Intégration d'un point d'entrée GraphQL et d'un connecteur pour

PostgreSQL

- Possibilité de migrer le schéma de la base de données via drapeau
- Génération du code GraphQL avec https://gqlgen.com/

internal/database/migration.go

@@ -0,0 +1,79 @@
+package database
+
+import (
+	"context"
+
+	"github.com/jackc/pgx/v4"
+
+	"github.com/jackc/pgx/v4/pgxpool"
+	"github.com/pkg/errors"
+	"gitlab.com/wpetit/goweb/middleware/container"
+)
+
+type MigrationFunc func(ctx context.Context, tx pgx.Tx) error
+
+type Migration struct {
+	version string
+	up      MigrationFunc
+	down    MigrationFunc
+}
+
+func (m *Migration) Version() string {
+	return m.version
+}
+
+func (m *Migration) Up(ctx context.Context) error {
+	pool, err := m.getDatabaseService(ctx)
+	if err != nil {
+		return err
+	}
+
+	err = WithTx(ctx, pool, func(ctx context.Context, tx pgx.Tx) error {
+		return m.up(ctx, tx)
+	})
+
+	if err != nil {
+		return errors.Wrap(err, "could not apply up migration")
+	}
+
+	return nil
+}
+
+func (m *Migration) Down(ctx context.Context) error {
+	pool, err := m.getDatabaseService(ctx)
+	if err != nil {
+		return err
+	}
+
+	err = WithTx(ctx, pool, func(ctx context.Context, tx pgx.Tx) error {
+		return m.down(ctx, tx)
+	})
+
+	if err != nil {
+		return errors.Wrap(err, "could not apply down migration")
+	}
+
+	return nil
+}
+
+func (m *Migration) getDatabaseService(ctx context.Context) (*pgxpool.Pool, error) {
+	ctn, err := container.From(ctx)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not retrieve service container")
+	}
+
+	pool, err := From(ctn)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not retrieve database service")
+	}
+
+	return pool, nil
+}
+
+func NewMigration(version string, up, down MigrationFunc) *Migration {
+	return &Migration{
+		version: version,
+		up:      up,
+		down:    down,
+	}
+}

internal/database/provider.go

@@ -0,0 +1,24 @@
+package database
+
+import (
+	"context"
+
+	"github.com/jackc/pgx/v4/pgxpool"
+	"github.com/pkg/errors"
+	"gitlab.com/wpetit/goweb/service"
+)
+
+func ServiceProvider(dsn string) service.Provider {
+	pool, err := pgxpool.Connect(context.Background(), dsn)
+	if err != nil {
+		err = errors.Wrap(err, "could not connect to database")
+	}
+
+	return func(ctn *service.Container) (interface{}, error) {
+		if err != nil {
+			return nil, err
+		}
+
+		return pool, nil
+	}
+}

internal/database/service.go

@@ -0,0 +1,34 @@
+package database
+
+import (
+	"github.com/jackc/pgx/v4/pgxpool"
+	"github.com/pkg/errors"
+	"gitlab.com/wpetit/goweb/service"
+)
+
+const ServiceName service.Name = "database"
+
+// From retrieves the database pool service in the given container
+func From(container *service.Container) (*pgxpool.Pool, error) {
+	service, err := container.Service(ServiceName)
+	if err != nil {
+		return nil, errors.Wrapf(err, "error while retrieving '%s' service", ServiceName)
+	}
+
+	srv, ok := service.(*pgxpool.Pool)
+	if !ok {
+		return nil, errors.Errorf("retrieved service is not a valid '%s' service", ServiceName)
+	}
+
+	return srv, nil
+}
+
+// Must retrieves the database pool service in the given container or panic otherwise
+func Must(container *service.Container) *pgxpool.Pool {
+	srv, err := From(container)
+	if err != nil {
+		panic(err)
+	}
+
+	return srv
+}

internal/database/tx.go

@@ -0,0 +1,38 @@
+package database
+
+import (
+	"context"
+
+	"github.com/jackc/pgx/v4"
+	"github.com/jackc/pgx/v4/pgxpool"
+	"github.com/pkg/errors"
+)
+
+func WithTx(ctx context.Context, pool *pgxpool.Pool, fn func(context.Context, pgx.Tx) error) error {
+	tx, err := pool.BeginTx(ctx, pgx.TxOptions{})
+	if err != nil {
+		return errors.Wrap(err, "could not begin transaction")
+	}
+
+	defer func() {
+		if err := tx.Rollback(ctx); err != nil && !errors.Is(err, pgx.ErrTxClosed) {
+			panic(errors.Wrap(err, "could not rollback transaction"))
+		}
+	}()
+
+	if err := fn(ctx, tx); err != nil {
+		err := errors.Wrap(err, "could not apply down migration")
+
+		if rollbackErr := tx.Rollback(ctx); rollbackErr != nil {
+			return errors.Wrap(err, rollbackErr.Error())
+		}
+
+		return err
+	}
+
+	if err := tx.Commit(ctx); err != nil {
+		return errors.Wrap(err, "could not commit transaction")
+	}
+
+	return nil
+}

internal/database/version_resolver.go

@@ -0,0 +1,94 @@
+package database
+
+import (
+	"context"
+
+	"github.com/jackc/pgx/v4"
+	"github.com/jackc/pgx/v4/pgxpool"
+	"github.com/pkg/errors"
+)
+
+type VersionResolver struct {
+	pool *pgxpool.Pool
+}
+
+func (r *VersionResolver) Current(ctx context.Context) (string, error) {
+	var version string
+
+	err := WithTx(ctx, r.pool, func(ctx context.Context, tx pgx.Tx) error {
+		err := tx.QueryRow(ctx, `SELECT version FROM database_schema WHERE is_current = true;`).
+			Scan(&version)
+
+		if errors.Is(err, pgx.ErrNoRows) {
+			return nil
+		}
+
+		return err
+	})
+
+	if err != nil {
+		return "", errors.Wrap(err, "could execute version resolver init transaction")
+	}
+
+	return version, nil
+}
+
+func (r *VersionResolver) Set(ctx context.Context, version string) error {
+	err := WithTx(ctx, r.pool, func(ctx context.Context, tx pgx.Tx) error {
+		if version != "" {
+			_, err := tx.Exec(ctx, `
+				INSERT INTO database_schema (version, is_current, migrated_at)
+				VALUES
+					(
+						$1,
+						true,
+						now()
+					) 
+				ON CONFLICT ON CONSTRAINT unique_version 
+				DO UPDATE SET migrated_at = now(), is_current = true;
+			`, version)
+
+			if err != nil {
+				return err
+			}
+		}
+
+		_, err := tx.Exec(ctx, `
+			UPDATE database_schema SET is_current = false, migrated_at = null WHERE version <> $1;
+		`, version)
+
+		return err
+	})
+
+	if err != nil {
+		return errors.Wrap(err, "could not update schema version")
+	}
+
+	return nil
+}
+
+func (r *VersionResolver) Init(ctx context.Context) error {
+	err := WithTx(ctx, r.pool, func(ctx context.Context, tx pgx.Tx) error {
+		_, err := tx.Exec(ctx, `
+		CREATE TABLE IF NOT EXISTS database_schema(
+			version TEXT NOT NULL,
+			migrated_at TIME,
+			is_current BOOLEAN,
+			CONSTRAINT unique_version UNIQUE(version)
+		);`)
+
+		return err
+	})
+
+	if err != nil {
+		return errors.Wrap(err, "could execute version resolver init transaction")
+	}
+
+	return nil
+}
+
+func NewVersionResolver(pool *pgxpool.Pool) *VersionResolver {
+	return &VersionResolver{
+		pool: pool,
+	}
+}