go/mio: add example REST API server

Add example of REST API server based on go bindings.

Signed-off-by: kiwionly2 <gheewooi.ong@seagate.com>

bindings/go/go_motr_api_server/README.md

@@ -0,0 +1,67 @@
+
+## Motr REST API server
+
+Motr REST API Server is a simple REST API Server which based on motr go bindings. 
+
+It included a REST API server and a http client.
+
+The API implemented as below:
+
+```
+/api/kv/put
+/api/kv/get
+/api/kv/delete
+/api/object/read
+/api/object/write
+```
+
+#### Server
+
+To start REST API server, first you need to run motr server.
+
+Follow motr [quick start guide](/doc/Quick-Start-Guide.rst) to build motr.
+
+To start motr in development mode, open a new terminal, go to `%cortx_motr_dir%/motr/examples` at `motr` root directory.
+
+```sh
+cd %cortx_home%/motr/examples
+./setup_a_running_motr_system.sh
+```
+
+After motr server start, you should see the connection information at the end of terminal.
+
+At this directory, open `motr.toml`, this is where `motr` connection configure, modify the value accordingly and save the file.
+
+Open another terminal and run the REST API server :
+```
+> go mod tidy
+> export MOTR_HOME=motr_root_diretory
+> CGO_CFLAGS="-I/$MOTR_HOME -I/usr/include/motr -DM0_EXTERN=extern -DM0_INTERNAL= -Wno-attributes" CGO_LDFLAGS="-L$MOTR_HOME/motr/.libs -Wl,-rpath=$MOTR_HOME/motr/.libs -lmotr" go run .
+```
+
+You should see the server start and running at port `8081`.
+
+
+#### Client
+
+To interect with the REST API server, you could use http client under `http_client` folder:
+
+```go
+client := NewClient("localhost", 8081)
+
+// read from file and write to motr
+response, err := client.Write(IndexID, "black_hole.png")
+
+// read from motr and write to file
+err := client.Read(IndexID, objectSize, "out.png")
+```
+
+Open another terminal and run the tests to see if the http client work as expected.
+```
+> cd http_client
+> go test -v 
+```
+
+You could refer to test cases for more sample of client usage.
+
+

bindings/go/go_motr_api_server/api/api_common.go

@@ -0,0 +1,108 @@
+package api
+
+import (
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net/url"
+	"strconv"
+	"time"
+
+	"github.com/gin-gonic/gin"
+)
+
+func get(ctx *gin.Context, name string, required bool, defaultValue interface{}, errs *[]error) interface{} {
+
+	var val string
+
+	if ctx.Request.Method == "POST" {
+		val = ctx.PostForm(name)
+
+		// if POST binary content, get from query
+		if val == "" {
+			val = ctx.Query(name)
+		}
+
+	} else {
+		val = ctx.Query(name)
+	}
+
+	if required && val == "" {
+		toError(errs, name+" is required")
+		return defaultValue
+	} else if val == "" {
+		return defaultValue
+	}
+
+	val, err := url.QueryUnescape(val)
+
+	if err != nil {
+		toError(errs, err.Error())
+	}
+
+	return val
+}
+
+func getString(ctx *gin.Context, name string, required bool, defaultValue interface{}, errs *[]error) string {
+	val := get(ctx, name, required, defaultValue, errs)
+	return toString(val)
+}
+
+func getInt(ctx *gin.Context, name string, required bool, defaultValue interface{}, errs *[]error) int {
+	val := get(ctx, name, required, defaultValue, errs)
+	c := toI32(val)
+	return int(c)
+}
+
+func getBytes(ctx *gin.Context, errs *[]error) []byte {
+	ByteBody, err := ioutil.ReadAll(ctx.Request.Body)
+
+	if err != nil {
+		toError(errs, err.Error())
+		return nil
+	}
+
+	return ByteBody
+}
+
+func toError(errs *[]error, msg string) {
+	*errs = append(*errs, errors.New(msg))
+}
+
+func hasError(errs []error) error {
+
+	for _, err := range errs {
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func createError(err error) map[string]interface{} {
+
+	errs := make(map[string]interface{})
+	errs["error"] = err.Error()
+
+	return errs
+}
+
+func toTime(end time.Duration) string {
+	return fmt.Sprintf("%v", end)
+}
+
+func toString(t interface{}) string {
+	return fmt.Sprintf("%+v", t)
+}
+
+func toI32(t interface{}) int32 {
+	s := toString(t)
+	i, err := strconv.Atoi(s)
+
+	if err != nil {
+		return 0
+	}
+
+	return int32(i)
+}

bindings/go/go_motr_api_server/api/kv_api.go

@@ -0,0 +1,125 @@
+package api
+
+import (
+	"fmt"
+	"go_motr_api_server/v2/motr"
+	"net/http"
+	"time"
+
+	"github.com/gin-gonic/gin"
+)
+
+func Status(ctx *gin.Context) {
+
+	json := make(map[string]interface{})
+	json["status"] = "ok"
+
+	ctx.JSON(http.StatusOK, json)
+}
+
+func GetKey(ctx *gin.Context) {
+
+	start := time.Now()
+
+	errs := &[]error{}
+
+	indexID := getString(ctx, "index_id", true, nil, errs)
+	key := getString(ctx, "key", true, nil, errs)
+
+	if err := hasError(*errs); err != nil {
+		ctx.AbortWithStatusJSON(http.StatusBadRequest, createError(err))
+		return
+	}
+
+	value, err := motr.Get(indexID, key)
+
+	if err != nil {
+		ctx.AbortWithStatusJSON(http.StatusBadRequest, createError(err))
+		return
+	}
+
+	end := time.Since(start)
+
+	meta := make(map[string]interface{})
+	meta["time"] = toTime(end)
+
+	json := make(map[string]interface{})
+	json["meta"] = meta
+	json["index_id"] = indexID
+	json["key"] = key
+	json["value"] = value
+
+	ctx.JSON(http.StatusOK, json)
+}
+
+func DeleteKey(ctx *gin.Context) {
+
+	start := time.Now()
+
+	errs := &[]error{}
+
+	indexID := getString(ctx, "index_id", true, nil, errs)
+	key := getString(ctx, "key", true, nil, errs)
+
+	if err := hasError(*errs); err != nil {
+		ctx.AbortWithStatusJSON(http.StatusBadRequest, createError(err))
+		return
+	}
+
+	err := motr.Delete(indexID, key)
+
+	if err != nil {
+		ctx.AbortWithStatusJSON(http.StatusBadRequest, createError(err))
+		return
+	}
+
+	end := time.Since(start)
+
+	meta := make(map[string]interface{})
+	meta["time"] = toTime(end)
+
+	json := make(map[string]interface{})
+	json["meta"] = meta
+	json["index_id"] = indexID
+	json["key"] = key
+
+	ctx.JSON(http.StatusOK, json)
+}
+
+func PutKeyValue(ctx *gin.Context) {
+
+	start := time.Now()
+
+	errs := &[]error{}
+
+	indexID := getString(ctx, "index_id", true, nil, errs)
+	key := getString(ctx, "key", true, nil, errs)
+	value := getString(ctx, "value", true, nil, errs)
+
+	if err := hasError(*errs); err != nil {
+		ctx.AbortWithStatusJSON(http.StatusBadRequest, createError(err))
+		return
+	}
+
+	fmt.Println(indexID, key, value)
+
+	err := motr.Put(indexID, key, value)
+
+	if err != nil {
+		ctx.AbortWithStatusJSON(http.StatusBadRequest, createError(err))
+		return
+	}
+
+	end := time.Since(start)
+
+	meta := make(map[string]interface{})
+	meta["time"] = toTime(end)
+
+	json := make(map[string]interface{})
+	json["meta"] = meta
+	json["index_id"] = indexID
+	json["key"] = key
+	json["value"] = value
+
+	ctx.JSON(http.StatusOK, json)
+}

bindings/go/go_motr_api_server/api/object_api.go

@@ -0,0 +1,72 @@
+package api
+
+import (
+	"bytes"
+	"go_motr_api_server/v2/motr"
+	"net/http"
+	"time"
+
+	"github.com/gin-gonic/gin"
+)
+
+func Write(ctx *gin.Context) {
+
+	start := time.Now()
+
+	errs := &[]error{}
+
+	indexID := getString(ctx, "index_id", true, nil, errs)
+	size := getInt(ctx, "size", true, nil, errs)
+	byteBody := getBytes(ctx, errs)
+
+	if err := hasError(*errs); err != nil {
+		ctx.AbortWithStatusJSON(http.StatusBadRequest, createError(err))
+		return
+	}
+
+	err := motr.Write("", indexID, uint64(size), bytes.NewReader(byteBody))
+
+	if err != nil {
+		ctx.AbortWithStatusJSON(http.StatusBadRequest, createError(err))
+		return
+	}
+
+	end := time.Since(start)
+
+	meta := make(map[string]interface{})
+	meta["time"] = toTime(end)
+
+	json := make(map[string]interface{})
+	json["meta"] = meta
+	json["indexID"] = indexID
+	json["size"] = size
+
+	ctx.JSON(http.StatusOK, json)
+}
+
+func Read(ctx *gin.Context) {
+
+	start := time.Now()
+
+	errs := &[]error{}
+
+	indexID := getString(ctx, "index_id", true, nil, errs)
+	size := getInt(ctx, "size", true, nil, errs)
+
+	if err := hasError(*errs); err != nil {
+		ctx.AbortWithStatusJSON(http.StatusBadRequest, createError(err))
+		return
+	}
+
+	byteContent, err := motr.Read("", indexID, uint64(size))
+
+	if err != nil {
+		ctx.AbortWithStatusJSON(http.StatusBadRequest, createError(err))
+		return
+	}
+
+	end := time.Since(start)
+
+	ctx.Header("time", toTime(end))
+	ctx.Data(http.StatusOK, "application/octet-stream", byteContent)
+}