Fixes https://github.com/tendermint/tendermint/issues/1162
Databases as a service!
Can now access Databases as a remote service
via gRPC for performance and easy deployment.
The caveat is that each service is stateful in regards to
the DB i.e. each unique service uses only one unique DB
but nonetheless multiple clients can access it.
A full standalone example
```go
package main
import (
"bytes"
"context"
"log"
grpcdb "github.com/tendermint/tmlibs/grpcdb"
protodb "github.com/tendermint/tmlibs/proto"
)
func main() {
addr := ":8998"
go func() {
if err := grpcdb.BindRemoteDBServer(addr); err != nil {
log.Fatalf("BindRemoteDBServer: %v", err)
}
}()
client, err := grpcdb.NewClient(addr, false)
if err != nil {
log.Fatalf("Failed to create grpcDB client: %v", err)
}
ctx := context.Background()
// 1. Initialize the DB
in := &protodb.Init{
Type: "leveldb",
Name: "grpc-uno-test",
Dir: ".",
}
if _, err := client.Init(ctx, in); err != nil {
log.Fatalf("Init error: %v", err)
}
// 2. Now it can be used!
query1 := &protodb.Entity{Key: []byte("Project"), Value:
[]byte("Tmlibs-on-gRPC")}
if _, err := client.SetSync(ctx, query1); err != nil {
log.Fatalf("SetSync err: %v", err)
}
query2 := &protodb.Entity{Key: []byte("Project")}
read, err := client.Get(ctx, query2)
if err != nil {
log.Fatalf("Get err: %v", err)
}
if g, w := read.Value, []byte("Tmlibs-on-gRPC"); !bytes.Equal(g, w) {
log.Fatalf("got= (%q ==> % X)\nwant=(%q ==> % X)", g, g, w, w)
}
}
```
* Add CacheDB & SimpleMap
* Generic memBatch; Fix cLevelDB tests
* CacheWrap() for CacheDB and MemDB
* Change Iterator to match LeviGo Iterator
* Fixes from review
* cacheWrapWriteMutex and some race fixes
* Use tmlibs/common
* NewCWWMutex is exposed. DB can be CacheWrap'd
* Remove GetOK, not needed
* Fsdb (#72)
* Add FSDB
* Review fixes from Anton
* Review changes
* Fixes from review
Jeremiah Andrews
Ethan Buchman
Christopher Goes
Emmanuel T Odeke
Zaki Manian
Jae Kwon
Zach Ramsay
Anton Kaliaev
Ethan Frey