Call an optional webhook before killing a pod

README.md

@@ -90,6 +90,8 @@ spec:
         - --timezone=Europe/Berlin
         # exclude all pods that haven't been running for at least one hour
         - --minimum-age=1h
+        # check with a webhook before killing a pod
+        - --webhook=https://httpbin.org/post
         # terminate pods for real: this disables dry-run mode which is on by default
         # - --no-dry-run
 ```
@@ -234,6 +236,7 @@ Use `UTC`, `Local` or pick a timezone name from the [(IANA) tz database](https:/
 | `--dry-run`               | don't kill pods, only log what would have been done                  | true                       |
 | `--log-format`            | specify the format of the log messages. Options are text and json    | text                       |
 | `--log-caller`            | include the calling function name and location in the log messages   | false                      |
+| `--webhook`               | filter pods by a POST webhook, if non HTTP 200 returned, exclude pod | no webhook calls           |
 
 ## Related work
 

chaoskube/chaoskube.go

@@ -1,10 +1,14 @@
 package chaoskube
 
 import (
+	"bytes"
 	"context"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"math/rand"
+	"net/http"
+	"net/url"
 	"regexp"
 	"time"
 
@@ -63,6 +67,8 @@ type Chaoskube struct {
 	EventRecorder record.EventRecorder
 	// a function to retrieve the current time
 	Now func() time.Time
+	// Webhook
+	Webhook url.URL
 }
 
 var (
@@ -86,7 +92,7 @@ var (
 // * a logger implementing logrus.FieldLogger to send log output to
 // * what specific terminator to use to imbue chaos on victim pods
 // * whether to enable/disable dry-run mode
-func New(client kubernetes.Interface, labels, annotations, namespaces, namespaceLabels labels.Selector, includedPodNames, excludedPodNames *regexp.Regexp, excludedWeekdays []time.Weekday, excludedTimesOfDay []util.TimePeriod, excludedDaysOfYear []time.Time, timezone *time.Location, minimumAge time.Duration, logger log.FieldLogger, dryRun bool, terminator terminator.Terminator) *Chaoskube {
+func New(client kubernetes.Interface, labels, annotations, namespaces, namespaceLabels labels.Selector, includedPodNames, excludedPodNames *regexp.Regexp, excludedWeekdays []time.Weekday, excludedTimesOfDay []util.TimePeriod, excludedDaysOfYear []time.Time, timezone *time.Location, minimumAge time.Duration, logger log.FieldLogger, dryRun bool, terminator terminator.Terminator, Webhook url.URL) *Chaoskube {
 	broadcaster := record.NewBroadcaster()
 	broadcaster.StartRecordingToSink(&typedcorev1.EventSinkImpl{Interface: client.CoreV1().Events(v1.NamespaceAll)})
 	recorder := broadcaster.NewRecorder(scheme.Scheme, v1.EventSource{Component: "chaoskube"})
@@ -109,6 +115,7 @@ func New(client kubernetes.Interface, labels, annotations, namespaces, namespace
 		Terminator:         terminator,
 		EventRecorder:      recorder,
 		Now:                time.Now,
+		Webhook:            Webhook,
 	}
 }
 
@@ -212,6 +219,7 @@ func (c *Chaoskube) Candidates() ([]v1.Pod, error) {
 	pods = filterByPhase(pods, v1.PodRunning)
 	pods = filterByMinimumAge(pods, c.MinimumAge, c.Now())
 	pods = filterByPodName(pods, c.IncludedPodNames, c.ExcludedPodNames)
+	pods = filterByWebhook(pods, c.Webhook)
 
 	return pods, nil
 }
@@ -409,3 +417,29 @@ func filterByPodName(pods []v1.Pod, includedPodNames, excludedPodNames *regexp.R
 
 	return filteredList
 }
+
+// filterByWebhook filters pods by a POST webhook. Only pods where the webhooks returns an
+// HTTP 200 are returned
+func filterByWebhook(pods []v1.Pod, url url.URL) []v1.Pod {
+	// return early if url is not given
+	if url.String() == "" {
+		return pods
+	}
+
+	filteredList := []v1.Pod{}
+
+	for _, pod := range pods {
+		postData := new(bytes.Buffer)
+		json.NewEncoder(postData).Encode(pod)
+		resp, err := http.Post(url.String(), "application/json", postData)
+		if err != nil {
+			continue
+		}
+
+		if resp.StatusCode == http.StatusOK {
+			filteredList = append(filteredList, pod)
+		}
+	}
+
+	return filteredList
+}

go.sum

@@ -11,6 +11,7 @@ github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRF
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
 github.com/beorn7/perks v1.0.0 h1:HWo1m869IqiPhD389kmkxeTalrjNbbJTC8LXupb+sl0=
 github.com/beorn7/perks v1.0.0/go.mod h1:KWe93zE9D1o94FZ5RNwFwVgaQK1VOXiVxmqh+CedLV8=
+github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
@@ -37,12 +38,14 @@ github.com/golang/groupcache v0.0.0-20160516000752-02826c3e7903/go.mod h1:cIg4er
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.3.1 h1:YF8+flBXS5eO826T4nzqPrxfhQThhXl0YzfuUPu4SBg=
 github.com/golang/protobuf v1.3.1/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/golang/protobuf v1.3.2 h1:6nsPYzhq5kReh6QImI3k5qWzO4PEbvbIW2cwSfR/6xs=
 github.com/golang/protobuf v1.3.2/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/google/btree v0.0.0-20160524151835-7d79101e329e/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ5JPQ=
 github.com/google/go-cmp v0.3.0 h1:crn/baboCvb5fXaQ0IJ1SGTsTVrWpDsCWC8EGETZijY=
 github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/google/gofuzz v0.0.0-20170612174753-24818f796faf h1:+RRA9JqSOZFfKrOeqr2z77+8R2RKyh8PG66dcu1V0ck=
 github.com/google/gofuzz v0.0.0-20170612174753-24818f796faf/go.mod h1:HP5RmnzzSNb993RKQDq4+1A4ia9nllfqcQFTQJedwGI=
+github.com/google/gofuzz v1.0.0 h1:A8PeW59pxE9IoFRqBp37U+mSNaQoZ46F1f0f863XSXw=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/google/uuid v1.0.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/googleapis/gnostic v0.0.0-20170729233727-0c5108395e2d h1:7XGaL1e6bYS1yIonGp9761ExpPPV1ui0SAC59Yube9k=
@@ -60,6 +63,7 @@ github.com/imdario/mergo v0.3.7/go.mod h1:2EnlNZ0deacrJVfApfmtdGgDfMuh/nq6Ok1EcJ
 github.com/json-iterator/go v0.0.0-20180701071628-ab8a2e0c74be/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
 github.com/json-iterator/go v1.1.6 h1:MrUvLMLTMxbqFJ9kzlvat/rYZqZnW3u4wkLzWTaFwKs=
 github.com/json-iterator/go v1.1.6/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
+github.com/json-iterator/go v1.1.7 h1:KfgG9LzI+pYjr4xvmz/5H4FXjokeP+rlHLhv3iH62Fo=
 github.com/json-iterator/go v1.1.7/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
 github.com/julienschmidt/httprouter v1.2.0/go.mod h1:SYymIcj16QtmaHHD7aYtjjsJG7VTCxuUUipMqKk8s4w=
 github.com/konsorten/go-windows-terminal-sequences v1.0.1 h1:mweAR1A6xJ3oS2pRaGiHgQ4OO8tzTaLawm8vnODuwDk=
@@ -93,10 +97,12 @@ github.com/prometheus/client_model v0.0.0-20190129233127-fd36f4220a90 h1:S/YWwWx
 github.com/prometheus/client_model v0.0.0-20190129233127-fd36f4220a90/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
 github.com/prometheus/common v0.4.1 h1:K0MGApIoQvMw27RTdJkPbr3JZ7DNbtxQNyi5STVM6Kw=
 github.com/prometheus/common v0.4.1/go.mod h1:TNfzLD0ON7rHzMJeJkieUDPYmFC7Snx/y86RQel1bk4=
+github.com/prometheus/common v0.6.0 h1:kRhiuYSXR3+uv2IbVbZhUxK5zVD/2pp3Gd2PpvPkpEo=
 github.com/prometheus/common v0.6.0/go.mod h1:eBmuwkDJBwy6iBfxCBob6t6dR6ENT/y+J+Zk0j9GMYc=
 github.com/prometheus/procfs v0.0.0-20181005140218-185b4288413d/go.mod h1:c3At6R/oaqEKCNdg8wHV1ftS6bRYblBhIjjI8uT2IGk=
 github.com/prometheus/procfs v0.0.2 h1:6LJUbpNm42llc4HRCuvApCSWB/WfhuNo9K98Q9sNGfs=
 github.com/prometheus/procfs v0.0.2/go.mod h1:TjEm7ze935MbeOT/UhFTIMYKhuLP4wbCsTZCD3I8kEA=
+github.com/prometheus/procfs v0.0.3 h1:CTwfnzjQ+8dS6MhHHu4YswVAD99sL2wjPqP+VkURmKE=
 github.com/prometheus/procfs v0.0.3/go.mod h1:4A/X28fw3Fc593LaREMrKMqOKvUAntwMDaekg4FpcdQ=
 github.com/sirupsen/logrus v1.2.0/go.mod h1:LxeOpSwHxABJmUn/MG1IvRgCAasNZTLOkJPxbbu5VWo=
 github.com/sirupsen/logrus v1.4.2 h1:SPIRibHv4MatM3XXNO2BJeFLZwZ2LvZgfQ5+UNI2im4=
@@ -116,13 +122,15 @@ golang.org/x/crypto v0.0.0-20180904163835-0709b304e793/go.mod h1:6SG95UA2DQfeDnf
 golang.org/x/crypto v0.0.0-20181025213731-e84da0312774/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
 golang.org/x/crypto v0.0.0-20190211182817-74369b46fc67 h1:ng3VDlRp5/DHpSWl02R4rM9I+8M2rhmsuLwAMmkLQWE=
 golang.org/x/crypto v0.0.0-20190211182817-74369b46fc67/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2 h1:VklqNMn3ovrHsnt90PveolxSbWFaJdECFbxSq0Mqo2M=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/net v0.0.0-20180724234803-3673e40ba225/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20180906233101-161cd47e91fd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20181114220301-adae6a3d119a/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20190108225652-1e06a53dbb7e/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20190206173232-65e2d4e15006 h1:bfLnR+k0tq5Lqt6dflRLcZiz6UaXCMt3vhYJ1l4FQ80=
 golang.org/x/net v0.0.0-20190206173232-65e2d4e15006/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20190613194153-d28f0bde5980 h1:dfGZHvZk057jK2MCeWus/TowKpJ8y4AmooUzdBSR9GU=
 golang.org/x/net v0.0.0-20190613194153-d28f0bde5980/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/oauth2 v0.0.0-20190402181905-9f3314589c9a/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/oauth2 v0.0.0-20190604053449-0f29369cfe45 h1:SVwTIAaPC2U/AvvLNZ2a7OVsmBpC8L5BlwK1whH3hm0=
@@ -138,6 +146,7 @@ golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5h
 golang.org/x/sys v0.0.0-20190312061237-fead79001313/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190422165155-953cdadca894 h1:Cz4ceDQGXuKRnVBDTS23GTn/pU5OE2C0WrNTOYK1Uuc=
 golang.org/x/sys v0.0.0-20190422165155-953cdadca894/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20190801041406-cbf593c0f2f3 h1:4y9KwBHBgBNwDbtu44R5o1fdOCQUEXhbk/P4A9WmJq0=
 golang.org/x/sys v0.0.0-20190801041406-cbf593c0f2f3/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.1-0.20181227161524-e6919f6577db h1:6/JqlYfC1CCaLnGceQTI+sDGhC9UBSPAsBqI0Gun6kU=

main.go

@@ -7,6 +7,7 @@ import (
 	"math/rand"
 	"net/http"
 	_ "net/http/pprof"
+	"net/url"
 	"os"
 	"os/signal"
 	"path"
@@ -52,6 +53,7 @@ var (
 	dryRun             bool
 	debug              bool
 	metricsAddress     string
+	webhook            string
 	gracePeriod        time.Duration
 	logFormat          string
 	logCaller          bool
@@ -67,6 +69,7 @@ func init() {
 	kingpin.Flag("namespace-labels", "A set of labels to restrict the list of affected namespaces. Defaults to everything.").StringVar(&nsLabelString)
 	kingpin.Flag("included-pod-names", "Regular expression that defines which pods to include. All included by default.").RegexpVar(&includedPodNames)
 	kingpin.Flag("excluded-pod-names", "Regular expression that defines which pods to exclude. None excluded by default.").RegexpVar(&excludedPodNames)
+	kingpin.Flag("webhook", "An HTTP webhook to execute before killing a pod").StringVar(&webhook)
 	kingpin.Flag("excluded-weekdays", "A list of weekdays when termination is suspended, e.g. Sat,Sun").StringVar(&excludedWeekdays)
 	kingpin.Flag("excluded-times-of-day", "A list of time periods of a day when termination is suspended, e.g. 22:00-08:00").StringVar(&excludedTimesOfDay)
 	kingpin.Flag("excluded-days-of-year", "A list of days of a year when termination is suspended, e.g. Apr1,Dec24").StringVar(&excludedDaysOfYear)
@@ -120,6 +123,7 @@ func main() {
 		"metricsAddress":     metricsAddress,
 		"gracePeriod":        gracePeriod,
 		"logFormat":          logFormat,
+		"webhook":            webhook,
 	}).Debug("reading config")
 
 	log.WithFields(log.Fields{
@@ -181,6 +185,14 @@ func main() {
 	}
 	timezoneName, offset := time.Now().In(parsedTimezone).Zone()
 
+	parsedWebhook, err := url.Parse(webhook)
+	if err != nil {
+		log.WithFields(log.Fields{
+			"webhook": webhook,
+			"err":     err,
+		}).Fatal("failed to parse webhook")
+	}
+
 	log.WithFields(log.Fields{
 		"name":     timezoneName,
 		"location": parsedTimezone,
@@ -203,6 +215,7 @@ func main() {
 		log.StandardLogger(),
 		dryRun,
 		terminator.NewDeletePodTerminator(client, log.StandardLogger(), gracePeriod),
+		*parsedWebhook,
 	)
 
 	if metricsAddress != "" {