forked from FerretDB/FerretDB
/
backend.go
163 lines (133 loc) · 4.13 KB
/
backend.go
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// Copyright 2021 FerretDB Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package hana
import (
"context"
"database/sql"
"github.com/prometheus/client_golang/prometheus"
"go.uber.org/zap"
"github.com/FerretDB/FerretDB/internal/backends"
"github.com/FerretDB/FerretDB/internal/util/fsql"
"github.com/FerretDB/FerretDB/internal/util/lazyerrors"
"github.com/FerretDB/FerretDB/internal/util/state"
)
// backend implements backends.Backend interface.
type backend struct {
hdb *fsql.DB
l *zap.Logger
}
// NewBackendParams represents the parameters of NewBackend function.
//
//nolint:vet // for readability
type NewBackendParams struct {
URI string
L *zap.Logger
P *state.Provider
BatchSize int
}
// NewBackend creates a new Backend.
func NewBackend(params *NewBackendParams) (backends.Backend, error) {
db, err := sql.Open("hdb", params.URI)
if err != nil {
return nil, err
}
hdb := fsql.WrapDB(db, "hana", params.L)
hdb.BatchSize = params.BatchSize
return backends.BackendContract(&backend{
hdb: hdb,
l: params.L,
}), nil
}
// Close implements backends.Backend interface.
func (b *backend) Close() {
if b.hdb.Close() != nil {
panic("could not close hana db connection")
}
}
// Status implements backends.Backend interface.
func (b *backend) Status(ctx context.Context, params *backends.StatusParams) (*backends.StatusResult, error) {
sqlStmt := "SELECT DISTINCT(SCHEMA_NAME) FROM M_TABLES WHERE TABLE_TYPE = 'COLLECTION'"
// List out all schemas
rows, err := b.hdb.QueryContext(ctx, sqlStmt)
if err != nil {
return nil, lazyerrors.Error(err)
}
defer rows.Close()
var res backends.StatusResult
for rows.Next() {
// db name is schema name from here on out
var dbName string
if err = rows.Scan(&dbName); err != nil {
return nil, lazyerrors.Error(err)
}
list, errDB := newDatabase(b.hdb, dbName).ListCollections(ctx, new(backends.ListCollectionsParams))
if errDB != nil {
return nil, lazyerrors.Error(err)
}
res.CountCollections += int64(len(list.Collections))
for _, cInfo := range list.Collections {
if cInfo.Capped() {
res.CountCappedCollections++
}
}
}
if err = rows.Err(); err != nil {
return nil, lazyerrors.Error(err)
}
return &res, nil
}
// Database implements backends.Backend interface.
func (b *backend) Database(name string) (backends.Database, error) {
return newDatabase(b.hdb, name), nil
}
// ListDatabases implements backends.Backend interface.
//
//nolint:lll // for readability
func (b *backend) ListDatabases(ctx context.Context, params *backends.ListDatabasesParams) (*backends.ListDatabasesResult, error) {
rows, err := b.hdb.QueryContext(ctx, "SELECT SCHEMA_NAME FROM SCHEMAS")
if err != nil {
return nil, err
}
defer rows.Close()
var databases []backends.DatabaseInfo
for rows.Next() {
var dbName string
if err := rows.Scan(&dbName); err != nil {
return nil, err
}
databases = append(databases, backends.DatabaseInfo{Name: dbName})
}
return &backends.ListDatabasesResult{Databases: databases}, nil
}
// DropDatabase implements backends.Backend interface.
func (b *backend) DropDatabase(ctx context.Context, params *backends.DropDatabaseParams) error {
dropped, err := dropSchema(ctx, b.hdb, params.Name)
if err != nil {
return getHanaErrorIfExists(err)
}
if !dropped {
return backends.NewError(backends.ErrorCodeDatabaseDoesNotExist, err)
}
return nil
}
// Describe implements prometheus.Collector.
func (b *backend) Describe(ch chan<- *prometheus.Desc) {
}
// Collect implements prometheus.Collector.
func (b *backend) Collect(ch chan<- prometheus.Metric) {
}
// check interfaces
var (
_ backends.Backend = (*backend)(nil)
)