Allow configuration sink prefixes

docs/README.md

@@ -38,26 +38,37 @@ You'll need a `kubectl`-style config file to connect to your cluster.
 
 ## Kn Config
 
-There are a set of configuration parameters you can setup to better customize `kn`. In particular, you can specify where your `kn` plugins are located and how they are found. The `kn` configuration file is meant to capture these configuration options. Let's explore this file's location, and the options you are able to change with it.
+There are a set of configuration parameters you can setup to better customize `kn`. For example, you can specify where your `kn` plugins are located and how they are found, and you can specify the prefix for your addressable `sink` objects. The `kn` configuration file is meant to capture these configuration options. Let's explore this file's location, and the options you are able to change with it.
 
 ### Location
 
 The default location `kn` looks for config is under the home directory of the user at `$HOME/.kn/config.yaml`. It is not created for you as part of the `kn` installation. You can create this file elsewhere and use the `--config` flag to specify its path.
 
 ### Options
 
-There are two options you can specify in the `kn` config file and they are related to how `kn` locates plugins.
+Below are the options you can specify in the `kn` config file.
 
 1. `pluginsDir` which is the same as the persistent flag `--plugins-dir` and specifies the kn plugins directory. It defaults to: `~/.kn/plugins`. By using the persistent flag (when you issue a command) or by specifying the value in the `kn` config, a user can select which directory to find `kn` plugins. It can be any directory that is visible to the user.
 
 2. `lookupPluginsInPath` which is the same as the persistent flag `--lookup-plugins-in-path` and specficies if `kn` should look for plugins anywhere in the specified `PATH` environment variable. This is a boolean configuration option and the default value is `false`.
 
-For example, the following `kn` config will look for `kn` plugins in the user's `PATH` and also execute plugin in `~/.kn/plugins`.
+3. `sink` defines your prefix to refer to Kubernetes resources which are described by APIGroup, Version and KIND. Then a `sink` object could be described as `<prefix>:<object name>` in `kn` command lines.
+    1. `prefix` is the prefix you want to describe your sink objects. `svc`, `service`, and `broker` are predefined prefixes in `kn`.
+    2. `group` is the APIGroup of Kubernetes resources.
+    3. `version` is the version of Kubernetes resources.
+    4. `resource` is the plural name of Kubernetes resources. 
+
+For example, the following `kn` config will look for `kn` plugins in the user's `PATH` and also execute plugin in `~/.kn/plugins`. It also defines a sink prefix `myprefix` which refer to `brokers` in `eventing.knative.dev/v1alpha1`. With this configuration, you could use `myprefix:default` to describe Broker `default` in `kn` command lines.
 
 ```bash
 cat ~/.kn/config.yaml
 lookupPluginsInPath: true
 pluginsdir: ~/.kn/plugins
+sink:
+- prefix: myprefix
+  group: eventing.knative.dev
+  version: v1alpha1
+  resource: brokers
 ```
 ----------------------------------------------------------
 

pkg/kn/commands/flags/sink.go

@@ -25,6 +25,7 @@ import (
 	duckv1 "knative.dev/pkg/apis/duck/v1"
 
 	clientdynamic "knative.dev/client/pkg/dynamic"
+	"knative.dev/client/pkg/kn/commands"
 )
 
 type SinkFlags struct {
@@ -55,6 +56,17 @@ var SinkPrefixes = map[string]schema.GroupVersionResource{
 	},
 }
 
+func ConfigSinkPrefixes(prefixes []commands.SinkPrefixConfig) {
+	for _, p := range prefixes {
+		//user configration might override the default configuration
+		SinkPrefixes[p.Prefix] = schema.GroupVersionResource{
+			Resource: p.Resource,
+			Group:    p.Group,
+			Version:  p.Version,
+		}
+	}
+}
+
 // ResolveSink returns the Destination referred to by the flags in the acceptor.
 // It validates that any object the user is referring to exists.
 func (i *SinkFlags) ResolveSink(knclient clientdynamic.KnDynamicClient, namespace string) (*duckv1.Destination, error) {

pkg/kn/commands/types.go

@@ -48,6 +48,15 @@ var Cfg Config = Config{
 type Config struct {
 	PluginsDir    string
 	LookupPlugins *bool
+	SinkPrefixes  []SinkPrefixConfig
+}
+
+// SinkPrefixConfig is the struct of sink prefix config in kn config
+type SinkPrefixConfig struct {
+	Prefix   string
+	Resource string
+	Group    string
+	Version  string
 }
 
 // KnParams for creating commands. Useful for inserting mocks for testing.

pkg/kn/core/root.go

@@ -31,6 +31,7 @@ import (
 	_ "k8s.io/client-go/plugin/pkg/client/auth/oidc"
 	"knative.dev/client/pkg/kn/commands"
 	"knative.dev/client/pkg/kn/commands/completion"
+	cmdflags "knative.dev/client/pkg/kn/commands/flags"
 	"knative.dev/client/pkg/kn/commands/plugin"
 	"knative.dev/client/pkg/kn/commands/revision"
 	"knative.dev/client/pkg/kn/commands/route"
@@ -234,6 +235,15 @@ func initConfigFlags() {
 	var aBool bool
 	aBool = viper.GetBool("lookup-plugins")
 	commands.Cfg.LookupPlugins = &aBool
+
+	// set the Cfg.SinkPrefixes from viper if sink is configured
+	if viper.IsSet("sink") {
+		err := viper.UnmarshalKey("sink", &commands.Cfg.SinkPrefixes)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Unable to parse sink prefixes configuration: %v .\n", err)
+		}
+		cmdflags.ConfigSinkPrefixes(commands.Cfg.SinkPrefixes)
+	}
 }
 
 func extractKnPluginFlags(args []string) (string, bool, error) {