separate file handling functions from main file

main.go

@@ -1,15 +1,12 @@
 package main
 
 import (
-	"crypto/sha256"
 	"encoding/json"
 	"fmt"
-	"io"
 	"io/fs"
 	"log"
 	"net/http"
 	"os"
-	"strings"
 	"sync"
 )
 
@@ -31,9 +28,9 @@ type HTTPResponseJSON struct {
 
 // Caches data about available ROMs in memory so we don't need to reference the filesystem for each request
 type ROMCache struct {
-	ROMs       []LineageOSROM  `json:"roms"`
+	ROMs         []LineageOSROM  `json:"roms"`
-	Cached     map[string]bool `json:"-"` // to quickly lookup if a file is already cached
+	Cached       map[string]bool `json:"-"` // to quickly lookup if a file is already cached
-	sync.Mutex `json:"-"`      // We have multiple goroutines that may be accessing this data simultaneously, so we much lock / unlock it to prevent race conditions
+	sync.RWMutex `json:"-"`      // We have multiple goroutines that may be accessing this data simultaneously, so we much lock / unlock it to prevent race conditions
 }
 
 const (
@@ -161,9 +158,9 @@ func updateROMCache() {
 
 	// save file to disk for next startup so we don't have to rehash all the files again
 	wg.Wait()
-	romCache.Lock()
+	romCache.RLock()
 	romCacheJson, err := json.Marshal(romCache)
-	romCache.Unlock()
+	romCache.RUnlock()
 	if err != nil {
 		log.Printf("failed to marshal romCache to json: %v", err)
 		return
@@ -181,58 +178,6 @@ func updateROMCache() {
 	}
 }
 
-// returns true if new builds were moved
-func moveBuildArtifacts() bool {
-
-	f, err := os.Open(buildOutDirectory)
-	if err != nil {
-		log.Printf("failed to open ROM directory: %v", err)
-		return false
-	}
-	defer f.Close()
-	files, err := f.ReadDir(0)
-	if err != nil {
-		log.Printf("failed to read files in directory: %v", err)
-		return false
-	}
-
-	var newROMs bool
-
-	for _, v := range files {
-		if isLineageROM, _ := isLineageROMZip(v); !isLineageROM { // skip files that aren't LineageOS ROMs
-			continue
-		}
-
-		newROMs = true
-		log.Printf("new build found - moving file %s", v.Name())
-		romCache.Lock() // lock to prevent multiple concurrent goroutines moving the same file
-		err := moveBuildFile(fmt.Sprintf("%s/%s", buildOutDirectory, v.Name()), fmt.Sprintf("%s/%s", romDirectory, v.Name()))
-		romCache.Unlock()
-		if err != nil {
-			log.Printf("failed to move file '%s' from out to rom directory: %v", v.Name(), err)
-			continue
-		}
-	}
-
-	return newROMs
-}
-
-// false if a file is not a LineageOS ROM .zip file
-// no formal validation is performed - only file naming convention is checked
-// also returns a lineage ROM's filename sliced and delimited by -'s
-// Example filename: lineage-20.0-20230604-UNOFFICIAL-sunfish.zip
-func isLineageROMZip(v fs.DirEntry) (bool, []string) {
-
-	// skip directories, non .zip files and files that don't begin with lineage-
-	if v.Type().IsDir() || !strings.HasSuffix(v.Name(), ".zip") || !strings.HasPrefix(v.Name(), "lineage-") {
-		return false, nil
-	}
-
-	splitName := strings.Split(v.Name(), "-")
-	// expect 5 dashes
-	return len(splitName) == 5, splitName
-}
-
 // http - GET /
 // Writes JSON response for the updater app to know what versions are available to download
 func lineageOSROMListHandler(w http.ResponseWriter, r *http.Request) {
@@ -256,55 +201,3 @@ func lineageOSROMListHandler(w http.ResponseWriter, r *http.Request) {
 
 	w.Write(b)
 }
-
-// Returns a sha256 hash of a file located at the path provided
-func hashFile(filename string) (string, error) {
-	f, err := os.Open(filename)
-	if err != nil {
-		return "", fmt.Errorf("failed to open file '%s': %v: ", filename, err)
-	}
-	defer f.Close()
-
-	h := sha256.New()
-	if _, err := io.Copy(h, f); err != nil {
-		return "", fmt.Errorf("failed to copy data from file to hash function: %v", err)
-	}
-
-	return fmt.Sprintf("%x", h.Sum(nil)), nil
-}
-
-// A custom "move file" function because in docker container the mounted folders are different overlay filesystems
-// Instead of os.Rename, we must copy and delete
-func moveBuildFile(src, dst string) error {
-	sourceFileStat, err := os.Stat(src)
-	if err != nil {
-		return err
-	}
-
-	if !sourceFileStat.Mode().IsRegular() {
-		return fmt.Errorf("%s is not a regular file", src)
-	}
-
-	source, err := os.Open(src)
-	if err != nil {
-		return err
-	}
-	defer source.Close()
-
-	destination, err := os.Create(dst)
-	if err != nil {
-		return err
-	}
-	defer destination.Close()
-	_, err = io.Copy(destination, source)
-	if err != nil {
-		return fmt.Errorf("failed to copy file: %v", err)
-	}
-
-	err = os.Remove(src)
-	if err != nil {
-		return fmt.Errorf("failed to delete source file after copy: %v", err)
-	}
-
-	return nil
-}

processFiles.go

@@ -0,0 +1,117 @@
+package main
+
+import (
+	"crypto/sha256"
+	"fmt"
+	"io"
+	"io/fs"
+	"log"
+	"os"
+	"strings"
+)
+
+// Searches the build toolchain output directory for new LineageOS builds.
+// Any new builds are moved into the public http server directory.
+// Returns true if new builds were moved
+func moveBuildArtifacts() bool {
+
+	f, err := os.Open(buildOutDirectory)
+	if err != nil {
+		log.Printf("failed to open ROM directory: %v", err)
+		return false
+	}
+	defer f.Close()
+	files, err := f.ReadDir(0)
+	if err != nil {
+		log.Printf("failed to read files in directory: %v", err)
+		return false
+	}
+
+	var newROMs bool
+
+	for _, v := range files {
+		if isLineageROM, _ := isLineageROMZip(v); !isLineageROM { // skip files that aren't LineageOS ROMs
+			continue
+		}
+
+		newROMs = true
+		log.Printf("new build found - moving file %s", v.Name())
+		romCache.Lock() // lock to prevent multiple concurrent goroutines moving the same file
+		err := moveBuildFile(fmt.Sprintf("%s/%s", buildOutDirectory, v.Name()), fmt.Sprintf("%s/%s", romDirectory, v.Name()))
+		romCache.Unlock()
+		if err != nil {
+			log.Printf("failed to move file '%s' from out to rom directory: %v", v.Name(), err)
+			continue
+		}
+	}
+
+	return newROMs
+}
+
+// Returns a sha256 hash of a file located at the path provided
+func hashFile(filename string) (string, error) {
+	f, err := os.Open(filename)
+	if err != nil {
+		return "", fmt.Errorf("failed to open file '%s': %v: ", filename, err)
+	}
+	defer f.Close()
+
+	h := sha256.New()
+	if _, err := io.Copy(h, f); err != nil {
+		return "", fmt.Errorf("failed to copy data from file to hash function: %v", err)
+	}
+
+	return fmt.Sprintf("%x", h.Sum(nil)), nil
+}
+
+// false if a file is not a LineageOS ROM .zip file
+// no formal validation is performed - only file naming convention is checked
+// also returns a lineage ROM's filename sliced and delimited by -'s
+// Example filename: lineage-20.0-20230604-UNOFFICIAL-sunfish.zip
+func isLineageROMZip(v fs.DirEntry) (bool, []string) {
+
+	// skip directories, non .zip files and files that don't begin with lineage-
+	if v.Type().IsDir() || !strings.HasSuffix(v.Name(), ".zip") || !strings.HasPrefix(v.Name(), "lineage-") {
+		return false, nil
+	}
+
+	splitName := strings.Split(v.Name(), "-")
+	// expect 5 dashes
+	return len(splitName) == 5, splitName
+}
+
+// A custom "move file" function because in docker container the mounted folders are different overlay filesystems
+// Instead of os.Rename, we must copy and delete
+func moveBuildFile(src, dst string) error {
+	sourceFileStat, err := os.Stat(src)
+	if err != nil {
+		return err
+	}
+
+	if !sourceFileStat.Mode().IsRegular() {
+		return fmt.Errorf("%s is not a regular file", src)
+	}
+
+	source, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer source.Close()
+
+	destination, err := os.Create(dst)
+	if err != nil {
+		return err
+	}
+	defer destination.Close()
+	_, err = io.Copy(destination, source)
+	if err != nil {
+		return fmt.Errorf("failed to copy file: %v", err)
+	}
+
+	err = os.Remove(src)
+	if err != nil {
+		return fmt.Errorf("failed to delete source file after copy: %v", err)
+	}
+
+	return nil
+}