chore: Custom expression functions (#37)

expr/function.go

@@ -0,0 +1,108 @@
+package expr
+
+import (
+	"encoding/json"
+	"fmt"
+	"reflect"
+	"strconv"
+
+	"github.com/oliveagle/jsonpath"
+)
+
+func GetExprEnvFunctionMap() map[string]interface{} {
+	return map[string]interface{}{
+		"asInt":    AsInt,
+		"asFloat":  AsFloat,
+		"string":   AsStr,
+		"jsonpath": JsonPath,
+	}
+}
+
+func AsStr(val interface{}) interface{} {
+	return fmt.Sprintf("%v", val)
+}
+
+func JsonPath(jsonStr string, path string) interface{} {
+	var jsonMap interface{}
+	err := json.Unmarshal([]byte(jsonStr), &jsonMap)
+	if err != nil {
+		panic(err)
+	}
+	value, err := jsonpath.JsonPathLookup(jsonMap, path)
+	if err != nil {
+		panic(err)
+	}
+	return value
+}
+
+func AsInt(in interface{}) int64 {
+	switch i := in.(type) {
+	case float64:
+		return int64(i)
+	case float32:
+		return int64(i)
+	case int64:
+		return i
+	case int32:
+		return int64(i)
+	case int16:
+		return int64(i)
+	case int8:
+		return int64(i)
+	case int:
+		return int64(i)
+	case uint64:
+		return int64(i)
+	case uint32:
+		return int64(i)
+	case uint16:
+		return int64(i)
+	case uint8:
+		return int64(i)
+	case uint:
+		return int64(i)
+	case string:
+		inAsInt, err := strconv.ParseInt(i, 10, 64)
+		if err == nil {
+			return inAsInt
+		}
+		panic(err)
+	}
+	panic(fmt.Sprintf("asInt() not supported on %v %v", reflect.TypeOf(in), in))
+}
+
+func AsFloat(in interface{}) float64 {
+	switch i := in.(type) {
+	case float64:
+		return i
+	case float32:
+		return float64(i)
+	case int64:
+		return float64(i)
+	case int32:
+		return float64(i)
+	case int16:
+		return float64(i)
+	case int8:
+		return float64(i)
+	case int:
+		return float64(i)
+	case uint64:
+		return float64(i)
+	case uint32:
+		return float64(i)
+	case uint16:
+		return float64(i)
+	case uint8:
+		return float64(i)
+	case uint:
+		return float64(i)
+	case string:
+		inAsFloat, err := strconv.ParseFloat(i, 64)
+		if err == nil {
+			return inAsFloat
+		}
+		panic(err)
+	}
+	panic(fmt.Sprintf("asFloat() not supported on %v %v", reflect.TypeOf(in), in))
+}

expr/function_test.go

@@ -0,0 +1,31 @@
+package expr
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestAsFloat(t *testing.T) {
+	assert.Equal(t, int64(1), AsInt(int32(1)))
+	assert.Equal(t, int64(1), AsInt(int64(1)))
+	assert.Equal(t, int64(1), AsInt("1"))
+	assert.Panics(t, func() { AsInt("1.56") })
+}
+
+func TestAsFloat2(t *testing.T) {
+	assert.Equal(t, 1.24, AsFloat(1.24))
+	assert.Equal(t, 1.65, AsFloat("1.65"))
+}
+
+func TestAsStr(t *testing.T) {
+	assert.Equal(t, "1.24", AsStr(1.24))
+	assert.Equal(t, "1", AsStr(1))
+}
+
+func TestJsonPath(t *testing.T) {
+	simpleJson := "{\"employee\":{\"name\":\"sonoo\",\"salary\":56000,\"married\":true}}"
+	arrayJson := "{\"employees\":[{\"name\":\"Shyam\",\"email\":\"[email protected]\"},{\"name\":\"Bob\",\"email\":\"[email protected]\"}," +
+		"{\"name\":\"Jai\",\"email\":\"[email protected]\"}]}"
+	assert.Equal(t, "sonoo", JsonPath(simpleJson, "$.employee.name"))
+	assert.Equal(t, "Bob", JsonPath(arrayJson, "$.employees[1].name"))
+}

go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/golang/protobuf v1.3.3
 	github.com/grpc-ecosystem/grpc-gateway v1.14.6
 	github.com/minio/minio-go/v7 v7.0.2
+	github.com/oliveagle/jsonpath v0.0.0-20180606110733-2e52cf6e6852
 	github.com/pkg/errors v0.9.1
 	github.com/sirupsen/logrus v1.6.0
 	github.com/smartystreets/goconvey v1.6.4 // indirect

go.sum

@@ -159,6 +159,8 @@ github.com/munnerz/goautoneg v0.0.0-20120707110453-a547fc61f48d/go.mod h1:+n7T8m
 github.com/mwitkow/go-conntrack v0.0.0-20161129095857-cc309e4a2223/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
 github.com/mxk/go-flowrate v0.0.0-20140419014527-cca7078d478f/go.mod h1:ZdcZmHo+o7JKHSa8/e818NopupXU1YMK5fe1lsApnBw=
 github.com/oklog/ulid v1.3.1/go.mod h1:CirwcVhetQ6Lv90oh/F+FBtV6XMibvdAFo93nm5qn4U=
+github.com/oliveagle/jsonpath v0.0.0-20180606110733-2e52cf6e6852 h1:Yl0tPBa8QPjGmesFh1D0rDy+q1Twx6FyU7VWHi8wZbI=
+github.com/oliveagle/jsonpath v0.0.0-20180606110733-2e52cf6e6852/go.mod h1:eqOVx5Vwu4gd2mmMZvVZsgIqNSaW3xxRThUJ0k/TPk4=
 github.com/onsi/ginkgo v0.0.0-20170829012221-11459a886d9c/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
 github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
 github.com/onsi/ginkgo v1.10.1/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=