Add a new generator config to change PrinterColumn sort function (#83)

Issue aws-controllers-k8s/community#823

This patch introduce a new generator configuration under resource
configuration, mainly to tune the `kubebuilder:printcolumn` marker
comments generation.

More precisely we add `PrintConfig` struct that contains one field
called `OrderBy` used to intruct the code generator how to sort the
`kubebuilder:printcolumn` marker comments.

e.g configuration:
```yaml
resources:
  Deployment:
    print:
      order_by: JSONPath
```

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Author: a-hilaly

pkg/generate/config/resource.go

@@ -76,6 +76,9 @@ type ResourceConfig struct {
 	// If set to false, the user will be given an error if they attempt to adopt a resource
 	// with this type.
 	IsAdoptable *bool `json:"is_adoptable,omitempty"`
+	// Print contains instructions for the code generator to generate kubebuilder printcolumns
+	// marker comments.
+	Print *PrintConfig `json:"print,omitempty"`
 }
 
 // HooksConfig instructs the code generator how to inject custom callback hooks
@@ -249,6 +252,13 @@ type UpdateOperationConfig struct {
 	CustomMethodName string `json:"custom_method_name"`
 }
 
+// PrintConfig informs instruct the code generator on how to sort kubebuilder
+// printcolumn marker coments.
+type PrintConfig struct {
+	// OrderBy is the field used to sort the list of PrinterColumn options.
+	OrderBy string `json:"order_by"`
+}
+
 // ResourceConfig returns the ResourceConfig for a given named resource
 func (c *Config) ResourceConfig(name string) (*ResourceConfig, bool) {
 	rc, ok := c.Resources[name]
@@ -403,3 +413,18 @@ func (c *Config) ResourceIsAdoptable(resourceName string) bool {
 	}
 	return *rConfig.IsAdoptable
 }
+
+// GetResourcePrintOrderByName returns the Printer Column order-by field name
+func (c *Config) GetResourcePrintOrderByName(resourceName string) string {
+	if c == nil {
+		return ""
+	}
+	rConfig, ok := c.Resources[resourceName]
+	if !ok {
+		return ""
+	}
+	if rConfig.Print != nil {
+		return rConfig.Print.OrderBy
+	}
+	return ""
+}

pkg/generate/testdata/models/apis/codedeploy/0000-00-00/generator.yaml

@@ -1,5 +1,7 @@
 resources:
   Deployment:
+    print:
+      order_by: jsonpath
     exceptions:
       errors:
         404:

pkg/model/crd.go

@@ -417,6 +417,15 @@ func (r *CRD) IsAdoptable() bool {
 	return r.cfg.ResourceIsAdoptable(r.Names.Original)
 }
 
+// GetResourcePrintOrderByName returns the Printer Column order-by field name
+func (r *CRD) GetResourcePrintOrderByName() string {
+	orderBy := r.cfg.GetResourcePrintOrderByName(r.Names.Camel)
+	if orderBy == "" {
+		return "name"
+	}
+	return orderBy
+}
+
 // CustomUpdateMethodName returns the name of the custom resourceManager method
 // for updating the resource state, if any has been specified in the generator
 // config

pkg/model/printer_column.go

@@ -16,6 +16,7 @@ package model
 import (
 	"fmt"
 	"sort"
+	"strings"
 )
 
 // PrinterColumn represents a single field in the CRD's Spec or Status objects
@@ -59,13 +60,34 @@ func (pcs printerColumnSorter) Less(i, j int) bool {
 	return pcs.by(pcs.cols[i], pcs.cols[j])
 }
 
+// sortFunction returns a Go function used the sort the printer columns.
+func sortFunction(sortByField string) func(a, b *PrinterColumn) bool {
+	switch strings.ToLower(sortByField) {
+	//TODO(a-hially): add Priority and Order sort functions
+	case "name":
+		return func(a, b *PrinterColumn) bool {
+			return a.Name < b.Name
+		}
+	case "type":
+		return func(a, b *PrinterColumn) bool {
+			return a.Type < b.Type
+		}
+	case "jsonpath":
+		return func(a, b *PrinterColumn) bool {
+			return a.JSONPath < b.JSONPath
+		}
+	default:
+		msg := fmt.Sprintf("unknown sort-by field: '%s'. must be one of 'Name', 'Type' and 'JSONPath'", sortByField)
+		panic(msg)
+	}
+}
+
 // AdditionalPrinterColumns returns a sorted list of PrinterColumn structs for
 // the resource
-func (r CRD) AdditionalPrinterColumns() []*PrinterColumn {
-	byName := func(a, b *PrinterColumn) bool {
-		return a.Name < b.Name
-	}
-	By(byName).Sort(r.additionalPrinterColumns)
+func (r *CRD) AdditionalPrinterColumns() []*PrinterColumn {
+	orderByFieldName := r.GetResourcePrintOrderByName()
+	sortFn := sortFunction(orderByFieldName)
+	By(sortFn).Sort(r.additionalPrinterColumns)
 	return r.additionalPrinterColumns
 }