feat: added repo export/import streaming methods

internal/adapters/sqlite/sqlite.go

@@ -3,6 +3,7 @@ package sqlite
 import (
 	"context"
 	"database/sql"
+	"fmt"
 	sq "github.com/Masterminds/squirrel"
 	"github.com/abelith/spellbook/internal/errors"
 	"github.com/abelith/spellbook/internal/models"
@@ -45,17 +46,10 @@ func (r *Repo) Init(ctx context.Context) error {
 }
 
 func (r *Repo) Add(ctx context.Context, spell models.Spell) error {
-	tags := strings.Join(spell.Tags, ",")
-
-	_, err := sq.Insert("spells").
-		Columns("name", "spell", "short_desc", "description", "tags").
-		Values(spell.Name, spell.Spell, spell.ShortDesc, spell.Description, tags).
-		PlaceholderFormat(sq.Question).
-		RunWith(r.db).
-		ExecContext(ctx)
-	if err != nil {
+	if _, err := insertSpell(ctx, r.db, spell); err != nil {
 		return err
 	}
+
 	return nil
 }
 
@@ -148,6 +142,97 @@ func (r *Repo) GetMany(ctx context.Context, query models.SearchQuery) ([]models.
 	return spells, nil
 }
 
+func (r *Repo) Import(ctx context.Context, ch <-chan models.Spell) error {
+	return r.runTx(ctx, func(tx *sql.Tx) error {
+		cache := sq.NewStmtCache(tx)
+		defer cache.Clear()
+
+		for {
+			select {
+			case <-ctx.Done():
+				return ctx.Err()
+			case spell, ok := <-ch:
+				if !ok {
+					return nil
+				}
+
+				_, err := insertSpell(ctx, cache, spell)
+				if err != nil {
+					return err
+				}
+			}
+		}
+	})
+}
+
+func (r *Repo) Count(ctx context.Context) (int, error) {
+	var count int
+	err := sq.Select("COUNT(*)").
+		From("spells").
+		RunWith(r.db).
+		ScanContext(ctx, &count)
+	if err != nil {
+		return 0, err
+	}
+
+	return count, nil
+}
+
+func (r *Repo) Export(ctx context.Context) (<-chan models.Spell, <-chan error, error) {
+	ch := make(chan models.Spell, 1)
+	errCh := make(chan error, 1)
+	rows, err := sq.Select("id", "name", "spell", "short_desc", "description", "tags").
+		From("spells").
+		RunWith(r.db).
+		QueryContext(ctx)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	go func() {
+		defer close(errCh)
+		defer close(ch)
+		defer rows.Close()
+
+		for rows.Next() {
+			spell, err := scanSpell(rows)
+			if err != nil {
+				errCh <- err
+				return
+			}
+
+			select {
+			case <-ctx.Done():
+				errCh <- ctx.Err()
+				return
+			case ch <- spell:
+			}
+		}
+
+		if err := rows.Err(); err != nil {
+			errCh <- err
+		}
+	}()
+
+	return ch, errCh, nil
+}
+
+func (r *Repo) runTx(ctx context.Context, f func(tx *sql.Tx) error) error {
+	tx, err := r.db.BeginTx(ctx, &sql.TxOptions{Isolation: sql.LevelSerializable})
+	if err != nil {
+		return fmt.Errorf("failed to begin tx: %w", err)
+	}
+
+	if err := f(tx); err != nil {
+		if rbErr := tx.Rollback(); rbErr != nil {
+			return fmt.Errorf("err: %v, rollback err: %w", err, rbErr)
+		}
+		return err
+	}
+
+	return tx.Commit()
+}
+
 func scanSpell(row scanner) (models.Spell, error) {
 	spell := models.Spell{}
 	tagsString := ""
@@ -162,3 +247,14 @@ func scanSpell(row scanner) (models.Spell, error) {
 
 	return spell, nil
 }
+
+func insertSpell(ctx context.Context, runner sq.BaseRunner, spell models.Spell) (sql.Result, error) {
+	tags := strings.Join(spell.Tags, ",")
+
+	return sq.Insert("spells").
+		Columns("name", "spell", "short_desc", "description", "tags").
+		Values(spell.Name, spell.Spell, spell.ShortDesc, spell.Description, tags).
+		PlaceholderFormat(sq.Question).
+		RunWith(runner).
+		ExecContext(ctx)
+}

internal/application/application.go

@@ -12,11 +12,14 @@ type SpellCaster interface {
 type SpellCommand interface {
 	Add(ctx context.Context, spell models.Spell) error
 	Delete(ctx context.Context, spellName string) error
+	Import(ctx context.Context, ch <-chan models.Spell) error
 }
 
 type SpellQuery interface {
 	Get(ctx context.Context, spellName string) (models.Spell, error)
 	GetMany(ctx context.Context, query models.SearchQuery) ([]models.Spell, error)
+	Count(ctx context.Context) (int, error)
+	Export(ctx context.Context) (<-chan models.Spell, <-chan error, error)
 }
 
 type Application struct {