Add automatically generated config sample

```
kubewatch config sample
```

TODO: update add/remove commands to use go-yaml-edit to perform in-place edits in the yaml file while preserving the comments.

cmd/config.go

@@ -77,6 +77,16 @@ Tests handler configs present in ~/.kubewatch.yaml by sending test messages`,
 	},
 }
 
+var configSampleCmd = &cobra.Command{
+	Use:   "sample",
+	Short: "Show a sample config file",
+	Long: `
+Print a sample config file which can be put in ~/.kubewatch.yaml`,
+	Run: func(cmd *cobra.Command, args []string) {
+		fmt.Print(config.ConfigSample)
+	},
+}
+
 var configViewCmd = &cobra.Command{
 	Use:   "view",
 	Short: "view ~/.kubewatch.yaml",
@@ -98,6 +108,7 @@ func init() {
 	configCmd.AddCommand(
 		configAddCmd,
 		configTestCmd,
+		configSampleCmd,
 		configViewCmd,
 	)
 

config/config.go

@@ -14,6 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+//go:generate bash -c "go install ../tools/yannotated && yannotated -o sample.go -format go -package config -type Config"
+
 package config
 
 import (
@@ -25,8 +27,13 @@ import (
 	"gopkg.in/yaml.v3"
 )
 
-// ConfigFileName stores file of config
-var ConfigFileName = ".kubewatch.yaml"
+var (
+	// ConfigFileName stores file of config
+	ConfigFileName = ".kubewatch.yaml"
+
+	// ConfigSample is a sample configuration file.
+	ConfigSample = yannotated
+)
 
 // Handler contains handler configuration
 type Handler struct {
@@ -60,26 +67,37 @@ type Resource struct {
 
 // Config struct contains kubewatch configuration
 type Config struct {
+	// Handlers know how to send notifications to specific services.
 	Handler Handler `json:"handler"`
+
 	//Reason   []string `json:"reason"`
+
+	// Resources to watch.
 	Resource Resource `json:"resource"`
-	// for watching specific namespace, leave it empty for watching all.
+
+	// For watching specific namespace, leave it empty for watching all.
 	// this config is ignored when watching namespaces
 	Namespace string `json:"namespace,omitempty"`
 }
 
 // Slack contains slack configuration
 type Slack struct {
-	Token   string `json:"token"`
+	// Slack "legacy" API token.
+	Token string `json:"token"`
+	// Slack channel.
 	Channel string `json:"channel"`
-	Title   string `json:"title"`
+	// Title of the message.
+	Title string `json:"title"`
 }
 
 // Hipchat contains hipchat configuration
 type Hipchat struct {
+	// Hipchat token.
 	Token string `json:"token"`
-	Room  string `json:"room"`
-	Url   string `json:"url"`
+	// Room name.
+	Room string `json:"room"`
+	// URL of the hipchat server.
+	Url string `json:"url"`
 }
 
 // Mattermost contains mattermost configuration
@@ -91,36 +109,51 @@ type Mattermost struct {
 
 // Flock contains flock configuration
 type Flock struct {
+	// URL of the flock API.
 	Url string `json:"url"`
 }
 
 // Webhook contains webhook configuration
 type Webhook struct {
+	// Webhook URL.
 	Url string `json:"url"`
 }
 
 // MSTeams contains MSTeams configuration
 type MSTeams struct {
+	// MSTeams API Webhook URL.
 	WebhookURL string `json:"webhookurl"`
 }
 
 // SMTP contains SMTP configuration.
 type SMTP struct {
-	To         string            `json:"to" yaml:"to,omitempty"`
-	From       string            `json:"from" yaml:"from,omitempty"`
-	Hello      string            `json:"hello" yaml:"hello,omitempty"`
-	Smarthost  string            `json:"smarthost" yaml:"smarthost,omitempty"`
-	Subject    string            `json:"subject" yaml:"subject,omitempty"`
-	Headers    map[string]string `json:"headers" yaml:"headers,omitempty"`
-	Auth       SMTPAuth          `json:"auth" yaml:"auth,omitempty"`
-	RequireTLS bool              `json:"requireTLS" yaml:"requireTLS"`
+	// Destination e-mail address.
+	To string `json:"to" yaml:"to,omitempty"`
+	// Sender e-mail address .
+	From string `json:"from" yaml:"from,omitempty"`
+	// Smarthost, aka "SMTP server"; address of server used to send email.
+	Smarthost string `json:"smarthost" yaml:"smarthost,omitempty"`
+	// Subject of the outgoing emails.
+	Subject string `json:"subject" yaml:"subject,omitempty"`
+	// Extra e-mail headers to be added to all outgoing messages.
+	Headers map[string]string `json:"headers" yaml:"headers,omitempty"`
+	// Authentication parameters.
+	Auth SMTPAuth `json:"auth" yaml:"auth,omitempty"`
+	// If "true" forces secure SMTP protocol (AKA StartTLS).
+	RequireTLS bool `json:"requireTLS" yaml:"requireTLS"`
+	// SMTP hello field (optional)
+	Hello string `json:"hello" yaml:"hello,omitempty"`
 }
 
 type SMTPAuth struct {
+	// Username for PLAN and LOGIN auth mechanisms.
 	Username string `json:"username" yaml:"username,omitempty"`
+	// Password for PLAIN and LOGIN auth mechanisms.
 	Password string `json:"password" yaml:"password,omitempty"`
-	Secret   string `json:"secret" yaml:"secret,omitempty"`
+	// Identity for PLAIN auth mechanism
 	Identity string `json:"identity" yaml:"identity,omitempty"`
+	// Secret for CRAM-MD5 auth mechanism
+	Secret string `json:"secret" yaml:"secret,omitempty"`
 }
 
 // New creates new config object

config/sample.go

@@ -0,0 +1,77 @@
+package config
+
+var yannotated = `# Handlers know how to send notifications to specific services.
+handler:
+  slack:
+    # Slack "legacy" API token.
+    token: ""
+    # Slack channel.
+    channel: ""
+    # Title of the message.
+    title: ""
+  hipchat:
+    # Hipchat token.
+    token: ""
+    # Room name.
+    room: ""
+    # URL of the hipchat server.
+    url: ""
+  mattermost:
+    room: ""
+    url: ""
+    username: ""
+  flock:
+    # URL of the flock API.
+    url: ""
+  webhook:
+    # Webhook URL.
+    url: ""
+  msteams:
+    # MSTeams API Webhook URL.
+    webhookurl: ""
+  smtp:
+    # Destination e-mail address.
+    to: ""
+    # Sender e-mail address .
+    from: ""
+    # Smarthost, aka "SMTP server"; address of server used to send email.
+    smarthost: ""
+    # Subject of the outgoing emails.
+    subject: ""
+    # Extra e-mail headers to be added to all outgoing messages.
+    headers: {}
+    # Authentication parameters.
+    auth:
+      # Username for PLAN and LOGIN auth mechanisms.
+      username: ""
+      # Password for PLAIN and LOGIN auth mechanisms.
+      password: ""
+      # Identity for PLAIN auth mechanism
+      identity: ""
+      # Secret for CRAM-MD5 auth mechanism
+      secret: ""
+    # If "true" forces secure SMTP protocol (AKA StartTLS).
+    requireTLS: false
+    # SMTP hello field (optional)
+    hello: ""
+# Resources to watch.
+resource:
+  deployment: false
+  rc: false
+  rs: false
+  ds: false
+  svc: false
+  po: false
+  job: false
+  node: false
+  clusterrole: false
+  sa: false
+  pv: false
+  ns: false
+  secret: false
+  configmap: false
+  ing: false
+# For watching specific namespace, leave it empty for watching all.
+# this config is ignored when watching namespaces
+namespace: ""
+`

go.mod

@@ -3,6 +3,7 @@ module github.com/bitnami-labs/kubewatch
 go 1.14
 
 require (
+	github.com/fatih/structtag v1.2.0
 	github.com/fsnotify/fsnotify v1.4.9 // indirect
 	github.com/golang/groupcache v0.0.0-20200121045136-8c9f03a8e57e // indirect
 	github.com/golang/protobuf v1.4.2 // indirect
@@ -15,6 +16,7 @@ require (
 	github.com/mkmik/multierror v0.3.0
 	github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e // indirect
 	github.com/pelletier/go-toml v1.0.1 // indirect
+	github.com/segmentio/textio v1.2.0
 	github.com/sirupsen/logrus v1.6.0
 	github.com/slack-go/slack v0.6.5
 	github.com/spf13/cast v1.1.0 // indirect

go.sum

@@ -22,6 +22,8 @@ github.com/docker/spdystream v0.0.0-20160310174837-449fdfce4d96/go.mod h1:Qh8CwZ
 github.com/elazarl/goproxy v0.0.0-20170405201442-c4fc26588b6e/go.mod h1:/Zj4wYkgs4iZTTu3o/KG3Itv/qCCa8VVMlb3i9OVuzc=
 github.com/emicklei/go-restful v0.0.0-20170410110728-ff4f55a20633/go.mod h1:otzb+WCGbkyDHkqmQmT5YD2WR4BBwUdeQoFo8l/7tVs=
 github.com/evanphx/json-patch v4.2.0+incompatible/go.mod h1:50XU6AFN0ol/bzJsmQLiYLvXMP4fmwYFNcr97nuDLSk=
+github.com/fatih/structtag v1.2.0 h1:/OdNE99OxoI/PqaW/SuSK9uxxT3f/tcSZgon/ssNSx4=
+github.com/fatih/structtag v1.2.0/go.mod h1:mBJUNpUnHmRKrKlQQlmCrh5PuhftFbNv8Ys4/aAZl94=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
 github.com/fsnotify/fsnotify v1.4.9 h1:hsms1Qyu0jgnwNXIxa+/V/PDsU6CfLf6CNO8H7IWoS4=
 github.com/fsnotify/fsnotify v1.4.9/go.mod h1:znqG4EE+3YCdAaPaxE2ZRY/06pZUdp0tY4IgpuI1SZQ=
@@ -114,6 +116,8 @@ github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINE
 github.com/pmezard/go-difflib v0.0.0-20151028094244-d8ed2627bdf0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/segmentio/textio v1.2.0 h1:Ug4IkV3kh72juJbG8azoSBlgebIbUUxVNrfFcKHfTSQ=
+github.com/segmentio/textio v1.2.0/go.mod h1:+Rb7v0YVODP+tK5F7FD9TCkV7gOYx9IgLHWiqtvY8ag=
 github.com/sirupsen/logrus v1.6.0/go.mod h1:7uNnSEd1DgxDLC74fIahvMZmmYsHGZGEOFrfsX/uA88=
 github.com/slack-go/slack v0.6.5 h1:IkDKtJ2IROJNoe3d6mW870/NRKvq2fhLB/Q5XmzWk00=
 github.com/slack-go/slack v0.6.5/go.mod h1:FGqNzJBmxIsZURAxh2a8D21AnOVvvXZvGligs4npPUM=