From e12d17e4827a522ca475835de13d5f83ec545453 Mon Sep 17 00:00:00 2001
From: Manish R Jain <manishrjain@gmail.com>
Date: Tue, 13 Oct 2015 19:28:10 +1100
Subject: [PATCH] Transform to Flatbuffer + write to and read from leveldb
---
plist/.gitignore | 1 +
plist/main.go | 101 +++++++++++++++++++++++++++++++++++++++++++++++
types.fbs | 8 ++++
types/Uid.go | 43 ++++++++++++++++++++
x/x.go | 60 ++++++++++++++++++++++++++++
5 files changed, 213 insertions(+)
create mode 100644 plist/.gitignore
create mode 100644 plist/main.go
create mode 100644 types.fbs
create mode 100644 types/Uid.go
create mode 100644 x/x.go
diff --git a/plist/.gitignore b/plist/.gitignore
new file mode 100644
index 00000000..2634eed2
--- /dev/null
+++ b/plist/.gitignore
@@ -0,0 +1 @@
+/plist
diff --git a/plist/main.go b/plist/main.go
new file mode 100644
index 00000000..f118cfe6
--- /dev/null
+++ b/plist/main.go
@@ -0,0 +1,101 @@
+package main
+
+import (
+ "fmt"
+ "io/ioutil"
+ "time"
+
+ "github.com/Sirupsen/logrus"
+ "github.com/google/flatbuffers/go"
+ "github.com/manishrjain/dgraph/types"
+ "github.com/syndtr/goleveldb/leveldb"
+ "github.com/syndtr/goleveldb/leveldb/filter"
+ "github.com/syndtr/goleveldb/leveldb/opt"
+)
+
+var log = logrus.WithField("package", "plist")
+
+type Triple struct {
+ Entity string
+ Attribute string
+ Value interface{}
+ ValueId string
+ Source string
+ Timestamp time.Time
+}
+
+/*
+func addTriple(w http.ResponseWriter, r *http.Request) {
+ if r.Method != "POST" {
+ x.SetStatus(w, x.E_INVALID_METHOD, "Should be POST")
+ return
+ }
+
+ var t Triple
+ if ok := x.ParseRequest(w, r, &t); !ok {
+ return
+ }
+
+ log.Debug(t)
+}
+*/
+
+func main() {
+ path, err := ioutil.TempDir("", "dgraphldb_")
+ if err != nil {
+ log.Fatal(err)
+ return
+ }
+ opt := &opt.Options{
+ Filter: filter.NewBloomFilter(10),
+ }
+ db, err := leveldb.OpenFile(path, opt)
+ if err != nil {
+ log.Fatal(err)
+ return
+ }
+ fmt.Println("Using path", path)
+
+ batch := new(leveldb.Batch)
+ b := flatbuffers.NewBuilder(0)
+ oi := b.CreateString("mrjn is a smart kid")
+ on := b.CreateString("His name is jain")
+ types.UidStart(b)
+ types.UidAddId(b, oi)
+ types.UidAddName(b, on)
+ oe := types.UidEnd(b)
+ b.Finish(oe)
+ fmt.Println("Value byte size:", len(b.Bytes))
+
+ key := "Some long id"
+ batch.Put([]byte(key), b.Bytes[b.Head():])
+ if err := db.Write(batch, nil); err != nil {
+ log.Fatal(err)
+ return
+ }
+ fmt.Println("Wrote key value out to leveldb. Reading back")
+ if err := db.Close(); err != nil {
+ log.Fatal(err)
+ return
+ }
+
+ db, err = leveldb.OpenFile(path, opt)
+ if err != nil {
+ log.Fatal(err)
+ return
+ }
+
+ val, err := db.Get([]byte(key), nil)
+ if err != nil {
+ log.Fatal(err)
+ return
+ }
+ fmt.Println("Value byte size from Leveldb:", len(val))
+
+ uid := types.GetRootAsUid(val, 0)
+ fmt.Println("buffer.uid id =", string(uid.Id()))
+ fmt.Println("buffer.uid name =", string(uid.Name()))
+ // http.HandleFunc("/add", addTriple)
+ // http.ListenAndServe(":8080", nil)
+
+}
diff --git a/types.fbs b/types.fbs
new file mode 100644
index 00000000..d25c25bb
--- /dev/null
+++ b/types.fbs
@@ -0,0 +1,8 @@
+namespace types;
+
+table Uid {
+ id:string;
+ name:string;
+}
+
+root_type Uid;
diff --git a/types/Uid.go b/types/Uid.go
new file mode 100644
index 00000000..4695ecc3
--- /dev/null
+++ b/types/Uid.go
@@ -0,0 +1,43 @@
+// automatically generated, do not modify
+
+package types
+
+import (
+ flatbuffers "github.com/google/flatbuffers/go"
+)
+type Uid struct {
+ _tab flatbuffers.Table
+}
+
+func GetRootAsUid(buf []byte, offset flatbuffers.UOffsetT) *Uid {
+ n := flatbuffers.GetUOffsetT(buf[offset:])
+ x := &Uid{}
+ x.Init(buf, n + offset)
+ return x
+}
+
+func (rcv *Uid) Init(buf []byte, i flatbuffers.UOffsetT) {
+ rcv._tab.Bytes = buf
+ rcv._tab.Pos = i
+}
+
+func (rcv *Uid) Id() []byte {
+ o := flatbuffers.UOffsetT(rcv._tab.Offset(4))
+ if o != 0 {
+ return rcv._tab.ByteVector(o + rcv._tab.Pos)
+ }
+ return nil
+}
+
+func (rcv *Uid) Name() []byte {
+ o := flatbuffers.UOffsetT(rcv._tab.Offset(6))
+ if o != 0 {
+ return rcv._tab.ByteVector(o + rcv._tab.Pos)
+ }
+ return nil
+}
+
+func UidStart(builder *flatbuffers.Builder) { builder.StartObject(2) }
+func UidAddId(builder *flatbuffers.Builder, id flatbuffers.UOffsetT) { builder.PrependUOffsetTSlot(0, flatbuffers.UOffsetT(id), 0) }
+func UidAddName(builder *flatbuffers.Builder, name flatbuffers.UOffsetT) { builder.PrependUOffsetTSlot(1, flatbuffers.UOffsetT(name), 0) }
+func UidEnd(builder *flatbuffers.Builder) flatbuffers.UOffsetT { return builder.EndObject() }
diff --git a/x/x.go b/x/x.go
new file mode 100644
index 00000000..3ea34bb2
--- /dev/null
+++ b/x/x.go
@@ -0,0 +1,60 @@
+package x
+
+import (
+ "encoding/json"
+ "fmt"
+ "net/http"
+
+ "github.com/Sirupsen/logrus"
+)
+
+const (
+ E_OK = "E_OK"
+ E_UNAUTHORIZED = "E_UNAUTHORIZED"
+ E_INVALID_METHOD = "E_INVALID_METHOD"
+ E_INVALID_REQUEST = "E_INVALID_REQUEST"
+ E_MISSING_REQUIRED = "E_MISSING_REQUIRED"
+ E_ERROR = "E_ERROR"
+ E_NODATA = "E_NODATA"
+ E_UPTODATE = "E_UPTODATE"
+ E_NOPERMISSION = "E_NOPERMISSION"
+
+ DUMMY_UUID = "00000000-0000-0000-0000-000000000000"
+)
+
+type Status struct {
+ Code string `json:"code"`
+ Message string `json:"message"`
+}
+
+func Err(entry *logrus.Entry, err error) *logrus.Entry {
+ return entry.WithField("error", err)
+}
+
+func SetStatus(w http.ResponseWriter, code, msg string) {
+ r := &Status{Code: code, Message: msg}
+ if js, err := json.Marshal(r); err == nil {
+ fmt.Fprint(w, string(js))
+ } else {
+ panic(fmt.Sprintf("Unable to marshal: %+v", r))
+ }
+}
+
+func Reply(w http.ResponseWriter, rep interface{}) {
+ if js, err := json.Marshal(rep); err == nil {
+ w.Header().Set("Content-Type", "application/json")
+ fmt.Fprint(w, string(js))
+ } else {
+ SetStatus(w, E_ERROR, "Internal server error")
+ }
+}
+
+func ParseRequest(w http.ResponseWriter, r *http.Request, data interface{}) bool {
+ defer r.Body.Close()
+ decoder := json.NewDecoder(r.Body)
+ if err := decoder.Decode(&data); err != nil {
+ SetStatus(w, E_ERROR, fmt.Sprintf("While parsing request: %v", err))
+ return false
+ }
+ return true
+}
--
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