cmd: make config initialization more general

- move viper initialization from k3d config file to separate util
sub-package in cmd/
- use that new subpackage init function to leverage the config file in
`k3d cluster delete`
- cover that with an e2e test case

cmd/cluster/clusterCreate.go

@@ -24,9 +24,7 @@ package cluster
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
-	"path/filepath"
 	"runtime"
 	"strconv"
 	"strings"
@@ -40,6 +38,7 @@ import (
 	"gopkg.in/yaml.v2"
 
 	cliutil "github.com/rancher/k3d/v4/cmd/util"
+	cliconfig "github.com/rancher/k3d/v4/cmd/util/config"
 	k3dCluster "github.com/rancher/k3d/v4/pkg/client"
 	"github.com/rancher/k3d/v4/pkg/config"
 	conf "github.com/rancher/k3d/v4/pkg/config/v1alpha3"
@@ -59,74 +58,30 @@ Every cluster will consist of one or more containers:
 	- (optionally) 1 (or more) agent node containers (k3s)
 `
 
-var cfgViper = viper.New()
+/*
-var ppViper = viper.New()
+ * Viper for configuration handling
+ * we use two different instances of Viper here to handle
+ * - cfgViper: "static" configuration
+ * - ppViper: "pre-processed" configuration, where CLI input has to be pre-processed
+ *             to be treated as part of the SImpleConfig
+ */
+var (
+	cfgViper = viper.New()
+	ppViper  = viper.New()
+)
 
-func initConfig() {
+func initConfig() error {
 
 	// Viper for pre-processed config options
 	ppViper.SetEnvPrefix("K3D")
 
-	// viper for the general config (file, env and non pre-processed flags)
-	cfgViper.SetEnvPrefix("K3D")
-	cfgViper.AutomaticEnv()
-
-	cfgViper.SetConfigType("yaml")
-
-	// Set config file, if specified
-	if configFile != "" {
-
-		if _, err := os.Stat(configFile); err != nil {
-			l.Log().Fatalf("Failed to stat config file %s: %+v", configFile, err)
-		}
-
-		// create temporary file to expand environment variables in the config without writing that back to the original file
-		// we're doing it here, because this happens just before absolutely all other processing
-		tmpfile, err := os.CreateTemp(os.TempDir(), fmt.Sprintf("k3d-config-tmp-%s", filepath.Base(configFile)))
-		if err != nil {
-			l.Log().Fatalf("error creating temp copy of configfile %s for variable expansion: %v", configFile, err)
-		}
-		defer tmpfile.Close()
-
-		originalcontent, err := ioutil.ReadFile(configFile)
-		if err != nil {
-			l.Log().Fatalf("error reading config file %s: %v", configFile, err)
-		}
-		expandedcontent := os.ExpandEnv(string(originalcontent))
-		if _, err := tmpfile.WriteString(expandedcontent); err != nil {
-			l.Log().Fatalf("error writing expanded config file contents to temp file %s: %v", tmpfile.Name(), err)
-		}
-
-		// use temp file with expanded variables
-		cfgViper.SetConfigFile(tmpfile.Name())
-
-		// try to read config into memory (viper map structure)
-		if err := cfgViper.ReadInConfig(); err != nil {
-			if _, ok := err.(viper.ConfigFileNotFoundError); ok {
-				l.Log().Fatalf("Config file %s not found: %+v", configFile, err)
-			}
-			// config file found but some other error happened
-			l.Log().Fatalf("Failed to read config file %s: %+v", configFile, err)
-		}
-
-		schema, err := config.GetSchemaByVersion(cfgViper.GetString("apiVersion"))
-		if err != nil {
-			l.Log().Fatalf("Cannot validate config file %s: %+v", configFile, err)
-		}
-
-		if err := config.ValidateSchemaFile(configFile, schema); err != nil {
-			l.Log().Fatalf("Schema Validation failed for config file %s: %+v", configFile, err)
-		}
-
-		l.Log().Infof("Using config file %s (%s#%s)", configFile, strings.ToLower(cfgViper.GetString("apiVersion")), strings.ToLower(cfgViper.GetString("kind")))
-	}
 	if l.Log().GetLevel() >= logrus.DebugLevel {
-		c, _ := yaml.Marshal(cfgViper.AllSettings())
-		l.Log().Debugf("Configuration:\n%s", c)
 
-		c, _ = yaml.Marshal(ppViper.AllSettings())
+		c, _ := yaml.Marshal(ppViper.AllSettings())
 		l.Log().Debugf("Additional CLI Configuration:\n%s", c)
 	}
+
+	return cliconfig.InitViperWithConfigFile(cfgViper, configFile)
 }
 
 // NewCmdClusterCreate returns a new cobra command
@@ -139,8 +94,7 @@ func NewCmdClusterCreate() *cobra.Command {
 		Long:  clusterCreateDescription,
 		Args:  cobra.RangeArgs(0, 1), // exactly one cluster name can be set (default: k3d.DefaultClusterName)
 		PreRunE: func(cmd *cobra.Command, args []string) error {
-			initConfig()
+			return initConfig()
-			return nil
 		},
 		Run: func(cmd *cobra.Command, args []string) {
 

cmd/cluster/clusterDelete.go

@@ -27,6 +27,7 @@ import (
 	"path"
 
 	"github.com/rancher/k3d/v4/cmd/util"
+	cliconfig "github.com/rancher/k3d/v4/cmd/util/config"
 	"github.com/rancher/k3d/v4/pkg/client"
 	l "github.com/rancher/k3d/v4/pkg/logger"
 	"github.com/rancher/k3d/v4/pkg/runtimes"
@@ -34,8 +35,12 @@ import (
 	k3dutil "github.com/rancher/k3d/v4/pkg/util"
 
 	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
 )
 
+var clusterDeleteConfigFile string
+var clusterDeleteCfgViper = viper.New()
+
 // NewCmdClusterDelete returns a new cobra command
 func NewCmdClusterDelete() *cobra.Command {
 
@@ -47,6 +52,9 @@ func NewCmdClusterDelete() *cobra.Command {
 		Long:              `Delete cluster(s).`,
 		Args:              cobra.MinimumNArgs(0), // 0 or n arguments; 0 = default cluster name
 		ValidArgsFunction: util.ValidArgsAvailableClusters,
+		PreRunE: func(cmd *cobra.Command, args []string) error {
+			return cliconfig.InitViperWithConfigFile(clusterDeleteCfgViper, clusterDeleteConfigFile)
+		},
 		Run: func(cmd *cobra.Command, args []string) {
 			clusters := parseDeleteClusterCmd(cmd, args)
 
@@ -87,6 +95,15 @@ func NewCmdClusterDelete() *cobra.Command {
 	// add flags
 	cmd.Flags().BoolP("all", "a", false, "Delete all existing clusters")
 
+	/***************
+	 * Config File *
+	 ***************/
+
+	cmd.Flags().StringVarP(&clusterDeleteConfigFile, "config", "c", "", "Path of a config file to use")
+	if err := cmd.MarkFlagFilename("config", "yaml", "yml"); err != nil {
+		l.Log().Fatalln("Failed to mark flag 'config' as filename flag")
+	}
+
 	// done
 	return cmd
 }
@@ -94,12 +111,36 @@ func NewCmdClusterDelete() *cobra.Command {
 // parseDeleteClusterCmd parses the command input into variables required to delete clusters
 func parseDeleteClusterCmd(cmd *cobra.Command, args []string) []*k3d.Cluster {
 
-	// --all
 	var clusters []*k3d.Cluster
 
-	if all, err := cmd.Flags().GetBool("all"); err != nil {
+	// --all
+	all, err := cmd.Flags().GetBool("all")
+	if err != nil {
 		l.Log().Fatalln(err)
-	} else if all {
+	}
+
+	// --config
+	if clusterDeleteConfigFile != "" {
+		// not allowed with --all or more args
+		if len(args) > 0 || all {
+			l.Log().Fatalln("failed to delete cluster: cannot use `--config` flag with additional arguments or `--all`")
+		}
+
+		if clusterDeleteCfgViper.GetString("name") == "" {
+			l.Log().Fatalln("failed to delete cluster via config file: no name in config file")
+		}
+
+		c, err := client.ClusterGet(cmd.Context(), runtimes.SelectedRuntime, &k3d.Cluster{Name: clusterDeleteCfgViper.GetString("name")})
+		if err != nil {
+			l.Log().Fatalf("failed to delete cluster '%s': %v", clusterDeleteCfgViper.GetString("name"), err)
+		}
+
+		clusters = append(clusters, c)
+		return clusters
+	}
+
+	// --all was set
+	if all {
 		l.Log().Infoln("Deleting all clusters...")
 		clusters, err = client.ClusterList(cmd.Context(), runtimes.SelectedRuntime)
 		if err != nil {
@@ -108,6 +149,7 @@ func parseDeleteClusterCmd(cmd *cobra.Command, args []string) []*k3d.Cluster {
 		return clusters
 	}
 
+	// args only
 	clusternames := []string{k3d.DefaultClusterName}
 	if len(args) != 0 {
 		clusternames = args

cmd/util/config/config.go

@@ -0,0 +1,98 @@
+/*
+Copyright © 2020-2021 The k3d Author(s)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+package config
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/rancher/k3d/v4/pkg/config"
+	l "github.com/rancher/k3d/v4/pkg/logger"
+	"github.com/sirupsen/logrus"
+	"github.com/spf13/viper"
+	"gopkg.in/yaml.v2"
+)
+
+func InitViperWithConfigFile(cfgViper *viper.Viper, configFile string) error {
+
+	// viper for the general config (file, env and non pre-processed flags)
+	cfgViper.SetEnvPrefix("K3D")
+	cfgViper.AutomaticEnv()
+
+	cfgViper.SetConfigType("yaml")
+
+	// Set config file, if specified
+	if configFile != "" {
+
+		if _, err := os.Stat(configFile); err != nil {
+			l.Log().Fatalf("Failed to stat config file %s: %+v", configFile, err)
+		}
+
+		// create temporary file to expand environment variables in the config without writing that back to the original file
+		// we're doing it here, because this happens just before absolutely all other processing
+		tmpfile, err := os.CreateTemp(os.TempDir(), fmt.Sprintf("k3d-config-tmp-%s", filepath.Base(configFile)))
+		if err != nil {
+			l.Log().Fatalf("error creating temp copy of configfile %s for variable expansion: %v", configFile, err)
+		}
+		defer tmpfile.Close()
+
+		originalcontent, err := ioutil.ReadFile(configFile)
+		if err != nil {
+			l.Log().Fatalf("error reading config file %s: %v", configFile, err)
+		}
+		expandedcontent := os.ExpandEnv(string(originalcontent))
+		if _, err := tmpfile.WriteString(expandedcontent); err != nil {
+			l.Log().Fatalf("error writing expanded config file contents to temp file %s: %v", tmpfile.Name(), err)
+		}
+
+		// use temp file with expanded variables
+		cfgViper.SetConfigFile(tmpfile.Name())
+
+		// try to read config into memory (viper map structure)
+		if err := cfgViper.ReadInConfig(); err != nil {
+			if _, ok := err.(viper.ConfigFileNotFoundError); ok {
+				l.Log().Fatalf("Config file %s not found: %+v", configFile, err)
+			}
+			// config file found but some other error happened
+			l.Log().Fatalf("Failed to read config file %s: %+v", configFile, err)
+		}
+
+		schema, err := config.GetSchemaByVersion(cfgViper.GetString("apiVersion"))
+		if err != nil {
+			l.Log().Fatalf("Cannot validate config file %s: %+v", configFile, err)
+		}
+
+		if err := config.ValidateSchemaFile(configFile, schema); err != nil {
+			l.Log().Fatalf("Schema Validation failed for config file %s: %+v", configFile, err)
+		}
+
+		l.Log().Infof("Using config file %s (%s#%s)", configFile, strings.ToLower(cfgViper.GetString("apiVersion")), strings.ToLower(cfgViper.GetString("kind")))
+	}
+	if l.Log().GetLevel() >= logrus.DebugLevel {
+		c, _ := yaml.Marshal(cfgViper.AllSettings())
+		l.Log().Debugf("Configuration:\n%s", c)
+	}
+	return nil
+}

tests/test_config_file.sh

@@ -17,13 +17,16 @@ fi
 
 export CURRENT_STAGE="Test | config-file | $K3S_IMAGE_TAG"
 
-
+configfileoriginal="$CURR_DIR/assets/config_test_simple.yaml"
+configfile="/tmp/config_test_simple-tmp_$(date -u +'%Y%m%dT%H%M%SZ').yaml"
 clustername="configtest"
 
+sed -E "s/name:.+/name: $clustername/g" < "$configfileoriginal" > "$configfile" # replace cluster name in config file so we can use it in this script without running into override issues
+
 highlight "[START] ConfigTest $EXTRA_TITLE"
 
 info "Creating cluster $clustername..."
-$EXE cluster create "$clustername" --config "$CURR_DIR/assets/config_test_simple.yaml" $EXTRA_FLAG || failed "could not create cluster $clustername $EXTRA_TITLE"
+$EXE cluster create "$clustername" --config "$configfile" $EXTRA_FLAG || failed "could not create cluster $clustername $EXTRA_TITLE"
 
 info "Sleeping for 5 seconds to give the cluster enough time to get ready..."
 sleep 5
@@ -60,8 +63,10 @@ exec_in_node "k3d-$clustername-server-0" "cat /etc/rancher/k3s/registries.yaml"
 
 # Cleanup
 
-info "Deleting cluster $clustername..."
+info "Deleting cluster $clustername (using config file)..."
-$EXE cluster delete "$clustername" || failed "could not delete the cluster $clustername"
+$EXE cluster delete --config "$configfile" || failed "could not delete the cluster $clustername"
+
+rm "$configfile"
 
 highlight "[DONE] ConfigTest $EXTRA_TITLE"