Add Marker support to process markers and generate code

cmd/accessor/common.go

@@ -0,0 +1,49 @@
+/*
+Copyright © 2021 Accessor Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+package main
+
+import (
+	"github.com/procyon-projects/marker"
+	"log"
+)
+
+// printErrors prints error(s) if any error exists after processing markers.
+func printErrors(errorList marker.ErrorList) {
+	if errorList == nil || len(errorList) == 0 {
+		return
+	}
+
+	for _, err := range errorList {
+		switch typedErr := err.(type) {
+		case marker.ParserError:
+			pos := typedErr.Position
+			log.Errorf("%s (%d:%d) : %s\n", typedErr.FileName, pos.Line, pos.Column, typedErr.Error())
+		case marker.ErrorList:
+			printErrors(typedErr)
+		}
+	}
+}
+
+// validateMarkers visits all files and returns errors
+func validateMarkers(collector *marker.Collector, pkgs []*marker.Package) error {
+	marker.EachFile(collector, pkgs, func(file *marker.File, fileErrors error) {
+		if fileErrors != nil {
+			validationErrors = append(validationErrors, fileErrors)
+		}
+	})
+
+	return marker.NewErrorList(validationErrors)
+}

cmd/accessor/constants.go

@@ -0,0 +1,22 @@
+/*
+Copyright © 2021 Accessor Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+package main
+
+const (
+	AppName    = "accessor"
+	AppVersion = "1.0.0"
+	PkgId      = "github.com/procyon-projects/accessor"
+)

cmd/accessor/generate.go

@@ -0,0 +1,88 @@
+/*
+Copyright © 2021 Accessor Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+package main
+
+import (
+	"github.com/procyon-projects/marker"
+	"github.com/spf13/cobra"
+	"log"
+)
+
+var paths []string
+var outputPath string
+var options []string
+
+var generateCmd = &cobra.Command{
+	Use:   "generate",
+	Short: "Generate Go files by processing markers",
+	Long:  `The generate command helps your code generation process by processing markers`,
+	Run: func(cmd *cobra.Command, args []string) {
+		packages, err := marker.LoadPackages(paths...)
+
+		if err != nil {
+			log.Errorln(err)
+			return
+		}
+
+		registry := marker.NewRegistry()
+		err = RegisterDefinitions(registry)
+
+		if err != nil {
+			log.Errorln(err)
+			return
+		}
+
+		collector := marker.NewCollector(registry)
+		err = validateMarkers(collector, packages)
+
+		if err != nil {
+
+			switch typedErr := err.(type) {
+			case marker.ErrorList:
+				printErrors(typedErr)
+				return
+			}
+
+			log.Errorln(err)
+			return
+		}
+
+		err = ProcessMarkers(collector, packages)
+		if err != nil {
+			log.Errorln(err)
+		}
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(generateCmd)
+
+	generateCmd.Flags().StringSliceVarP(&paths, "path", "p", paths, "path(s) separated by comma")
+	err := generateCmd.MarkFlagRequired("path")
+
+	if err != nil {
+		panic(err)
+	}
+
+	generateCmd.Flags().StringVarP(&outputPath, "output", "o", "", "output path")
+	err = generateCmd.MarkFlagRequired("output")
+
+	if err != nil {
+		panic(err)
+	}
+
+	generateCmd.Flags().StringSliceVarP(&options, "args", "a", options, "extra arguments for marker processors (key-value separated by comma)")
+}

cmd/accessor/main.go

@@ -0,0 +1,23 @@
+/*
+Copyright © 2021 Accessor Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+package main
+
+import "log"
+
+func main() {
+	log.SetFlags(0)
+	Execute()
+}

cmd/accessor/markers.go

@@ -0,0 +1,59 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+)
+
+const (
+	MarkerAccessor        = "accessor"
+	MarkerAccessorMapping = "accessor:mapping"
+)
+
+type AccessorMarker struct {
+	Value string `marker:"Value,useValueSyntax"`
+	Url   string `marker:"Url"`
+}
+
+func (a AccessorMarker) Validate() error {
+	if strings.TrimSpace(a.Value) == "" {
+		return errors.New("'Value' cannot be empty or nil")
+	}
+
+	if strings.TrimSpace(a.Url) == "" {
+		return errors.New("'Url' cannot be empty or nil")
+	}
+
+	return nil
+}
+
+type AccessorMappingMarker struct {
+	Value  string `marker:"Value,useValueSyntax"`
+	Method string `marker:"Method"`
+}
+
+func (a AccessorMappingMarker) Validate() error {
+	if strings.TrimSpace(a.Value) == "" {
+		return errors.New("'Value' cannot be empty or nil")
+	}
+
+	if strings.TrimSpace(a.Method) == "" {
+		return errors.New("'Url' cannot be empty or nil")
+	}
+
+	matched := false
+	methods := []string{"GET", "POST", "HEAD", "OPTIONS", "PUT", "PATCH", "DELETE", "TRACE"}
+
+	for _, method := range methods {
+		if strings.TrimSpace(a.Method) == method {
+			matched = true
+		}
+	}
+
+	if !matched {
+		return fmt.Errorf("invalid 'Method' argument value. Here is the list of valid values %s", strings.Join(methods, ", "))
+	}
+
+	return nil
+}

cmd/accessor/processor.go

@@ -0,0 +1,77 @@
+/*
+Copyright © 2021 Accessor Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+package main
+
+import (
+	"github.com/procyon-projects/marker"
+)
+
+var (
+	accessorInterfaces []marker.InterfaceType
+)
+
+// Register your marker definitions.
+func RegisterDefinitions(registry *marker.Registry) error {
+	markers := []struct {
+		Name   string
+		Level  marker.TargetLevel
+		Output interface{}
+	}{
+		{Name: MarkerAccessor, Level: marker.InterfaceTypeLevel, Output: &AccessorMarker{}},
+		{Name: MarkerAccessorMapping, Level: marker.InterfaceMethodLevel, Output: &AccessorMappingMarker{}},
+	}
+
+	for _, m := range markers {
+		err := registry.Register(m.Name, PkgId, m.Level, m.Output)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// Process your markers.
+func ProcessMarkers(collector *marker.Collector, pkgs []*marker.Package) error {
+	marker.EachFile(collector, pkgs, func(file *marker.File, err error) {
+		findAccessorInterfaces(file.InterfaceTypes)
+	})
+	return nil
+}
+
+func findAccessorInterfaces(interfaceTypes []marker.InterfaceType) {
+	for _, interfaceType := range interfaceTypes {
+		markerValues := interfaceType.Markers
+
+		if markerValues == nil {
+			return
+		}
+
+		markers, ok := markerValues[MarkerAccessor]
+
+		if !ok {
+			return
+		}
+
+		for _, candidateMarker := range markers {
+			switch candidateMarker.(type) {
+			case AccessorMarker:
+				accessorInterfaces = append(accessorInterfaces, interfaceType)
+			}
+		}
+
+	}
+}

cmd/accessor/root.go

@@ -0,0 +1,31 @@
+/*
+Copyright © 2021 Accessor Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+package main
+
+import (
+	"fmt"
+	"github.com/spf13/cobra"
+)
+
+var rootCmd = &cobra.Command{
+	Use:   fmt.Sprintf(AppName),
+	Short: "Marker Processor",
+	Long:  `Marker Processor`,
+}
+
+func Execute() {
+	cobra.CheckErr(rootCmd.Execute())
+}