Initial features pt 2 (#3)

* Less logging when not in DEBUG

* Check helm is fine

* Display kube context switch

* Cosmetics

* Displays list of chartss

* Linter stuff

* Fix option name

pkg/dashboard/main.go

@@ -1,16 +1,125 @@
 package dashboard
 
 import (
-	"helm.sh/helm/v3/pkg/release"
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	log "github.com/sirupsen/logrus"
+	"os/exec"
+	"regexp"
+	"strings"
 )
 
 type DataLayer struct {
 }
 
-func (l *DataLayer) CheckConnectivity() {
-	// TODO: check that we can work with context and subcommands
+func (l *DataLayer) runCommand(cmd ...string) (string, error) {
+	// TODO: --kube-context=context-name to juggle clusters
+	log.Debugf("Starting command: %s", cmd)
+	prog := exec.Command(cmd[0], cmd[1:]...)
+
+	var stdout bytes.Buffer
+	prog.Stdout = &stdout
+
+	var stderr bytes.Buffer
+	prog.Stderr = &stderr
+
+	//prog.Stdout, prog.Stderr = os.Stdout, os.Stderr
+	if err := prog.Run(); err != nil {
+		if eerr, ok := err.(*exec.ExitError); ok {
+			return "", fmt.Errorf("failed to run command %s: %s", cmd, eerr)
+		}
+		return "", err
+	}
+
+	sout := stdout.Bytes()
+	serr := stderr.Bytes()
+	log.Debugf("Command STDOUT:\n%s", sout)
+	log.Debugf("Command STDERR:\n%s", serr)
+	return string(sout), nil
 }
 
-func (l *DataLayer) ListInstalled() []*release.Release {
-	return nil // TODO
+func (l *DataLayer) CheckConnectivity() error {
+	contexts, err := l.ListContexts()
+	if err != nil {
+		return err
+	}
+
+	if len(contexts) < 1 {
+		return errors.New("did not find any kubectl contexts configured")
+	}
+
+	_, err = l.runCommand("helm", "env")
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+type KubeContext struct {
+	IsCurrent bool
+	Name      string
+	Cluster   string
+	AuthInfo  string
+	Namespace string
+}
+
+func (l *DataLayer) ListContexts() (res []KubeContext, err error) {
+	out, err := l.runCommand("kubectl", "config", "get-contexts")
+	if err != nil {
+		return nil, err
+	}
+
+	// kubectl has no JSON output for it, we'll have to do custom text parsing
+	lines := strings.Split(out, "\n")
+
+	// find field positions
+	fields := regexp.MustCompile(`(\w+\s+)`).FindAllString(lines[0], -1)
+	cur := len(fields[0])
+	name := cur + len(fields[1])
+	cluster := name + len(fields[2])
+	auth := cluster + len(fields[3])
+
+	// read items
+	for _, line := range lines[1:] {
+		if strings.TrimSpace(line) == "" {
+			continue
+		}
+
+		res = append(res, KubeContext{
+			IsCurrent: strings.TrimSpace(line[0:cur]) == "*",
+			Name:      strings.TrimSpace(line[cur:name]),
+			Cluster:   strings.TrimSpace(line[name:cluster]),
+			AuthInfo:  strings.TrimSpace(line[cluster:auth]),
+			Namespace: strings.TrimSpace(line[auth:]),
+		})
+	}
+
+	return res, nil
+}
+
+// unpleasant copy from Helm sources, where they have it non-public
+type releaseElement struct {
+	Name       string `json:"name"`
+	Namespace  string `json:"namespace"`
+	Revision   string `json:"revision"`
+	Updated    string `json:"updated"`
+	Status     string `json:"status"`
+	Chart      string `json:"chart"`
+	AppVersion string `json:"app_version"`
+}
+
+func (l *DataLayer) ListInstalled() (res []releaseElement, err error) {
+	out, err := l.runCommand("helm", "ls", "--all", "--all-namespaces", "--output", "json")
+	if err != nil {
+		return nil, err
+	}
+
+	err = json.Unmarshal([]byte(out), &res)
+	if err != nil {
+		return nil, err
+	}
+	return res, nil
 }