Switch to golang due to bug in fluent-plugin-kubernetes-objects (#3)

* initial commit, still learning

* testing another approach

* fixed

* print in json

* Remove flag package

* update README and docker image tag

* switching docker to use multistage

Author: max-rocket-internet

Dockerfile

@@ -1,43 +1,11 @@
-FROM fluent/fluentd:v1.3.3-debian-1.0
-
-USER root
-WORKDIR /home/fluent
-ENV PATH /fluentd/vendor/bundle/ruby/2.3.0/bin:$PATH
-ENV GEM_PATH /fluentd/vendor/bundle/ruby/2.3.0
-ENV GEM_HOME /fluentd/vendor/bundle/ruby/2.3.0
-# skip runtime bundler installation
-ENV FLUENTD_DISABLE_BUNDLER_INJECTION 1
-
-COPY ./conf/Gemfile /fluentd/
-
-RUN buildDeps="sudo make gcc g++ libc-dev ruby-dev libffi-dev" \
-     && apt-get update \
-     && apt-get upgrade -y \
-     && apt-get install \
-     -y --no-install-recommends \
-     $buildDeps net-tools libjemalloc1 \
-    && gem install bundler --version 1.16.2 \
-    && bundle config silence_root_warning true \
-    && bundle install --gemfile=/fluentd/Gemfile --path=/fluentd/vendor/bundle \
-    && SUDO_FORCE_REMOVE=yes \
-    apt-get purge -y --auto-remove \
-                  -o APT::AutoRemove::RecommendsImportant=false \
-                  $buildDeps \
- && rm -rf /var/lib/apt/lists/* \
-    && gem sources --clear-all \
-    && rm -rf /tmp/* /var/tmp/* /usr/lib/ruby/gems/*/cache/*.gem
-
-# Copy configuration files
-COPY ./conf/fluent.conf /fluentd/etc/
-RUN touch /fluentd/etc/disable.conf
-COPY ./conf/entrypoint.sh /fluentd/entrypoint.sh
-
-# Environment variables
-ENV FLUENTD_OPT=""
-ENV FLUENTD_CONF="fluent.conf"
-
-# See https://packages.debian.org/stretch/amd64/libjemalloc1/filelist
-ENV LD_PRELOAD="/usr/lib/x86_64-linux-gnu/libjemalloc.so.1"
-
-# Overwrite ENTRYPOINT to run fluentd as root for /var/log / /var/lib
-ENTRYPOINT ["tini", "--", "/fluentd/entrypoint.sh"]
+FROM golang:1.12.1
+WORKDIR /go/src/github.com/deliveryhero/k8s-event-logger
+COPY main.go .
+RUN go get -d -v ./...
+RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o main .
+
+FROM alpine:3.9.3
+RUN apk --no-cache add ca-certificates
+WORKDIR /root/
+COPY --from=0 /go/src/github.com/deliveryhero/k8s-event-logger/main k8s-event-logger
+CMD ["/root/k8s-event-logger"]

README.md

@@ -11,11 +11,6 @@ The problem is that these events are simply API objects in Kubernetes and are on
 
 This simple container and [Helm](https://helm.sh/) chart will run in your cluster, watch for events and print them to stdout in JSON. The assumption is that you already have a daemonset for collecting all pod logs and sending them to a central system, e.g. ELK, Splunk, Graylog etc.
 
-It's based on work in these 2 repositories:
-
-- https://github.com/splunk/fluent-plugin-kubernetes-objects
-- https://github.com/fluent/fluentd-kubernetes-daemonset
-
 ### Installation
 
 Use the [Helm](https://helm.sh/) chart:

chart/values.yaml

@@ -1,6 +1,6 @@
 image:
   repository: deliveryherotech/k8s-event-logger
-  tag: "1.1"
+  tag: "1.2"
   pullPolicy: IfNotPresent
 
 resources:

conf/Gemfile

@@ -0,0 +1,78 @@
+package main
+
+import (
+  "fmt"
+  "log"
+  "os"
+  "time"
+  "os/user"
+  "encoding/json"
+  "k8s.io/api/core/v1"
+  "k8s.io/client-go/kubernetes"
+  "k8s.io/client-go/tools/clientcmd"
+  "k8s.io/client-go/rest"
+  "k8s.io/client-go/tools/cache"
+  "k8s.io/apimachinery/pkg/fields"
+)
+
+func main() {
+  usr, err := user.Current()
+  if err != nil {
+      log.Fatal( err )
+  }
+
+  var config *rest.Config
+
+  if k8s_port := os.Getenv("KUBERNETES_PORT"); k8s_port == "" {
+    fmt.Println("Using local kubeconfig")
+    var kubeconfig string
+    home := usr.HomeDir
+  	if home != "" {
+  		kubeconfig = fmt.Sprintf("%s/.kube/config", home)
+  	} else {
+  		panic("home directory unknown")
+  	}
+
+  	config, err = clientcmd.BuildConfigFromFlags("", kubeconfig)
+  	if err != nil {
+  		panic(err.Error())
+  	}
+  } else {
+    fmt.Println("Using in cluster authentication")
+    config, err = rest.InClusterConfig()
+  	if err != nil {
+  		panic(err.Error())
+  	}
+  }
+
+  clientset, err := kubernetes.NewForConfig(config)
+  if err != nil {
+    panic(err.Error())
+  }
+
+  watchlist := cache.NewListWatchFromClient(
+      clientset.CoreV1().RESTClient(),
+      "events",
+      v1.NamespaceAll,
+      fields.Everything(),
+  )
+  _, controller := cache.NewInformer(
+      watchlist,
+      &v1.Event{},
+      0, //Duration is int64
+      cache.ResourceEventHandlerFuncs{
+          AddFunc: func(obj interface{}) {
+              j, _ := json.Marshal(obj)
+              fmt.Printf("%s\n", string(j))
+          },
+       },
+   )
+
+  stop := make(chan struct{})
+  defer close(stop)
+  go controller.Run(stop)
+  for {
+      time.Sleep(time.Second)
+  }
+
+}