Migrate JSONPath library

README.md

@@ -3,17 +3,15 @@ json_exporter
 [![CircleCI](https://circleci.com/gh/prometheus-community/json_exporter.svg?style=svg)](https://circleci.com/gh/prometheus-community/json_exporter)
 
 A [prometheus](https://prometheus.io/) exporter which scrapes remote JSON by JSONPath.
+For checking the JSONPath configuration supported by this exporter please head over [here](https://kubernetes.io/docs/reference/kubectl/jsonpath/).  
+Checkout the [examples](/examples) directory for sample exporter configuration, prometheus configuration and expected data format.  
 
-# Build
+#### :warning: The configuration syntax has changed in version `0.3.x`. If you are migrating from `0.2.x`, then please use the above mentioned JSONPath guide for correct configuration syntax.
 
-```sh
-make build
-```
+## Example Usage
 
-# Example Usage
-
-```sh
-$ cat example/data.json
+```console
+$ cat examples/data.json
 {
     "counter": 1234,
     "values": [
@@ -43,23 +41,23 @@ $ cat examples/config.yml
 ---
 metrics:
 - name: example_global_value
-  path: $.counter
+  path: "{ .counter }"
   help: Example of a top-level global value scrape in the json
   labels:
     environment: beta # static label
-    location: $.location          # dynamic label
+    location: "planet-{.location}"          # dynamic label
 
 - name: example_value
   type: object
   help: Example of sub-level value scrapes from a json
-  path: $.values[*]?(@.state == "ACTIVE")
+  path: '{.values[?(@.state == "ACTIVE")]}'
   labels:
     environment: beta # static label
-    id: $.id          # dynamic label
+    id: '{.id}'          # dynamic label
   values:
     active: 1      # static value
-    count: $.count # dynamic value
-    boolean: $.some_boolean
+    count: '{.count}' # dynamic value
+    boolean: '{.some_boolean}'
 
 headers:
   X-Dummy: my-test-header
@@ -70,7 +68,7 @@ Serving HTTP on 0.0.0.0 port 8000 ...
 $ ./json_exporter --config.file examples/config.yml &
 
 $ curl "http://localhost:7979/probe?target=http://localhost:8000/examples/data.json" | grep ^example
-example_global_value{environment="beta",location="mars"} 1234
+example_global_value{environment="beta",location="planet-mars"} 1234
 example_value_active{environment="beta",id="id-A"} 1
 example_value_active{environment="beta",id="id-C"} 1
 example_value_boolean{environment="beta",id="id-A"} 1
@@ -83,40 +81,22 @@ $ docker run --rm -it -p 9090:9090 -v $PWD/examples/prometheus.yml:/etc/promethe
 ```
 Then head over to http://localhost:9090/graph?g0.range_input=1h&g0.expr=example_value_active&g0.tab=1 or http://localhost:9090/targets to check the scraped metrics or the targets.
 
-# Exposing metrics through HTTPS
+## Exposing metrics through HTTPS
 
-web-config.yml
-```
-# Minimal TLS configuration example. Additionally, a certificate and a key file
-# are needed.
-tls_server_config:
-  cert_file: server.crt
-  key_file: server.key
-```
-Running
-```
-$ ./json_exporter --config.file examples/config.yml --web.config=web-config.yml &
+TLS configuration supported by this exporter can be found at [exporter-toolkit/web](https://github.com/prometheus/exporter-toolkit/blob/v0.5.1/docs/web-configuration.md)
 
-$ curl -k "https://localhost:7979/probe?target=http://localhost:8000/examples/data.json" | grep ^example
-example_global_value{environment="beta",location="mars"} 1234
-example_value_active{environment="beta",id="id-A"} 1
-example_value_active{environment="beta",id="id-C"} 1
-example_value_boolean{environment="beta",id="id-A"} 1
-example_value_boolean{environment="beta",id="id-C"} 0
-example_value_count{environment="beta",id="id-A"} 1
-example_value_count{environment="beta",id="id-C"} 3
+## Build
+
+```sh
+make build
 ```
-For futher information about TLS configuration, please visit: [exporter-toolkit/https](https://github.com/prometheus/exporter-toolkit/blob/v0.1.0/https/README.md)
 
-# Docker
+## Docker
 
 ```console
 docker run \
-  -v $PWD/examples/config.yml:/config.yml
+  -v $PWD/examples/config.yml:/config.yml \
   quay.io/prometheuscommunity/json-exporter \
-    --config.file /config.yml
+  --config.file=/config.yml
 ```
 
-# See Also
-- [kawamuray/jsonpath](https://github.com/kawamuray/jsonpath#path-syntax) : For syntax reference of JSONPath.
-  Originally forked from nicksardo/jsonpath(now is https://github.com/NodePrime/jsonpath).

cmd/main.go

@@ -28,7 +28,7 @@ import (
 	"github.com/prometheus/common/promlog"
 	"github.com/prometheus/common/promlog/flag"
 	"github.com/prometheus/common/version"
-	"github.com/prometheus/exporter-toolkit/https"
+	"github.com/prometheus/exporter-toolkit/web"
 	"gopkg.in/alecthomas/kingpin.v2"
 )
 
@@ -74,7 +74,7 @@ func Run() {
 	})
 
 	server := &http.Server{Addr: *listenAddress}
-	if err := https.Listen(server, *tlsConfigFile, logger); err != nil {
+	if err := web.ListenAndServe(server, *tlsConfigFile, logger); err != nil {
 		level.Error(logger).Log("msg", "Failed to start the server", "err", err) //nolint:errcheck
 		os.Exit(1)
 	}

examples/config.yml

@@ -1,23 +1,23 @@
 ---
 metrics:
 - name: example_global_value
-  path: $.counter
+  path: "{ .counter }"
   help: Example of a top-level global value scrape in the json
   labels:
     environment: beta # static label
-    location: $.location          # dynamic label
+    location: "planet-{.location}"          # dynamic label
 
 - name: example_value
   type: object
   help: Example of sub-level value scrapes from a json
-  path: $.values[*]?(@.state == "ACTIVE")
+  path: '{.values[?(@.state == "ACTIVE")]}'
   labels:
     environment: beta # static label
-    id: $.id          # dynamic label
+    id: '{.id}'          # dynamic label
   values:
     active: 1      # static value
-    count: $.count # dynamic value
-    boolean: $.some_boolean
+    count: '{.count}' # dynamic value
+    boolean: '{.some_boolean}'
 
 headers:
   X-Dummy: my-test-header

exporter/collector.go

@@ -14,13 +14,13 @@
 package exporter
 
 import (
-	"errors"
-	"strconv"
+	"bytes"
+	"encoding/json"
 
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
-	"github.com/kawamuray/jsonpath" // Originally: "github.com/NickSardo/jsonpath"
 	"github.com/prometheus/client_golang/prometheus"
+	"k8s.io/client-go/util/jsonpath"
 )
 
 type JsonMetricCollector struct {
@@ -45,140 +45,106 @@ func (mc JsonMetricCollector) Describe(ch chan<- *prometheus.Desc) {
 func (mc JsonMetricCollector) Collect(ch chan<- prometheus.Metric) {
 	for _, m := range mc.JsonMetrics {
 		if m.ValueJsonPath == "" { // ScrapeType is 'value'
-			floatValue, err := extractValue(mc.Logger, mc.Data, m.KeyJsonPath)
+			value, err := extractValue(mc.Logger, mc.Data, m.KeyJsonPath, false)
 			if err != nil {
-				// Avoid noise and continue silently if it was a missing path error
-				if err.Error() == "Path not found" {
-					level.Debug(mc.Logger).Log("msg", "Failed to extract float value for metric", "path", m.KeyJsonPath, "err", err, "metric", m.Desc) //nolint:errcheck
-					continue
-				}
-				level.Error(mc.Logger).Log("msg", "Failed to extract float value for metric", "path", m.KeyJsonPath, "err", err, "metric", m.Desc) //nolint:errcheck
+				level.Error(mc.Logger).Log("msg", "Failed to extract value for metric", "path", m.KeyJsonPath, "err", err, "metric", m.Desc) //nolint:errcheck
 				continue
 			}
 
-			ch <- prometheus.MustNewConstMetric(
-				m.Desc,
-				prometheus.UntypedValue,
-				floatValue,
-				extractLabels(mc.Logger, mc.Data, m.LabelsJsonPaths)...,
-			)
-		} else { // ScrapeType is 'object'
-			path, err := compilePath(m.KeyJsonPath)
-			if err != nil {
-				level.Error(mc.Logger).Log("msg", "Failed to compile path", "path", m.KeyJsonPath, "err", err) //nolint:errcheck
+			if floatValue, err := SanitizeValue(value); err == nil {
+
+				ch <- prometheus.MustNewConstMetric(
+					m.Desc,
+					prometheus.UntypedValue,
+					floatValue,
+					extractLabels(mc.Logger, mc.Data, m.LabelsJsonPaths)...,
+				)
+			} else {
+				level.Error(mc.Logger).Log("msg", "Failed to convert extracted value to float64", "path", m.KeyJsonPath, "value", value, "err", err, "metric", m.Desc) //nolint:errcheck
 				continue
 			}
-
-			eval, err := jsonpath.EvalPathsInBytes(mc.Data, []*jsonpath.Path{path})
+		} else { // ScrapeType is 'object'
+			values, err := extractValue(mc.Logger, mc.Data, m.KeyJsonPath, true)
 			if err != nil {
-				level.Error(mc.Logger).Log("msg", "Failed to create evaluator for json path", "path", m.KeyJsonPath, "err", err) //nolint:errcheck
+				level.Error(mc.Logger).Log("msg", "Failed to extract json objects for metric", "err", err, "metric", m.Desc) //nolint:errcheck
 				continue
 			}
-			for {
-				if result, ok := eval.Next(); ok {
-					floatValue, err := extractValue(mc.Logger, result.Value, m.ValueJsonPath)
+
+			var jsonData []interface{}
+			if err := json.Unmarshal([]byte(values), &jsonData); err == nil {
+				for _, data := range jsonData {
+					jdata, err := json.Marshal(data)
 					if err != nil {
-						level.Error(mc.Logger).Log("msg", "Failed to extract value", "path", m.ValueJsonPath, "err", err) //nolint:errcheck
+						level.Error(mc.Logger).Log("msg", "Failed to marshal data to json", "path", m.ValueJsonPath, "err", err, "metric", m.Desc, "data", data) //nolint:errcheck
+						continue
+					}
+					value, err := extractValue(mc.Logger, jdata, m.ValueJsonPath, false)
+					if err != nil {
+						level.Error(mc.Logger).Log("msg", "Failed to extract value for metric", "path", m.ValueJsonPath, "err", err, "metric", m.Desc) //nolint:errcheck
 						continue
 					}
 
-					ch <- prometheus.MustNewConstMetric(
-						m.Desc,
-						prometheus.UntypedValue,
-						floatValue,
-						extractLabels(mc.Logger, result.Value, m.LabelsJsonPaths)...,
-					)
-				} else {
-					break
+					if floatValue, err := SanitizeValue(value); err == nil {
+						ch <- prometheus.MustNewConstMetric(
+							m.Desc,
+							prometheus.UntypedValue,
+							floatValue,
+							extractLabels(mc.Logger, jdata, m.LabelsJsonPaths)...,
+						)
+					} else {
+						level.Error(mc.Logger).Log("msg", "Failed to convert extracted value to float64", "path", m.ValueJsonPath, "value", value, "err", err, "metric", m.Desc) //nolint:errcheck
+						continue
+					}
 				}
+			} else {
+				level.Error(mc.Logger).Log("msg", "Failed to convert extracted objects to json", "err", err, "metric", m.Desc) //nolint:errcheck
+				continue
 			}
 		}
 	}
 }
 
-func compilePath(path string) (*jsonpath.Path, error) {
-	// All paths in this package is for extracting a value.
-	// Complete trailing '+' sign if necessary.
-	if path[len(path)-1] != '+' {
-		path += "+"
-	}
+// Returns the last matching value at the given json path
+func extractValue(logger log.Logger, data []byte, path string, enableJSONOutput bool) (string, error) {
+	var jsonData interface{}
+	buf := new(bytes.Buffer)
 
-	paths, err := jsonpath.ParsePaths(path)
-	if err != nil {
-		return nil, err
+	j := jsonpath.New("jp")
+	if enableJSONOutput {
+		j.EnableJSONOutput(true)
 	}
-	return paths[0], nil
-}
 
-// Returns the first matching float value at the given json path
-func extractValue(logger log.Logger, json []byte, path string) (float64, error) {
-	var floatValue = -1.0
-	var result *jsonpath.Result
-	var err error
-
-	if len(path) < 1 || path[0] != '$' {
-		// Static value
-		return parseValue([]byte(path))
+	if err := json.Unmarshal(data, &jsonData); err != nil {
+		level.Error(logger).Log("msg", "Failed to unmarshal data to json", "err", err, "data", data) //nolint:errcheck
+		return "", err
 	}
 
-	// Dynamic value
-	p, err := compilePath(path)
-	if err != nil {
-		return floatValue, err
+	if err := j.Parse(path); err != nil {
+		level.Error(logger).Log("msg", "Failed to parse jsonpath", "err", err, "path", path, "data", data) //nolint:errcheck
+		return "", err
 	}
 
-	eval, err := jsonpath.EvalPathsInBytes(json, []*jsonpath.Path{p})
-	if err != nil {
-		return floatValue, err
+	if err := j.Execute(buf, jsonData); err != nil {
+		level.Error(logger).Log("msg", "Failed to execute jsonpath", "err", err, "path", path, "data", data) //nolint:errcheck
+		return "", err
 	}
 
-	result, ok := eval.Next()
-	if result == nil || !ok {
-		if eval.Error != nil {
-			return floatValue, eval.Error
-		} else {
-			level.Debug(logger).Log("msg", "Path not found", "path", path, "json", string(json)) //nolint:errcheck
-			return floatValue, errors.New("Path not found")
-		}
+	// Since we are finally going to extract only float64, unquote if necessary
+	if res, err := jsonpath.UnquoteExtend(buf.String()); err == nil {
+		return res, nil
 	}
 
-	return SanitizeValue(result)
+	return buf.String(), nil
 }
 
 // Returns the list of labels created from the list of provided json paths
-func extractLabels(logger log.Logger, json []byte, paths []string) []string {
+func extractLabels(logger log.Logger, data []byte, paths []string) []string {
 	labels := make([]string, len(paths))
 	for i, path := range paths {
-
-		// Dynamic value
-		p, err := compilePath(path)
-		if err != nil {
-			level.Error(logger).Log("msg", "Failed to compile path for label", "path", path, "err", err) //nolint:errcheck
-			continue
-		}
-
-		eval, err := jsonpath.EvalPathsInBytes(json, []*jsonpath.Path{p})
-		if err != nil {
-			level.Error(logger).Log("msg", "Failed to create evaluator for json", "path", path, "err", err) //nolint:errcheck
-			continue
-		}
-
-		result, ok := eval.Next()
-		if result == nil || !ok {
-			if eval.Error != nil {
-				level.Error(logger).Log("msg", "Failed to evaluate", "json", string(json), "err", eval.Error) //nolint:errcheck
-			} else {
-				level.Warn(logger).Log("msg", "Label path not found in json", "path", path)                        //nolint:errcheck
-				level.Debug(logger).Log("msg", "Label path not found in json", "path", path, "json", string(json)) //nolint:errcheck
-			}
-			continue
-		}
-
-		l, err := strconv.Unquote(string(result.Value))
-		if err == nil {
-			labels[i] = l
+		if result, err := extractValue(logger, data, path, false); err == nil {
+			labels[i] = result
 		} else {
-			labels[i] = string(result.Value)
+			level.Error(logger).Log("msg", "Failed to extract label value", "err", err, "path", path, "data", data) //nolint:errcheck
 		}
 	}
 	return labels