Simplified the abstractions to remotedb, a package that
allows clients to use whatever database they can in client
code without having to switch out their code e.g
```go
client, err := remotedb.NewInsecure(":9888")
...
// Just like they'd initialize locally
in := &remotedb.Init{
Name: "test-remote-db",
Type: "leveldb",
Dir: "/tmp/dbs",
}
if err := client.InitRemote(in); err != nil {
log.Fatalf("Failed to initialize the database")
}
v1 := client.Get(k1)
client.Set(k9, dog)
for itr := client.Iterator(a1, z1); itr.Valid(); itr.Next() {
k, v := itr.Key(), itr.Value()
dom := itr.Domain()
...
}
```
* Added some docs for NewClient, BindServer, *server.Init
* Security level clarified, whether "secure" for https
or "insecure" for non-https gRPC connections.
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)
}
}
```
