surrealpatch/db/db.go
2018-04-25 00:00:36 +01:00

264 lines
6.7 KiB
Go

// Copyright © 2016 Abcum Ltd
//
// 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 db
import (
"io"
"context"
"net/http"
"github.com/abcum/fibre"
"github.com/abcum/surreal/cnf"
"github.com/abcum/surreal/kvs"
"github.com/abcum/surreal/log"
"github.com/abcum/surreal/sql"
"github.com/abcum/surreal/util/data"
"github.com/abcum/surreal/util/uuid"
_ "github.com/abcum/surreal/kvs/mysql"
_ "github.com/abcum/surreal/kvs/rixxdb"
)
var db *kvs.DS
// Response is a response from the database
type Response struct {
Time string `codec:"time,omitempty"`
Status string `codec:"status,omitempty"`
Detail string `codec:"detail,omitempty"`
Result []interface{} `codec:"result,omitempty"`
}
// Dispatch is a dispatch from the database
type Dispatch struct {
Query string `codec:"query,omitempty"`
Action string `codec:"action,omitempty"`
Result interface{} `codec:"result,omitempty"`
}
// Setup sets up the connection with the data layer
func Setup(opts *cnf.Options) (err error) {
log.WithPrefix("db").Infof("Starting database")
db, err = kvs.New(opts)
return
}
// Exit shuts down the connection with the data layer
func Exit() (err error) {
log.WithPrefix("db").Infof("Gracefully shutting down database")
for id, so := range sockets {
deregister(so.fibre, id)()
}
return db.Close()
}
// Import loads database operations from a reader.
// This can be used to playback a database snapshot
// into an already running database.
func Import(r io.Reader) (err error) {
return db.Import(r)
}
// Export saves all database operations to a writer.
// This can be used to save a database snapshot
// to a secondary file or stream.
func Export(w io.Writer) (err error) {
return db.Export(w)
}
// Begin begins a new read / write transaction
// with the underlying database, and returns
// the transaction, or any error which occured.
func Begin(rw bool) (txn kvs.TX, err error) {
return db.Begin(context.Background(), rw)
}
// Socket registers a websocket for live queries
// returning two callback functions. The first
// function should be called when the websocket
// connects, and the second function should be
// called when the websocket disconnects.
func Socket(fib *fibre.Context, id string) (beg, end func()) {
return register(fib, id), deregister(fib, id)
}
// Execute parses a single sql query, or multiple
// sql queries, and executes them serially against
// the underlying data layer.
func Execute(fib *fibre.Context, txt interface{}, vars map[string]interface{}) (out []*Response, err error) {
// Parse the received SQL batch query strings
// into SQL ASTs, using any immutable preset
// variables if set.
ast, err := sql.Parse(fib, txt)
if err != nil {
return
}
// Process the parsed SQL batch query using
// the predefined query variables.
return Process(fib, ast, vars)
}
// Process takes a parsed set of sql queries and
// executes them serially against the underlying
// data layer.
func Process(fib *fibre.Context, ast *sql.Query, vars map[string]interface{}) (out []*Response, err error) {
// If no preset variables have been defined
// then ensure that the variables is
// instantiated for future use.
if vars == nil {
vars = make(map[string]interface{})
}
// Ensure that we have a unique id assigned
// to this fibre connection, as we need it
// to detect unique websocket notifications.
if fib.Get(ctxKeyId) == nil {
fib.Set(ctxKeyId, uuid.New().String())
}
// Ensure that the IP address of the
// user signing in is available so that
// it can be used within signin queries.
vars[varKeyIp] = fib.IP().String()
// Ensure that the website origin of the
// user signing in is available so that
// it can be used within signin queries.
vars[varKeyOrigin] = fib.Origin()
// Ensure that the current authentication
// data is made available as a runtime
// variable to the query layer.
vars[varKeyAuth] = fib.Get(varKeyAuth).(*cnf.Auth).Data
// Ensure that the current authentication
// scope is made available as a runtime
// variable to the query layer.
vars[varKeyScope] = fib.Get(varKeyAuth).(*cnf.Auth).Scope
// Create a new context so that we can quit
// all goroutine workers if the http client
// itself is closed before finishing.
ctx, quit := context.WithCancel(fib.Context())
// When this function has finished ensure
// that we cancel this context so that any
// associated resources are released.
defer quit()
// Get the unique id for this connection
// so that we can assign it to the context
// and detect any websocket notifications.
id := fib.Get(ctxKeyId).(string)
// Assign the fibre request context id to
// the context so that we can log the id
// together with the request.
ctx = context.WithValue(ctx, ctxKeyId, id)
// Assign any global connection variables
// to the context so that we can retrieve
// the variables from within any queries.
keep := fib.Get(varKeyKeep)
ctx = context.WithValue(ctx, ctxKeyKeep, keep)
// Assign the authentication data to the
// context so that we can log the auth kind
// and the auth variable data to the request.
auth := fib.Get(varKeyAuth).(*cnf.Auth)
ctx = context.WithValue(ctx, ctxKeyAuth, auth.Data)
ctx = context.WithValue(ctx, ctxKeyKind, auth.Kind)
// Add the request variables to the context
// so that we can access them at a later
// stage within the nested callbacks.
ctx = context.WithValue(ctx, ctxKeyVars, data.Consume(vars))
// If the current connection is a normal http
// connection then force quit any running
// queries if the http socket closes.
if _, ok := fib.Response().Writer().(http.CloseNotifier); ok {
exit := fib.Response().CloseNotify()
done := make(chan struct{})
defer close(done)
go func() {
select {
case <-done:
case <-exit:
quit()
}
}()
}
// Create a new query executor with the query
// details, and the current runtime variables
// and execute the queries within.
executor := newExecutor()
go executor.execute(ctx, ast)
// Wait for all of the processed queries to
// return results, buffer the output, and
// return the output when finished.
for {
select {
case <-ctx.Done():
return nil, fibre.NewHTTPError(504)
case res, open := <-executor.send:
if !open {
return
}
out = append(out, res)
}
}
return
}