Kubernetes logging (#1054)

* wip

* Implementation of Kubernetes Logger

* Missing file

* Skip test in Travis

debug/log/kubernetes/kubernetes.go

@@ -2,15 +2,62 @@
 package kubernetes
 
 import (
-	"errors"
+	"bufio"
+	"encoding/json"
+	"fmt"
+	"os"
+	"sort"
+	"strconv"
+	"time"
 
 	"github.com/micro/go-micro/debug/log"
+	"github.com/micro/go-micro/util/kubernetes/client"
 )
 
-type klog struct{}
+type klog struct {
+	client client.Kubernetes
 
-func (k *klog) Read(...log.ReadOption) ([]log.Record, error) {
-	return nil, errors.New("not implemented")
+	log.Options
+}
+
+func (k *klog) Read(options ...log.ReadOption) ([]log.Record, error) {
+	opts := &log.ReadOptions{}
+	for _, o := range options {
+		o(opts)
+	}
+
+	logsToGet, err := k.getMatchingPods()
+	if err != nil {
+		return nil, err
+	}
+	records := []log.Record{}
+
+	for _, l := range logsToGet {
+		logParams := make(map[string]string)
+		if !opts.Since.Equal(time.Time{}) {
+			logParams["sinceSeconds"] = strconv.Itoa(int(time.Since(opts.Since).Seconds()))
+		}
+		if opts.Count != 0 {
+			logParams["tailLines"] = strconv.Itoa(opts.Count)
+		}
+		if opts.Stream == true {
+			logParams["follow"] = "true"
+		}
+		logs, err := k.client.Logs(l, client.AdditionalParams(logParams))
+		if err != nil {
+			return nil, err
+		}
+		defer logs.Close()
+		s := bufio.NewScanner(logs)
+		for s.Scan() {
+			record := k.parse(s.Text())
+			record.Metadata["pod"] = l
+			records = append(records, record)
+		}
+	}
+
+	sort.Sort(byTimestamp(records))
+	return records, nil
 }
 
 func (k *klog) Write(l log.Record) error {
@@ -18,13 +65,102 @@ func (k *klog) Write(l log.Record) error {
 }
 
 func (k *klog) Stream() (log.Stream, error) {
-	return &klogStreamer{
+	return k.stream()
+}
+
+func (k *klog) stream() (log.Stream, error) {
+	pods, err := k.getMatchingPods()
+	if err != nil {
+		return nil, err
+	}
+	logStreamer := &klogStreamer{
 		streamChan: make(chan log.Record),
 		stop:       make(chan bool),
-	}, nil
+	}
+	errorChan := make(chan error)
+	go func(stopChan <-chan bool) {
+		for {
+			select {
+			case <-stopChan:
+				return
+			case err := <-errorChan:
+				fmt.Fprintf(os.Stderr, err.Error())
+			}
+		}
+	}(logStreamer.stop)
+	for _, pod := range pods {
+		go k.individualPodLogStreamer(pod, logStreamer.streamChan, errorChan, logStreamer.stop)
+	}
+	return logStreamer, nil
+}
+
+func (k *klog) individualPodLogStreamer(podName string, recordChan chan<- log.Record, errorChan chan<- error, stopChan <-chan bool) {
+	p := make(map[string]string)
+	p["follow"] = "true"
+	body, err := k.client.Logs(podName, client.AdditionalParams(p))
+	if err != nil {
+		errorChan <- err
+		return
+	}
+	s := bufio.NewScanner(body)
+	defer body.Close()
+	for {
+		select {
+		case <-stopChan:
+			return
+		default:
+			if s.Scan() {
+				record := k.parse(s.Text())
+				recordChan <- record
+			} else {
+				time.Sleep(time.Second)
+			}
+		}
+	}
 }
 
 // New returns a configured Kubernetes logger
-func New() log.Log {
-	return &klog{}
+func New(opts ...log.Option) log.Log {
+	klog := &klog{}
+	for _, o := range opts {
+		o(&klog.Options)
+	}
+
+	if len(os.Getenv("KUBERNETES_SERVICE_HOST")) > 0 {
+		klog.client = client.NewClientInCluster()
+	} else {
+		klog.client = client.NewLocalDevClient()
+	}
+	return klog
+}
+
+func (k *klog) getMatchingPods() ([]string, error) {
+	r := &client.Resource{
+		Kind:  "pod",
+		Value: new(client.PodList),
+	}
+	l := make(map[string]string)
+	l["micro"] = "runtime"
+	if err := k.client.Get(r, l); err != nil {
+		return nil, err
+	}
+
+	var matches []string
+	for _, p := range r.Value.(*client.PodList).Items {
+		if p.Metadata.Labels["name"] == k.Options.Name {
+			matches = append(matches, p.Metadata.Name)
+		}
+	}
+	return matches, nil
+}
+
+func (k *klog) parse(line string) log.Record {
+	record := log.Record{}
+	if err := json.Unmarshal([]byte(line), &record); err != nil {
+		record.Timestamp = time.Now().UTC()
+		record.Message = line
+		record.Metadata = make(map[string]string)
+	}
+	record.Metadata["service"] = k.Options.Name
+	return record
 }