perf(core): lazy load usage (#2700)

Author: Codelax

internal/core/cobra_builder.go

@@ -100,21 +100,25 @@ func (b *cobraBuilder) hydrateCobra(cobraCmd *cobra.Command, cmd *Command) {
 		cobraCmd.Annotations = make(map[string]string)
 	}
 
-	if cmd.ArgsType != nil {
-		cobraCmd.Annotations["UsageArgs"] = buildUsageArgs(b.ctx, cmd, false)
-	}
+	// Use a custom function to print usage
+	// This function will build usage to avoid building it for each commands
+	cobraCmd.SetUsageFunc(usageFuncBuilder(cobraCmd, func() {
+		if cmd.ArgsType != nil {
+			cobraCmd.Annotations["UsageArgs"] = buildUsageArgs(b.ctx, cmd, false)
+		}
 
-	if cmd.ArgSpecs != nil {
-		cobraCmd.Annotations["UsageDeprecatedArgs"] = buildUsageArgs(b.ctx, cmd, true)
-	}
+		if cmd.ArgSpecs != nil {
+			cobraCmd.Annotations["UsageDeprecatedArgs"] = buildUsageArgs(b.ctx, cmd, true)
+		}
 
-	if cmd.Examples != nil {
-		cobraCmd.Annotations["Examples"] = buildExamples(b.meta.BinaryName, cmd)
-	}
+		if cmd.Examples != nil {
+			cobraCmd.Annotations["Examples"] = buildExamples(b.meta.BinaryName, cmd)
+		}
 
-	if cmd.SeeAlsos != nil {
-		cobraCmd.Annotations["SeeAlsos"] = cmd.seeAlsosAsStr()
-	}
+		if cmd.SeeAlsos != nil {
+			cobraCmd.Annotations["SeeAlsos"] = cmd.seeAlsosAsStr()
+		}
+	}))
 
 	if cmd.Run != nil {
 		cobraCmd.RunE = cobraRun(b.ctx, cmd)

internal/core/cobra_usage_builder.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/scaleway/scaleway-cli/v2/internal/interactive"
 	"github.com/scaleway/scaleway-sdk-go/logger"
+	"github.com/spf13/cobra"
 )
 
 const (
@@ -100,3 +101,15 @@ func buildExamples(binaryName string, cmd *Command) string {
 	// Return a single string for all examples.
 	return strings.Join(examples, "\n\n")
 }
+
+// usageFuncBuilder returns the usage function that will be used by cobra to print usage,
+// the builder also takes a function that will fill annotations used by the usage template,
+// this is done like this to avoid build annotations for each command if not required
+func usageFuncBuilder(cmd *cobra.Command, annotationBuilder func()) func(*cobra.Command) error {
+	return func(command *cobra.Command) error {
+		annotationBuilder()
+		// after building annotation we remove this function as we prefer to use default UsageFunc
+		cmd.SetUsageFunc(nil)
+		return cmd.UsageFunc()(command)
+	}
+}