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CVL Changes #6: Customized Xpath Engine integration (#27)
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Adding support for evaluating xpath expression (leafref, must, when expression) using customized open source xpath, xmlquery and jsonquery.
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dutta-partha authored Oct 19, 2020
1 parent 5e2466b commit 6f9535f
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Showing 7 changed files with 1,452 additions and 2 deletions.
18 changes: 18 additions & 0 deletions cvl/cvl.go
Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@ import (
log "github.com/golang/glog"
"github.com/go-redis/redis"
"github.com/antchfx/xmlquery"
"github.com/antchfx/xpath"
"github.com/antchfx/jsonquery"
"github.com/Azure/sonic-mgmt-common/cvl/internal/yparser"
. "github.com/Azure/sonic-mgmt-common/cvl/internal/util"
Expand Down Expand Up @@ -177,6 +178,15 @@ func init() {
SetTrace(true)
}

xpath.SetKeyGetClbk(func(listName string) []string {
if modelInfo.tableInfo[listName] != nil {
return modelInfo.tableInfo[listName].keys
}

return nil
})


ConfigFileSyncHandler()

cvlCfgMap := ReadConfFile()
Expand Down Expand Up @@ -214,6 +224,14 @@ func init() {
}

dbCacheSet(false, "PORT", 0)

xpath.SetLogCallback(func(fmt string, args ...interface{}) {
if !IsTraceLevelSet(TRACE_SEMANTIC) {
return
}

TRACE_LOG(INFO_API, TRACE_SEMANTIC, "XPATH: " + fmt, args...)
})
}

func Debug(on bool) {
Expand Down
92 changes: 92 additions & 0 deletions cvl/cvl_semantics.go
Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@ package cvl
import (
"strings"
"encoding/xml"
"encoding/json"
"github.com/antchfx/xmlquery"
"github.com/antchfx/jsonquery"
"github.com/Azure/sonic-mgmt-common/cvl/internal/yparser"
Expand Down Expand Up @@ -691,6 +692,97 @@ func (c *CVL) setOperation(op CVLOperation) {
}
}

//Add given YANG data buffer to Yang Validator
//redisKeys - Set of redis keys
//redisKeyFilter - Redis key filter in glob style pattern
//keyNames - Names of all keys separated by "|"
//predicate - Condition on keys/fields
//fields - Fields to retrieve, separated by "|"
//Return "," separated list of leaf nodes if only one leaf is requested
//One leaf is used as xpath query result in other nested xpath
func (c *CVL) addDepYangData(redisKeys []string, redisKeyFilter,
keyNames, predicate, fields, count string) string {

var v interface{}
tmpPredicate := ""

//Get filtered Redis data based on lua script
//filter derived from Xpath predicate
if (predicate != "") {
tmpPredicate = "return (" + predicate + ")"
}

cfgData, err := luaScripts["filter_entries"].Run(redisClient, []string{},
redisKeyFilter, keyNames, tmpPredicate, fields, count).Result()

singleLeaf := "" //leaf data for single leaf

TRACE_LOG(INFO_API, TRACE_SEMANTIC, "addDepYangData() with redisKeyFilter=%s, " +
"predicate=%s, fields=%s, returned cfgData = %s, err=%v",
redisKeyFilter, predicate, fields, cfgData, err)

if (cfgData == nil) {
return ""
}

//Parse the JSON map received from lua script
b := []byte(cfgData.(string))
if err := json.Unmarshal(b, &v); err != nil {
return ""
}

var dataMap map[string]interface{} = v.(map[string]interface{})

dataTop, _ := jsonquery.ParseJsonMap(&dataMap)

for jsonNode := dataTop.FirstChild; jsonNode != nil; jsonNode=jsonNode.NextSibling {
//Generate YANG data for Yang Validator from Redis JSON
topYangNode, _ := c.generateYangListData(jsonNode, false)

if topYangNode == nil {
continue
}

if (topYangNode.FirstChild != nil) &&
(topYangNode.FirstChild.FirstChild != nil) {
//Add attribute mentioning that data is from db
addAttrNode(topYangNode.FirstChild.FirstChild, "db", "")
}

//Build single leaf data requested
singleLeaf = ""
for redisKey := topYangNode.FirstChild.FirstChild;
redisKey != nil; redisKey = redisKey.NextSibling {

for field := redisKey.FirstChild; field != nil;
field = field.NextSibling {
if (field.Data == fields) {
//Single field requested
singleLeaf = singleLeaf + field.FirstChild.Data + ","
break
}
}
}

//Merge with main YANG data cache
doc := &xmlquery.Node{Type: xmlquery.DocumentNode}
doc.FirstChild = topYangNode
doc.LastChild = topYangNode
topYangNode.Parent = doc
if c.mergeYangData(c.yv.root, doc) != CVL_SUCCESS {
continue
}
}


//remove last comma in case mulitple values returned
if (singleLeaf != "") {
return singleLeaf[:len(singleLeaf) - 1]
}

return ""
}

//Check delete constraint for leafref if key/field is deleted
func (c *CVL) checkDeleteConstraint(cfgData []CVLEditConfigData,
tableName, keyVal, field string) CVLRetCode {
Expand Down
4 changes: 4 additions & 0 deletions cvl/internal/util/util.go
Original file line number Diff line number Diff line change
Expand Up @@ -133,6 +133,10 @@ func IsTraceSet() bool {
}
}

func IsTraceLevelSet(tracelevel CVLTraceLevel) bool {
return (cvlTraceFlags & (uint32)(tracelevel)) != 0
}

func TRACE_LEVEL_LOG(level log.Level, tracelevel CVLTraceLevel, fmtStr string, args ...interface{}) {

if (IsTraceSet() == false) {
Expand Down
2 changes: 2 additions & 0 deletions patches/apply.sh
Original file line number Diff line number Diff line change
Expand Up @@ -43,6 +43,8 @@ patch -d ${DEST_DIR}/github.com/openconfig -p1 < ${PATCH_DIR}/ygot/ygot.patch
patch -d ${DEST_DIR}/github.com/openconfig/goyang -p1 < ${PATCH_DIR}/goyang/goyang.patch

patch -d ${DEST_DIR}/github.com/antchfx/jsonquery -p1 < ${PATCH_DIR}/jsonquery.patch
patch -d ${DEST_DIR}/github.com/antchfx/xmlquery -p1 < ${PATCH_DIR}/xmlquery.patch
patch -d ${DEST_DIR}/github.com/antchfx/xpath -p1 < ${PATCH_DIR}/xpath.patch

patch -d ${DEST_DIR}/github.com/golang/glog -p1 < ${PATCH_DIR}/glog.patch

85 changes: 83 additions & 2 deletions patches/jsonquery.patch
Original file line number Diff line number Diff line change
@@ -1,8 +1,70 @@
diff --git a/node.go b/node.go
index 76032bb..db73a1e 100644
index 76032bb..f6103d9 100644
--- a/node.go
+++ b/node.go
@@ -155,3 +155,9 @@ func Parse(r io.Reader) (*Node, error) {
@@ -8,6 +8,7 @@ import (
"net/http"
"sort"
"strconv"
+ "strings"
)

// A NodeType is the type of a Node.
@@ -110,6 +111,29 @@ func parseValue(x interface{}, top *Node, level int) {
addNode(n)
parseValue(vv, n, level+1)
}
+ case map[string]string:
+ var keys []string
+ for key := range v {
+ keys = append(keys, key)
+ }
+ sort.Strings(keys)
+ for _, key := range keys {
+ tmpKey := key
+ var tmpVal interface{}
+ tmpVal = v[key]
+ if (strings.HasSuffix(key, "@")) {
+ tmpKey = key[:len(key) - 1]
+ tmpValArr := []interface{}{}
+ for _, val := range strings.Split(v[key], ",") {
+ tmpValArr = append(tmpValArr, val)
+ }
+ tmpVal = tmpValArr
+ }
+
+ n := &Node{Data: tmpKey, Type: ElementNode, level: level}
+ addNode(n)
+ parseValue(tmpVal, n, level+1)
+ }
case map[string]interface{}:
// The Go’s map iteration order is random.
// (https://blog.golang.org/go-maps-in-action#Iteration-order)
@@ -119,9 +143,21 @@ func parseValue(x interface{}, top *Node, level int) {
}
sort.Strings(keys)
for _, key := range keys {
- n := &Node{Data: key, Type: ElementNode, level: level}
+ tmpKey := key
+ var tmpVal interface{}
+ tmpVal = v[key]
+ if (strings.HasSuffix(key, "@")) {
+ tmpKey = key[:len(key) - 1]
+ tmpValArr := []interface{}{}
+ for _, val := range strings.Split(v[key].(string), ",") {
+ tmpValArr = append(tmpValArr, val)
+ }
+ tmpVal = tmpValArr
+ }
+
+ n := &Node{Data: tmpKey, Type: ElementNode, level: level}
addNode(n)
- parseValue(v[key], n, level+1)
+ parseValue(tmpVal, n, level+1)
}
case string:
n := &Node{Data: v, Type: TextNode, level: level}
@@ -155,3 +191,9 @@ func Parse(r io.Reader) (*Node, error) {
}
return parse(b)
}
Expand All @@ -12,3 +74,22 @@ index 76032bb..db73a1e 100644
+ parseValue(*jsonMap, doc, 1)
+ return doc, nil
+}
diff --git a/query.go b/query.go
index d105962..e8db1d6 100644
--- a/query.go
+++ b/query.go
@@ -120,6 +120,14 @@ func (a *NodeNavigator) MoveToRoot() {
a.cur = a.root
}

+func (a *NodeNavigator) MoveToContext() {
+ return
+}
+
+func (a *NodeNavigator) CurrentPrefix() string {
+ return ""
+}
+
func (a *NodeNavigator) MoveToParent() bool {
if n := a.cur.Parent; n != nil {
a.cur = n
94 changes: 94 additions & 0 deletions patches/xmlquery.patch
Original file line number Diff line number Diff line change
@@ -0,0 +1,94 @@
diff --git a/node.go b/node.go
index e86c0c3..028867c 100644
--- a/node.go
+++ b/node.go
@@ -48,7 +48,7 @@ type Node struct {

// InnerText returns the text between the start and end tags of the object.
func (n *Node) InnerText() string {
- var output func(*bytes.Buffer, *Node)
+ /*var output func(*bytes.Buffer, *Node)
output = func(buf *bytes.Buffer, n *Node) {
switch n.Type {
case TextNode:
@@ -64,7 +64,18 @@ func (n *Node) InnerText() string {

var buf bytes.Buffer
output(&buf, n)
- return buf.String()
+ return buf.String()*/
+
+ if (n.Type == TextNode) {
+ return n.Data
+ } else if (n.Type == ElementNode) &&
+ (n.FirstChild != nil) &&
+ (n.FirstChild.Type == TextNode) {
+ return n.FirstChild.Data
+ }
+
+
+ return ""
}

func (n *Node) sanitizedData(preserveSpaces bool) string {
diff --git a/query.go b/query.go
index 146c2a4..f21b61b 100644
--- a/query.go
+++ b/query.go
@@ -49,6 +49,29 @@ func CreateXPathNavigator(top *Node) *NodeNavigator {
return &NodeNavigator{curr: top, root: top, attr: -1}
}

+//Evaluate XPath expression, the expression should evaluate to true or false
+func Eval(top, ctx *Node, exp *xpath.Expr) bool {
+ if exp == nil {
+ return false
+ }
+
+ v := exp.Evaluate(&NodeNavigator{curr: ctx, ctxt: ctx, root: top, attr: -1})
+
+ switch val := v.(type) {
+ case bool:
+ return val
+ case string:
+ return (val != "")
+ case float64:
+ return (val != 0)
+ case *xpath.NodeIterator:
+ return (val != nil)
+ }
+
+ //return v.(bool)
+ return false
+}
+
func getCurrentNode(it *xpath.NodeIterator) *Node {
n := it.Current().(*NodeNavigator)
if n.NodeType() == xpath.AttributeNode {
@@ -145,7 +168,7 @@ func FindEachWithBreak(top *Node, expr string, cb func(int, *Node) bool) {
}

type NodeNavigator struct {
- root, curr *Node
+ root, curr, ctxt *Node
attr int
}

@@ -212,6 +235,17 @@ func (x *NodeNavigator) MoveToRoot() {
x.curr = x.root
}

+func (x *NodeNavigator) MoveToContext() {
+ x.curr = x.ctxt
+}
+
+func (x *NodeNavigator) CurrentPrefix() string {
+ if (x.ctxt != nil) {
+ return x.ctxt.Prefix
+ }
+ return ""
+}
+
func (x *NodeNavigator) MoveToParent() bool {
if x.attr != -1 {
x.attr = -1
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