From 1489cfc7da74dafd23c36030afce2846e7fa2e60 Mon Sep 17 00:00:00 2001
From: Rahul <rahul.gupta@netapp.com>
Date: Tue, 26 Sep 2023 21:58:21 +0530
Subject: [PATCH] perf: Zapi allocs improvements (#2380)

* perf: Zapi allocs improvements

* perf: Zapi allocs improvements
---
 cmd/collectors/sensor_test.go |  2 +-
 pkg/api/ontapi/zapi/client.go | 22 +++++++++++-----------
 pkg/tree/tree.go              | 12 ++++++++----
 pkg/tree/xml/xml.go           | 18 +++++++++++++-----
 4 files changed, 33 insertions(+), 21 deletions(-)

diff --git a/cmd/collectors/sensor_test.go b/cmd/collectors/sensor_test.go
index 6dd70c09d..6424bcac1 100644
--- a/cmd/collectors/sensor_test.go
+++ b/cmd/collectors/sensor_test.go
@@ -27,7 +27,7 @@ func loadTestdata() {
 	// setup matrix data
 	var err error
 	var fetch func(*matrix.Instance, *node.Node, []string)
-	dat, err := os.ReadFile(testxml)
+	dat, err := os.Open(testxml)
 	if err != nil {
 		abs, _ := filepath.Abs(testxml)
 		fmt.Printf("failed to load %s\n", abs)
diff --git a/pkg/api/ontapi/zapi/client.go b/pkg/api/ontapi/zapi/client.go
index 5e6ab2166..3af08869a 100644
--- a/pkg/api/ontapi/zapi/client.go
+++ b/pkg/api/ontapi/zapi/client.go
@@ -16,6 +16,7 @@ import (
 	"github.com/netapp/harvest/v2/pkg/requests"
 	"github.com/netapp/harvest/v2/pkg/tree"
 	"github.com/netapp/harvest/v2/pkg/tree/node"
+	"github.com/netapp/harvest/v2/pkg/tree/xml"
 	"io"
 	"net/http"
 	"strconv"
@@ -496,23 +497,22 @@ func (c *Client) invoke(withTimers bool) (*node.Node, time.Duration, time.Durati
 		return result, responseT, parseT, errs.New(errs.ErrAPIResponse, response.Status, errs.WithStatus(response.StatusCode))
 	}
 
-	// read response body
-	if body, err = io.ReadAll(response.Body); err != nil {
-		return result, responseT, parseT, err
-	}
-	defer c.printRequestAndResponse(zapiReq, body)
-
 	// parse xml
 	if withTimers {
 		start = time.Now()
 	}
-	if root, err = tree.LoadXML(body); err != nil {
+	if root, body, err = xml.Load(response.Body, c.logZapi); err != nil {
 		return result, responseT, parseT, err
 	}
 	if withTimers {
 		parseT = time.Since(start)
 	}
 
+	// read response body
+	if c.logZapi {
+		defer c.printRequestAndResponse(zapiReq, body)
+	}
+
 	// check if the request was successful
 	if result = root.GetChildS("results"); result == nil {
 		return result, responseT, parseT, errs.New(errs.ErrAPIResponse, "missing \"results\"")
@@ -551,11 +551,11 @@ func (c *Client) TraceLogSet(collectorName string, config *node.Node) {
 }
 
 func (c *Client) printRequestAndResponse(req string, response []byte) {
-	res := "<nil>"
-	if response != nil {
-		res = string(response)
-	}
 	if req != "" {
+		res := "<nil>"
+		if response != nil {
+			res = string(response)
+		}
 		c.Logger.Info().
 			Str("Request", req).
 			Str("Response", res).
diff --git a/pkg/tree/tree.go b/pkg/tree/tree.go
index ef6314852..692a2eb91 100644
--- a/pkg/tree/tree.go
+++ b/pkg/tree/tree.go
@@ -9,6 +9,7 @@ import (
 	"github.com/netapp/harvest/v2/pkg/tree/node"
 	"github.com/netapp/harvest/v2/pkg/tree/xml"
 	y3 "gopkg.in/yaml.v3"
+	"io"
 	"os"
 )
 
@@ -67,8 +68,9 @@ func consume(r *node.Node, key string, y *y3.Node, makeNewChild bool) {
 	}
 }
 
-func LoadXML(data []byte) (*node.Node, error) {
-	return xml.Load(data)
+func LoadXML(r io.Reader) (*node.Node, error) {
+	root, _, err := xml.Load(r, false)
+	return root, err
 }
 
 func DumpXML(n *node.Node) ([]byte, error) {
@@ -76,9 +78,11 @@ func DumpXML(n *node.Node) ([]byte, error) {
 }
 
 func ImportXML(filepath string) (*node.Node, error) {
-	data, err := os.ReadFile(filepath)
+	file, err := os.Open(filepath)
 	if err != nil {
 		return nil, err
 	}
-	return LoadXML(data)
+	//goland:noinspection GoUnhandledErrorResult
+	defer file.Close()
+	return LoadXML(file)
 }
diff --git a/pkg/tree/xml/xml.go b/pkg/tree/xml/xml.go
index a213cd758..0941bc67e 100644
--- a/pkg/tree/xml/xml.go
+++ b/pkg/tree/xml/xml.go
@@ -8,16 +8,24 @@ import (
 	"bytes"
 	"encoding/xml"
 	"github.com/netapp/harvest/v2/pkg/tree/node"
+	"io"
 )
 
-func Load(data []byte) (*node.Node, error) {
+func Load(data io.Reader, log bool) (*node.Node, []byte, error) {
+	var buf bytes.Buffer
+	reader := data
+
+	if log {
+		reader = io.TeeReader(data, &buf)
+	}
+
 	root := new(node.Node)
-	buf := bytes.NewBuffer(data)
-	dec := xml.NewDecoder(buf)
+	dec := xml.NewDecoder(reader)
 	if err := dec.Decode(&root); err != nil {
-		return nil, err
+		return nil, nil, err
 	}
-	return root, nil
+
+	return root, buf.Bytes(), nil
 }
 
 func Dump(n *node.Node) ([]byte, error) {