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Update KV get/put and prepared batch examples. #177

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Update KV get/put and prepared batch examples. #177

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85 changes: 49 additions & 36 deletions client/doc.go
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Original file line number Diff line number Diff line change
Expand Up @@ -29,15 +29,23 @@ The simplest way to use the client is through the Call method. Call
synchronously invokes the method and returns the reply and an
error. The example below shows a get and a put.

kv := client.NewKV("localhost:8080", tlsConfig)

getResp := &proto.GetResponse{}
if err := kv.Call(proto.Get, proto.GetArgs(proto.Key("a")), getResp); err != nil {
log.Fatal(err)
}
if _, err := kv.Call(proto.Put, proto.PutArgs(proto.Key("b"), getResp.Value.Bytes)) err != nil {
log.Fatal(err)
}
host := "localhost:8080"
sender := client.NewHTTPSender(host, &http.Transport{
TLSClientConfig: rpc.LoadInsecureTLSConfig().Config(),
})
kv := client.NewKV(sender, nil)
kv.User = storage.UserRoot

getResp := &proto.GetResponse{}
if err := kv.Call(proto.Get, proto.GetArgs(proto.Key("a")), getResp); err != nil {
log.Fatal(err)
}

value := getResp.Value.Bytes
putResp := &proto.PutResponse{}
if err := kv.Call(proto.Put, proto.PutArgs(proto.Key("b"), value), putResp); err != nil {
log.Fatal(err)
}

The API is synchronous, but accommodates efficient parallel updates
and queries using the Prepare method. An arbitrary number of Prepare
Expand All @@ -50,33 +58,38 @@ transaction must be used to guarantee atomicity. A simple example of
using the API which does two scans in parallel and then sends a
sequence of puts in parallel:

kv := client.NewKV("localhost:8080", tlsConfig)

acResp, xzResp := &proto.ScanResponse{}, &proto.ScanResponse{}
kv.Prepare(proto.Scan, proto.ScanArgs(proto.Key("a"), proto.Key("c")), acResp)
kv.Prepare(proto.Scan, proto.ScanArgs(proto.Key("x"), proto.Key("z")), xzResp)

// Flush sends both scans in parallel and returns first error or nil.
if err := kv.Flush(); err != nil {
log.Fatal(err)
}

// Append maximum value from "a"-"c" to all values from "x"-"z".
max := []byte(nil)
for _, keyVal := range acResp.Rows {
if bytes.Compare(max, keyVal.Value.Bytes) < 0 {
max = keyVal.Value.Bytes
}
}
for keyVal := range xzResp.Rows {
putReq := proto.PutArgs(keyVal.Key, bytes.Join([][]byte{keyVal.Value.Bytes, max}, []byte(nil)))
kv.Prepare(proto.Put, putReq, &proto.PutReponse{})
}

// Flush all puts for parallel execution.
if _, err := kv.Flush(); err != nil {
log.Fatal(err)
}
host := "localhost:8080"
sender := client.NewHTTPSender(host, &http.Transport{
TLSClientConfig: rpc.LoadInsecureTLSConfig().Config(),
})
kv := client.NewKV(sender, nil)
kv.User = storage.UserRoot

acResp, xzResp := &proto.ScanResponse{}, &proto.ScanResponse{}
kv.Prepare(proto.Scan, proto.ScanArgs(proto.Key("a"), proto.Key("c").Next(), 3), acResp)
kv.Prepare(proto.Scan, proto.ScanArgs(proto.Key("x"), proto.Key("z").Next(), 3), xzResp)

// Flush sends both scans in parallel and returns first error or nil.
if err := kv.Flush(); err != nil {
log.Fatal(err)
}

// Append maximum value from "a"-"c" to all values from "x"-"z".
max := []byte(nil)
for _, keyVal := range acResp.Rows {
if bytes.Compare(max, keyVal.Value.Bytes) < 0 {
max = keyVal.Value.Bytes
}
}
for _, keyVal := range xzResp.Rows {
putReq := proto.PutArgs(keyVal.Key, bytes.Join([][]byte{keyVal.Value.Bytes, max}, []byte(nil)))
kv.Prepare(proto.Put, putReq, &proto.PutResponse{})
}

// Flush all puts for parallel execution.
if err := kv.Flush(); err != nil {
log.Fatal(err)
}

Transactions are supported through the RunTransaction() method, which
takes a retryable function, itself composed of the same simple mix of
Expand Down