sq/drivers/json/import_jsona.go
Neil O'Toole 9c5836ef1c
: XLSX driver auto-detects header row ()
* xlsx driver now detects header row.
2023-07-08 09:21:27 -06:00

356 lines
7.9 KiB
Go

package json
import (
"bufio"
"context"
stdj "encoding/json"
"io"
"math"
"github.com/neilotoole/sq/libsq/core/record"
"github.com/neilotoole/sq/libsq/core/lg/lga"
"github.com/neilotoole/sq/libsq/core/lg/lgm"
"github.com/neilotoole/sq/libsq/core/lg"
"github.com/neilotoole/sq/libsq"
"github.com/neilotoole/sq/libsq/core/errz"
"github.com/neilotoole/sq/libsq/core/kind"
"github.com/neilotoole/sq/libsq/core/sqlmodel"
"github.com/neilotoole/sq/libsq/core/stringz"
"github.com/neilotoole/sq/libsq/driver"
"github.com/neilotoole/sq/libsq/source"
)
// DetectJSONA returns a source.DriverDetectFunc for TypeJSONA.
// Each line of input must be a valid JSON array.
func DetectJSONA(sampleSize int) source.DriverDetectFunc {
return func(ctx context.Context, openFn source.FileOpenFunc) (detected source.DriverType,
score float32, err error,
) {
log := lg.FromContext(ctx)
var r io.ReadCloser
r, err = openFn()
if err != nil {
return source.TypeNone, 0, errz.Err(err)
}
defer lg.WarnIfCloseError(log, lgm.CloseFileReader, r)
sc := bufio.NewScanner(r)
var validLines int
var line []byte
for sc.Scan() {
select {
case <-ctx.Done():
return source.TypeNone, 0, ctx.Err()
default:
}
if err = sc.Err(); err != nil {
return source.TypeNone, 0, errz.Err(err)
}
line = sc.Bytes()
if len(line) == 0 {
// Probably want to skip blank lines? Maybe
continue
}
// Each line of JSONA must open with left bracket
if line[0] != '[' {
return source.TypeNone, 0, nil
}
// If the line is JSONA, it should marshall into []any
var fields []any
err = stdj.Unmarshal(line, &fields)
if err != nil {
return source.TypeNone, 0, nil
}
// JSONA must consist only of values, not objects. Any object
// would get marshalled into a map[string]any, so
// we check for that.
for _, field := range fields {
if _, ok := field.(map[string]any); ok {
return source.TypeNone, 0, nil
}
}
validLines++
if validLines >= sampleSize {
break
}
}
if err = sc.Err(); err != nil {
return source.TypeNone, 0, errz.Err(err)
}
if validLines > 0 {
return TypeJSONA, 1.0, nil
}
return source.TypeNone, 0, nil
}
}
func importJSONA(ctx context.Context, job importJob) error {
log := lg.FromContext(ctx)
predictR, err := job.openFn()
if err != nil {
return errz.Err(err)
}
defer lg.WarnIfCloseError(log, lgm.CloseFileReader, predictR)
colKinds, readMungeFns, err := detectColKindsJSONA(ctx, predictR, job.sampleSize)
if err != nil {
return err
}
if len(colKinds) == 0 || len(readMungeFns) == 0 {
return errz.Errorf("import %s: number of fields is zero", TypeJSONA)
}
colNames := make([]string, len(colKinds))
for i := 0; i < len(colNames); i++ {
colNames[i] = stringz.GenerateAlphaColName(i, true)
}
// And now we need to create the dest table in destDB
tblDef := sqlmodel.NewTableDef(source.MonotableName, colNames, colKinds)
db, err := job.destDB.DB(ctx)
if err != nil {
return err
}
err = job.destDB.SQLDriver().CreateTable(ctx, db, tblDef)
if err != nil {
return errz.Wrapf(err, "import %s: failed to create dest scratch table", TypeJSONA)
}
recMeta, err := getRecMeta(ctx, job.destDB, tblDef)
if err != nil {
return err
}
r, err := job.openFn()
if err != nil {
return errz.Err(err)
}
defer lg.WarnIfCloseError(log, lgm.CloseFileReader, r)
insertWriter := libsq.NewDBWriter(
job.destDB,
tblDef.Name,
driver.OptTuningRecChanSize.Get(job.destDB.Source().Options),
)
var cancelFn context.CancelFunc
ctx, cancelFn = context.WithCancel(ctx)
defer cancelFn()
recordCh, errCh, err := insertWriter.Open(ctx, cancelFn, recMeta)
if err != nil {
return err
}
// After startInsertJSONA returns, we still need to wait
// for the insertWriter to finish.
err = startInsertJSONA(ctx, recordCh, errCh, r, readMungeFns)
if err != nil {
return err
}
inserted, err := insertWriter.Wait()
if err != nil {
return err
}
log.Debug("Inserted rows",
lga.Count, inserted,
lga.Target, source.Target(job.destDB.Source(), tblDef.Name),
)
return nil
}
// startInsertJSONA reads JSON records from r and sends
// them on recordCh.
func startInsertJSONA(ctx context.Context, recordCh chan<- record.Record, errCh <-chan error, r io.Reader,
mungeFns []kind.MungeFunc,
) error {
defer close(recordCh)
sc := bufio.NewScanner(r)
var line []byte
var err error
for sc.Scan() {
if err = sc.Err(); err != nil {
return errz.Err(err)
}
line = sc.Bytes()
if len(line) == 0 {
// Probably want to skip blank lines? Maybe
continue
}
// Each line of JSONA must open with left bracket
if line[0] != '[' {
return errz.New("malformed JSONA input")
}
// If the line is JSONA, it should marshal into []any
var rec []any
err = stdj.Unmarshal(line, &rec)
if err != nil {
return errz.Err(err)
}
for i := 0; i < len(rec); i++ {
fn := mungeFns[i]
if fn != nil {
var v any
v, err = fn(rec[i])
if err != nil {
return errz.Err(err)
}
rec[i] = v
}
}
select {
case err = <-errCh:
return err
case <-ctx.Done():
return ctx.Err()
case recordCh <- rec:
}
}
if err = sc.Err(); err != nil {
return errz.Err(err)
}
return nil
}
// detectColKindsJSONA reads JSONA lines from r, and returns
// the kind of each field. The []readMungeFunc may contain a munge
// func that should be applied to each value (or the element may be nil).
func detectColKindsJSONA(ctx context.Context, r io.Reader, sampleSize int) ([]kind.Kind, []kind.MungeFunc, error) {
var (
err error
totalLineCount int
// jLineCount is the number of JSONA lines (totalLineCount minus empty lines)
jLineCount int
line []byte
kinds []kind.Kind
detectors []*kind.Detector
mungeFns []kind.MungeFunc
)
sc := bufio.NewScanner(r)
for sc.Scan() {
select {
case <-ctx.Done():
return nil, nil, ctx.Err()
default:
}
if jLineCount > sampleSize {
break
}
if err = sc.Err(); err != nil {
return nil, nil, errz.Err(err)
}
line = sc.Bytes()
totalLineCount++
if len(line) == 0 {
// Probably want to skip blank lines? Maybe
continue
}
jLineCount++
// Each line of JSONA must open with left bracket
if line[0] != '[' {
return nil, nil, errz.New("line does not begin with left bracket '['")
}
// If the line is JSONA, it should marshall into []any
var vals []any
err = stdj.Unmarshal(line, &vals)
if err != nil {
return nil, nil, errz.Err(err)
}
if len(vals) == 0 {
return nil, nil, errz.Errorf("zero field count at line %d", totalLineCount)
}
if kinds == nil {
kinds = make([]kind.Kind, len(vals))
mungeFns = make([]kind.MungeFunc, len(vals))
detectors = make([]*kind.Detector, len(vals))
for i := range detectors {
detectors[i] = kind.NewDetector()
}
}
if len(vals) != len(kinds) {
return nil, nil, errz.Errorf("inconsistent field count: expected %d but got %d at line %d",
len(kinds), len(vals), totalLineCount)
}
for i, val := range vals {
val = maybeFloatToInt(val)
detectors[i].Sample(val)
}
}
if jLineCount == 0 {
return nil, nil, errz.New("empty JSONA input")
}
for i := range kinds {
kinds[i], mungeFns[i], err = detectors[i].Detect()
if err != nil {
return nil, nil, err
}
if kinds[i] == kind.Null {
kinds[i] = kind.Text
}
}
return kinds, mungeFns, nil
}
// maybeFloatToInt returns an int64 if val is a float64 with a
// round integer value. If val is not a float64, it is returned
// unchanged.
//
// The JSON decoder decodes numbers into float64.
// We don't want that if the number is really an integer
// (especially important for id columns).
// So, if the float64 has zero after the decimal point '.' (that
// is to say, it's a round float like 1.0), we return the int64 value.
func maybeFloatToInt(val any) any {
if f64, ok := val.(float64); ok {
floor := math.Floor(f64)
if f64-floor == 0 {
return int64(floor)
}
}
return val
}