first working version

Author: cmaster11

.gitignore

@@ -1 +1,2 @@
-.idea
+.idea
+config.yaml

config.yaml

@@ -0,0 +1,4 @@
+sinceNow: true
+filters:
+  - objectKind: Job
+    eventReason: BackoffLimitExceeded

example.yaml.ref

@@ -0,0 +1,29 @@
+apiVersion: v1
+items:
+- apiVersion: v1
+  count: 1
+  eventTime: null
+  firstTimestamp: "2019-10-14T07:11:45Z"
+  involvedObject:
+    apiVersion: batch/v1
+    kind: Job
+    name: test
+    namespace: default
+    resourceVersion: "101294040"
+    uid: dfe0b858-ee51-11e9-ae04-0a92e6d821d8
+  kind: Event
+  lastTimestamp: "2019-10-14T07:11:45Z"
+  message: Job has reached the specified backoff limit
+  metadata:
+    creationTimestamp: "2019-10-14T07:11:45Z"
+    name: test.15cd71ec765990ca
+    namespace: default
+    resourceVersion: "101294059"
+    selfLink: /api/v1/namespaces/default/events/test.15cd71ec765990ca
+    uid: e17d1c66-ee51-11e9-9a81-12fd51bfaa24
+  reason: BackoffLimitExceeded
+  reportingComponent: ""
+  reportingInstance: ""
+  source:
+    component: job-controller
+  type: Warning

example/main.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"bufio"
+	"flag"
+	"fmt"
+	v1 "k8s.io/api/core/v1"
+	_ "k8s.io/client-go/plugin/pkg/client/auth"
+	"k8seventwatcher"
+	"log"
+	"os"
+)
+
+func main() {
+	kubeConfigPath := flag.String("kubeconfig", "", "path of k8s k8sConfig file to use")
+	configPath := flag.String("config", "config.yaml", "path of k8sConfig file to use")
+
+	flag.Parse()
+
+	watcher, err := k8seventwatcher.NewK8sEventWatcher(
+		*configPath,
+		kubeConfigPath,
+		os.Stdout,
+	)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	if err := watcher.Start(func(event *v1.Event) {
+		log.Printf("got event: %+v\n", event)
+	}); err != nil {
+		log.Fatal(err)
+	}
+
+	fmt.Println("Press 'Enter' to exit...")
+	bufio.NewReader(os.Stdin).ReadBytes('\n')
+
+	watcher.Stop()
+}

go.mod

@@ -1,8 +1,10 @@
-module k8s-event-watcher
+module k8seventwatcher
 
 go 1.13
 
 require (
+	gopkg.in/yaml.v2 v2.2.4
 	k8s.io/api v0.0.0-20190620084959-7cf5895f2711
+	k8s.io/apimachinery v0.0.0-20190612205821-1799e75a0719
 	k8s.io/client-go v0.0.0-20190620085101-78d2af792bab
 )

go.sum

@@ -74,6 +74,8 @@ gopkg.in/inf.v0 v0.9.0/go.mod h1:cWUDdTG/fYaXco+Dcufb5Vnc6Gp2YChqWtbxRZE0mXw=
 gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7/go.mod h1:dt/ZhP58zS4L8KSrWDmTeBkI65Dw0HsyUHuEVlX15mw=
 gopkg.in/yaml.v2 v2.2.1 h1:mUhvW9EsL+naU5Q3cakzfE91YhliOondGd6ZrsDBHQE=
 gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.4 h1:/eiJrUcujPVeJ3xlSWaiNi3uSVmDGBK1pDHUHAnao1I=
+gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 k8s.io/api v0.0.0-20190620084959-7cf5895f2711 h1:BblVYz/wE5WtBsD/Gvu54KyBUTJMflolzc5I2DTvh50=
 k8s.io/api v0.0.0-20190620084959-7cf5895f2711/go.mod h1:TBhBqb1AWbBQbW3XRusr7n7E4v2+5ZY8r8sAMnyFC5A=
 k8s.io/apimachinery v0.0.0-20190612205821-1799e75a0719 h1:uV4S5IB5g4Nvi+TBVNf3e9L4wrirlwYJ6w88jUQxTUw=

internal/config.go

@@ -0,0 +1,48 @@
+package internal
+
+import (
+	"errors"
+	"gopkg.in/yaml.v2"
+	v1 "k8s.io/api/core/v1"
+	"log"
+)
+
+type Config struct {
+	Filters []*EventFilter `yaml:"filters"`
+
+	// If true, accepts only events generated since the app has been launched
+	SinceNow bool `yaml:"sinceNow"`
+}
+
+func (c *Config) Validate() error {
+	if len(c.Filters) == 0 {
+		return errors.New("zero filters provided")
+	}
+
+	for _, filter := range c.Filters {
+		if err := filter.Validate(); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (c *Config) MatchesEvent(event *v1.Event) bool {
+	for _, filter := range c.Filters {
+		if filter.Matches(event) {
+			return true
+		}
+	}
+
+	return false
+}
+
+func (c *Config) Dump() string {
+	data, err := yaml.Marshal(c)
+	if err != nil {
+		log.Fatalf("failed to dump Config: %+v", c)
+	}
+
+	return string(data)
+}

internal/filter.go

@@ -0,0 +1,64 @@
+package internal
+
+import (
+	"errors"
+	v1 "k8s.io/api/core/v1"
+)
+
+type EventFilter struct {
+	ObjectNamespace *Regexp `yaml:"objectNamespace,omitempty"`
+	ObjectKind      *Regexp `yaml:"objectKind,omitempty"`
+	ObjectName      *Regexp `yaml:"objectName,omitempty"`
+	EventType       *Regexp `yaml:"eventType,omitempty"`
+	EventReason     *Regexp `yaml:"eventReason,omitempty"`
+}
+
+func (f *EventFilter) Validate() error {
+	// At least one filter must exist
+	if f.ObjectNamespace != nil {
+		return nil
+	}
+	if f.ObjectKind != nil {
+		return nil
+	}
+	if f.ObjectName != nil {
+		return nil
+	}
+	if f.EventType != nil {
+		return nil
+	}
+	if f.EventReason != nil {
+		return nil
+	}
+	return errors.New("no filter attributes provided")
+}
+
+func (f *EventFilter) Matches(event *v1.Event) bool {
+	if f.ObjectNamespace != nil {
+		if !f.ObjectNamespace.MatchString(event.InvolvedObject.Namespace) {
+			return false
+		}
+	}
+	if f.ObjectKind != nil {
+		if !f.ObjectKind.MatchString(event.InvolvedObject.Kind) {
+			return false
+		}
+	}
+	if f.ObjectName != nil {
+		if !f.ObjectName.MatchString(event.InvolvedObject.Name) {
+			return false
+		}
+	}
+	if f.EventType != nil {
+		if !f.EventType.MatchString(event.Type) {
+			return false
+		}
+	}
+	if f.EventReason != nil {
+		if !f.EventReason.MatchString(event.Reason) {
+			return false
+		}
+	}
+
+	return true
+}

internal/regex.go

@@ -0,0 +1,26 @@
+package internal
+
+import "regexp"
+
+type Regexp struct {
+	*regexp.Regexp
+}
+
+func (r *Regexp) UnmarshalYAML(unmarshal func(interface{}) error) error {
+	regexString := ""
+	err := unmarshal(&regexString)
+	if err != nil {
+		return err
+	}
+
+	(*r).Regexp, err = regexp.Compile(regexString)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (r *Regexp) MarshalYAML() (interface{}, error) {
+	return r.Regexp.String(), nil
+}

log.go

@@ -0,0 +1,28 @@
+package k8seventwatcher
+
+import "fmt"
+
+func (w *K8sEventWatcher) logEntryDebug(format string, args ...interface{}) {
+	if ! w.Debug {
+		return
+	}
+	if w.logger != nil {
+		w.logger.Printf("[K8EW] (DEBUG): "+format+"\n", args...)
+	}
+}
+
+func (w *K8sEventWatcher) logEntryInfo(format string, args ...interface{}) {
+	if w.logger != nil {
+		w.logger.Printf("[K8EW] (INFO): "+format+"\n", args...)
+	}
+}
+
+func (w *K8sEventWatcher) logEntryError(format string, args ...interface{}) {
+	if w.logger != nil {
+		w.logger.Printf("[K8EW] (ERROR): "+format+"\n", args...)
+	}
+}
+
+func errorf(format string, args ...interface{}) error {
+	return fmt.Errorf("[K8EW]: "+format+"\n", args)
+}