.Database, error) {
if r.options == nil || r.options.ConnectionString == "" {
return nil, fmt.Errorf("connection string is required")
}
if err := r.connect(); err != nil {
return nil, fmt.Errorf("failed to connect: %w", err)
}
defer r.close()
var name, version string
if err := r.db.QueryRowContext(r.ctx, "SELECT DATABASE()").Scan(&name); err != nil {
return nil, fmt.Errorf("failed to get database name: %w", err)
}
_ = r.db.QueryRowContext(r.ctx, "SELECT VERSION()").Scan(&version)
db := models.InitDatabase(name)
db.DatabaseType, db.SourceFormat, db.DatabaseVersion = models.MySQLDatabaseType, "mysql", version
schemas, err := r.querySchemas(name)
if err != nil {
return nil, fmt.Errorf("failed to query schemas: %w", err)
}
for _, schema := range schemas {
tables, err := r.queryTables(schema.Name)
if err != nil {
return nil, err
}
schema.Tables = tables
for _, table := range tables {
table.Columns, err = r.queryColumns(schema.Name, table.Name)
if err != nil {
return nil, err
}
table.Constraints, err = r.queryConstraints(schema.Name, table.Name)
if err != nil {
return nil, err
}
table.Indexes, err = r.queryIndexes(schema.Name, table.Name)
if err != nil {
return nil, err
}
table.RefSchema = schema
for _, c := range table.Constraints {
if c.Type == models.ForeignKeyConstraint {
r.deriveRelationship(table, c)
}
}
}
schema.RefDatabase = db
db.Schemas = append(db.Schemas, schema)
}
return db, nil
}
func (r *Reader) ReadSchema() (*models.Schema, error) {
db, err := r.ReadDatabase()
if err != nil {
return nil, err
}
if len(db.Schemas) == 0 {
return nil, fmt.Errorf("no schemas found in database")
}
return db.Schemas[0], nil
}
func (r *Reader) ReadTable() (*models.Table, error) {
s, err := r.ReadSchema()
if err != nil {
return nil, err
}
if len(s.Tables) == 0 {
return nil, fmt.Errorf("no tables found in schema")
}
return s.Tables[0], nil
}
func (r *Reader) connect() error {
db, err := sql.Open("mysql", r.options.ConnectionString)
if err != nil {
return err
}
if err = db.PingContext(r.ctx); err != nil {
db.Close()
return err
}
r.db = db
return nil
}
func (r *Reader) close() {
if r.db != nil {
_ = r.db.Close()
}
}
func (r *Reader) mapDataType(t string) string { return mariadb.ConvertMariaDBToCanonical(t) }
func (r *Reader) querySchemas(current string) ([]*models.Schema, error) {
rows, err := r.db.QueryContext(r.ctx, "SELECT SCHEMA_NAME FROM information_schema.SCHEMATA WHERE SCHEMA_NAME = ?", current)
if err != nil {
return nil, err
}
defer rows.Close()
var out []*models.Schema
for rows.Next() {
var n string
if err := rows.Scan(&n); err != nil {
return nil, err
}
out = append(out, models.InitSchema(n))
}
return out, rows.Err()
}
func (r *Reader) queryTables(schema string) ([]*models.Table, error) {
rows, err := r.db.QueryContext(r.ctx, "SELECT TABLE_NAME FROM information_schema.TABLES WHERE TABLE_SCHEMA = ? AND TABLE_TYPE = 'BASE TABLE' ORDER BY TABLE_NAME", schema)
if err != nil {
return nil, err
}
defer rows.Close()
var out []*models.Table
for rows.Next() {
var n string
if err := rows.Scan(&n); err != nil {
return nil, err
}
out = append(out, models.InitTable(n, schema))
}
return out, rows.Err()
}
func (r *Reader) queryColumns(schema, table string) (map[string]*models.Column, error) {
rows, err := r.db.QueryContext(r.ctx, `SELECT COLUMN_NAME, COLUMN_TYPE, IS_NULLABLE, COLUMN_DEFAULT, ORDINAL_POSITION, EXTRA, COLUMN_COMMENT FROM information_schema.COLUMNS WHERE TABLE_SCHEMA = ? AND TABLE_NAME = ? ORDER BY ORDINAL_POSITION`, schema, table)
if err != nil {
return nil, err
}
defer rows.Close()
out := map[string]*models.Column{}
for rows.Next() {
var name, typ, nullable, extra, comment string
var def sql.NullString
var pos int
if err := rows.Scan(&name, &typ, &nullable, &def, &pos, &extra, &comment); err != nil {
return nil, err
}
c := models.InitColumn(name, table, schema)
c.Type = r.mapDataType(typ)
c.NotNull = strings.EqualFold(nullable, "NO")
c.Sequence = uint(pos)
c.Comment = comment
if def.Valid {
c.Default = def.String
}
c.AutoIncrement = strings.Contains(strings.ToLower(extra), "auto_increment")
out[name] = c
}
return out, rows.Err()
}
func (r *Reader) queryConstraints(schema, table string) (map[string]*models.Constraint, error) {
rows, err := r.db.QueryContext(r.ctx, `SELECT CONSTRAINT_NAME, CONSTRAINT_TYPE, COLUMN_NAME, REFERENCED_TABLE_SCHEMA, REFERENCED_TABLE_NAME, REFERENCED_COLUMN_NAME, ORDINAL_POSITION FROM information_schema.KEY_COLUMN_USAGE k JOIN information_schema.TABLE_CONSTRAINTS t USING (CONSTRAINT_SCHEMA, TABLE_NAME, CONSTRAINT_NAME) WHERE k.TABLE_SCHEMA=? AND k.TABLE_NAME=? ORDER BY CONSTRAINT_NAME, ORDINAL_POSITION`, schema, table)
if err != nil {
return nil, err
}
defer rows.Close()
out := map[string]*models.Constraint{}
for rows.Next() {
var name, typ, col, rs, rt, rc string
var pos int
if err := rows.Scan(&name, &typ, &col, &rs, &rt, &rc, &pos); err != nil {
return nil, err
}
c := out[name]
if c == nil {
ct := models.UniqueConstraint
if typ == "PRIMARY KEY" {
ct = models.PrimaryKeyConstraint
}
if typ == "FOREIGN KEY" {
ct = models.ForeignKeyConstraint
}
c = models.InitConstraint(name, ct)
c.Schema = schema
c.Table = table
c.ReferencedSchema = rs
c.ReferencedTable = rt
out[name] = c
}
c.Columns = append(c.Columns, col)
if rc != "" {
c.ReferencedColumns = append(c.ReferencedColumns, rc)
}
}
return out, rows.Err()
}
func (r *Reader) queryIndexes(schema, table string) (map[string]*models.Index, error) {
rows, err := r.db.QueryContext(r.ctx, `SELECT INDEX_NAME, NON_UNIQUE, COLUMN_NAME, SEQ_IN_INDEX, INDEX_TYPE FROM information_schema.STATISTICS WHERE TABLE_SCHEMA=? AND TABLE_NAME=? AND INDEX_NAME <> 'PRIMARY' ORDER BY INDEX_NAME, SEQ_IN_INDEX`, schema, table)
if err != nil {
return nil, err
}
defer rows.Close()
out := map[string]*models.Index{}
for rows.Next() {
var name, col, typ string
var non, seq int
if err := rows.Scan(&name, &non, &col, &seq, &typ); err != nil {
return nil, err
}
i := out[name]
if i == nil {
i = models.InitIndex(name, table, schema)
i.Unique = non == 0
i.Type = strings.ToLower(typ)
out[name] = i
}
i.Columns = append(i.Columns, col)
}
return out, rows.Err()
}
func (r *Reader) deriveRelationship(t *models.Table, c *models.Constraint) {
n := fmt.Sprintf("%s_to_%s", t.Name, c.ReferencedTable)
rel := models.InitRelationship(n, models.OneToMany)
rel.FromTable = t.Name
rel.FromSchema = t.Schema
rel.FromColumns = append([]string(nil), c.Columns...)
rel.ToTable = c.ReferencedTable
rel.ToSchema = c.ReferencedSchema
rel.ToColumns = append([]string(nil), c.ReferencedColumns...)
rel.ForeignKey = c.Name
t.Relationships[n] = rel
}