Add select context

.github/workflows/e2e.yml

@@ -49,6 +49,13 @@ jobs:
           layerform config set-context test-cloud -t cloud --url https://demo.layerform.dev --email [email protected] --password strongpass
           layerform config set-context test-local -t local --dir test
 
+      - name: layerform config set-context
+        run: |
+          # fails if command succeeds
+          ! layerform config select-context test-does-not-exist # context does not exist
+
+          layerform config set-context test-local -t local --dir test && layerform config select-context test-local
+
       - name: Configure
         run: |
           layerform configure --file examples/local/layerform.json

cmd/cli/select_context.go

@@ -0,0 +1,55 @@
+package cli
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/ergomake/layerform/internal/lfconfig"
+	"github.com/pkg/errors"
+	"github.com/spf13/cobra"
+)
+
+func init() {
+	configCmd.AddCommand(configSelectContextCmd)
+}
+
+var configSelectContextCmd = &cobra.Command{
+	Use:   "select-context <name>",
+	Short: "Select a context entry from layerform config file",
+	Long: `Select a context entry from layerform config file.
+	
+  Selecting a name that does not exist will return error.`,
+	Example: `# Select a context
+layerform config select-context local-example`,
+	Args: cobra.ExactArgs(1),
+	Run: func(cmd *cobra.Command, args []string) {
+		name := args[0]
+
+		cfg, err := lfconfig.Load("")
+		if err != nil && !errors.Is(err, os.ErrNotExist) {
+			fmt.Fprintf(os.Stderr, "%s\n", errors.Wrap(err, "fail to open config file"))
+			os.Exit(1)
+		}
+
+		_, ok := cfg.Contexts[name]
+		if !ok {
+			fmt.Fprintf(
+				os.Stderr,
+				"context %s does not exist\n",
+				name,
+			)
+			os.Exit(1)
+		}
+
+		cfg.CurrentContext = name
+
+		err = cfg.Save()
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "%s\n", errors.Wrap(err, "fail to save config file"))
+			os.Exit(1)
+		}
+
+		fmt.Fprintf(os.Stdout, "Context \"%s\" selected.\n", name)
+	},
+	SilenceErrors: true,
+}