matched fields

Author: cmaster11

.gitattributes

@@ -0,0 +1 @@
+* text eol=lf

config.go

@@ -2,8 +2,9 @@ package k8seventwatcher
 
 import (
 	"errors"
-	"gopkg.in/yaml.v2"
 	"log"
+
+	"gopkg.in/yaml.v2"
 )
 
 type Config struct {
@@ -27,18 +28,18 @@ func (c *Config) Validate() error {
 	return nil
 }
 
-func (c *Config) MatchingEventFilter(event map[string]interface{}) (*EventFilter, error) {
+func (c *Config) MatchingEventFilter(event map[string]interface{}) (*EventFilter, map[string]interface{}, error) {
 	for _, filter := range c.Filters {
-		matches, err := filter.Matches(event)
+		matchedFields, err := filter.Matches(event)
 		if err != nil {
-			return nil, errorf("error matching filter: %s", err)
+			return nil, nil, errorf("error matching filter: %s", err)
 		}
-		if matches {
-			return filter, nil
+		if matchedFields != nil {
+			return filter, matchedFields, nil
 		}
 	}
 
-	return nil, nil
+	return nil, nil, nil
 }
 
 func (c *Config) Dump() string {

example/main.go

@@ -4,11 +4,12 @@ import (
 	"bufio"
 	"flag"
 	"fmt"
+	"log"
+	"os"
+
 	"github.com/cmaster11/k8s-event-watcher"
 	"k8s.io/api/core/v1"
 	_ "k8s.io/client-go/plugin/pkg/client/auth"
-	"log"
-	"os"
 )
 
 func main() {
@@ -26,8 +27,8 @@ func main() {
 		log.Fatal(err)
 	}
 
-	if err := watcher.Start(func(event *v1.Event, eventFilter *k8seventwatcher.EventFilter) {
-		log.Printf("got event (%s): %+v\n", eventFilter.String(), event)
+	if err := watcher.Start(func(event *v1.Event, eventFilter *k8seventwatcher.EventFilter, matchedFields map[string]interface{}) {
+		log.Printf("got event (%s):\nmatchedFields: %+v\nevent: %+v\n", eventFilter.String(), matchedFields, event)
 	}); err != nil {
 		log.Fatal(err)
 	}

filter.go

@@ -20,20 +20,23 @@ func (f *EventFilter) Validate() error {
 	return errors.New("no rules provided")
 }
 
-func (f *EventFilter) Matches(event map[string]interface{}) (bool, error) {
+func (f *EventFilter) Matches(event map[string]interface{}) (map[string]interface{}, error) {
+	matchedFields := make(map[string]interface{})
 	for path, regex := range f.Rules {
 		value, err := lookup.LookupString(event, path)
 		if err != nil {
-			return false, errorf("lookup error: %s", err)
+			return nil, errorf("lookup error: %s", err)
 		}
 
 		valueStr := fmt.Sprintf("%v", value.Interface())
 		if !regex.MatchString(valueStr) {
-			return false, nil
+			return nil, nil
 		}
+
+		matchedFields[path] = valueStr
 	}
 
-	return true, nil
+	return matchedFields, nil
 }
 
 func (f *EventFilter) String() string {

filter_test.go

@@ -41,13 +41,16 @@ rules:
 		t.Fatalf("failed to cast event to map: %s", err)
 	}
 
-	match, err := filter.Matches(obj)
+	matchedFields, err := filter.Matches(obj)
 	if err != nil {
 		t.Fatalf("match error: %s", err)
 	}
-	if !match {
+	if matchedFields == nil {
 		t.Fatalf("no match")
 	}
+	if matchedFields["involvedObject.name"] != evt.InvolvedObject.Name {
+		t.Fatalf("bad matched field")
+	}
 
 	output := filter.ToYAML()
 

main.go

@@ -1,9 +1,13 @@
 package k8seventwatcher
 
 import (
-	"gopkg.in/yaml.v2"
 	"io"
 	"io/ioutil"
+	"log"
+	"sync"
+	"time"
+
+	"gopkg.in/yaml.v2"
 	"k8s.io/api/core/v1"
 	v12 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/client-go/informers"
@@ -12,9 +16,6 @@ import (
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/cache"
 	"k8s.io/client-go/tools/clientcmd"
-	"log"
-	"sync"
-	"time"
 )
 
 type K8sEventWatcher struct {
@@ -26,15 +27,15 @@ type K8sEventWatcher struct {
 
 	chStop   chan struct{}
 	lock     sync.Mutex
-	callback func(event *v1.Event, eventFilter *EventFilter)
+	callback func(event *v1.Event, eventFilter *EventFilter, matchedFields map[string]interface{})
 
 	Debug bool
 }
 
 func NewK8sEventWatcher(
-	// Config path of event watcher
+// Config path of event watcher
 	configPath string,
-	// Config path for k8s cluster, can be empty
+// Config path for k8s cluster, can be empty
 	kubeConfigPath *string,
 	logWriter io.Writer,
 ) (*K8sEventWatcher, error) {
@@ -114,21 +115,21 @@ func (w *K8sEventWatcher) onAddEvent(obj interface{}) {
 		return
 	}
 
-	filter, err := w.config.MatchingEventFilter(outMap)
+	filter, matchedFields, err := w.config.MatchingEventFilter(outMap)
 	if err != nil {
 		w.logEntryError("failed to find matching event filter: %+v", err)
 		return
 	}
 	if filter != nil {
 		w.logEntryDebug("matched event: %+v", evt)
-		w.callback(evt, filter)
+		w.callback(evt, filter, matchedFields)
 		return
 	}
 
 	w.logEntryDebug("discarded event: %+v", evt)
 }
 
-func (w *K8sEventWatcher) Start(callback func(event *v1.Event, eventFilter *EventFilter)) error {
+func (w *K8sEventWatcher) Start(callback func(event *v1.Event, eventFilter *EventFilter, matchedFields map[string]interface{})) error {
 	if callback == nil {
 		return errorf("callback cannot be null")
 	}