FEAT: (wip) Add support for regex patterns

cli/watch.go

@@ -3,6 +3,7 @@ package cli
 import (
 	"fmt"
 	"log"
+	"regexp"
 
 	"github.com/cian911/switchboard/utils"
 	"github.com/cian911/switchboard/watcher"
@@ -17,8 +18,10 @@ const (
 )
 
 var (
-	configFile string
-	ws         Watchers
+	configFile   string
+	ws           Watchers
+	regexPattern *regexp.Regexp
+	regexErr     error
 )
 
 // Watchers is a struct that contains a list of watchers.
@@ -70,11 +73,13 @@ func initCmd(runCmd cobra.Command) {
 	runCmd.PersistentFlags().StringP("ext", "e", "", "File type you want to watch for.")
 	runCmd.PersistentFlags().IntP("poll", "", 60, "Specify a polling time in seconds.")
 	runCmd.PersistentFlags().StringVar(&configFile, "config", "", "Pass an optional config file containing multiple paths to watch.")
+	runCmd.PersistentFlags().StringP("regex-pattern", "r", "", "Pass a regex pattern to watch for any files mathcing this pattern.")
 
 	viper.BindPFlag("path", runCmd.PersistentFlags().Lookup("path"))
 	viper.BindPFlag("destination", runCmd.PersistentFlags().Lookup("destination"))
 	viper.BindPFlag("ext", runCmd.PersistentFlags().Lookup("ext"))
 	viper.BindPFlag("poll", runCmd.PersistentFlags().Lookup("poll"))
+	viper.BindPFlag("regex-pattern", runCmd.PersistentFlags().Lookup("regex-pattern"))
 
 	var rootCmd = &cobra.Command{}
 	rootCmd.AddCommand(&runCmd)
@@ -114,6 +119,15 @@ func validateFlags() {
 	if !utils.ValidateFileExt(viper.GetString("ext")) {
 		log.Fatalf("Ext is not valid. A file extention should contain a '.': %s", viper.GetString("ext"))
 	}
+
+	if len(viper.GetString("regex-pattern")) > 0 {
+		// Validate regex pattern
+		regexPattern, regexErr = utils.ValidateRegexPattern(viper.GetString("regex-pattern"))
+
+		if regexErr != nil {
+			log.Fatalf("Regex pattern is not valid. Please check it again: %v", regexErr)
+		}
+	}
 }
 
 func registerMultiConsumers() {
@@ -160,6 +174,7 @@ func registerSingleConsumer() {
 		Path:        viper.GetString("path"),
 		Destination: viper.GetString("destination"),
 		Ext:         viper.GetString("ext"),
+		Pattern:     *regexPattern,
 	}
 
 	pw.Register(&pc)

event/event.go

@@ -11,6 +11,11 @@ import (
 	"github.com/cian911/switchboard/utils"
 )
 
+var ValidOperations = map[string]bool{
+	"CREATE": true,
+	"WRITE":  true,
+}
+
 // Event is a struct that holds the information for a file event
 type Event struct {
 	// File is the name of the file
@@ -72,7 +77,7 @@ func (e *Event) Move(path, file string) error {
 
 // IsValidEvent checks if the event operation and file extension is valid
 func (e *Event) IsValidEvent(ext string) bool {
-	if ext == e.Ext && e.Operation == "CREATE" || e.Operation == "WRITE" {
+	if ext == e.Ext && ValidOperations[e.Operation] {
 		return true
 	}
 

utils/utils.go

@@ -5,6 +5,7 @@ import (
 	"log"
 	"os"
 	"path/filepath"
+	"regexp"
 	"strings"
 )
 
@@ -75,3 +76,14 @@ func IsDir(path string) bool {
 
 	return false
 }
+
+// ValidateRegexPattern takes a regex pattern string as arg
+// and returns an error if invalid
+func ValidateRegexPattern(pattern string) (*regexp.Regexp, error) {
+	r, err := regexp.Compile(pattern)
+	if err != nil {
+		return nil, err
+	}
+
+	return r, nil
+}

utils/utils_test.go

@@ -133,6 +133,25 @@ func TestUtils(t *testing.T) {
 			}
 		}
 	})
+
+	t.Run("It tests ValidateRegexPattern()", func(t *testing.T) {
+		tests := []struct {
+			pattern        string
+			expectedOutput bool
+		}{
+			{`[0-9]`, true},
+			{`S[0-9]+EP[0-9]+`, true},
+			{`\\\\?m)^[0-9]{2}$`, false},
+		}
+
+		for _, tt := range tests {
+			_, err := ValidateRegexPattern(tt.pattern)
+
+			if err != nil && tt.expectedOutput != false {
+				t.Errorf("%s failed validation - Not a validate regex pattern. want=%t, got=%t", tt.pattern, tt.expectedOutput, err)
+			}
+		}
+	})
 }
 
 func setupTempDir(name string, t *testing.T) string {

watcher/watcher.go

@@ -1,9 +1,11 @@
 package watcher
 
 import (
+	"fmt"
 	"log"
 	"os"
 	"path/filepath"
+	"regexp"
 	"time"
 
 	"github.com/cian911/switchboard/event"
@@ -56,6 +58,8 @@ type PathConsumer struct {
 	Destination string
 	// File extenstion
 	Ext string
+	// Regex Pattern
+	Pattern regexp.Regexp
 }
 
 // Receive takes a path and an event operation, determines its validity
@@ -78,6 +82,17 @@ func (pc *PathConsumer) Receive(path, ev string) {
 
 	if e.IsNewDirEvent() {
 		pc.ProcessDirEvent(e)
+	} else if &pc.Pattern != nil {
+		// Check if event matches regex pattern
+		p := fmt.Sprintf(`%s/%s`, e.Path, e.File)
+		match := pc.Pattern.Match([]byte(p))
+
+		if match {
+			log.Println("Regex Pattern matched")
+			pc.Process(e)
+		} else {
+			log.Println("Regex did not match")
+		}
 	} else if e.IsValidEvent(pc.Ext) {
 		pc.Process(e)
 	}