Improve configuration

This commit allows configuration to be saved on disk (e.g after runtime
fixes, or after upcoming live configuration changes) and modifies
configuration structures directly when needed
Also added few utilities while I'm here

config.go

@@ -1,5 +1,11 @@
 package main
 
+import (
+	"io"
+
+	"github.com/BurntSushi/toml"
+)
+
 type tomlConfig struct {
 	// Depot contains configuration for the application itself
 	Depot depotConfig `toml:"depot"`
@@ -17,6 +23,9 @@ type depotConfig struct {
 
 	// Whether JSON REST API queries are allowed or not
 	APIEnabled bool `toml:"api_enabled"`
+
+	// Whether to save configuration changes done on runtime on Depot exit or not
+	SaveConfigChanges bool `toml:"save_config_changes"`
 }
 
 type repositoryInfo struct {
@@ -38,3 +47,59 @@ type repositoryInfo struct {
 	// MaxArtifactSize defines maximum deployable file size in bytes. By default it's 32 megabytes
 	MaxArtifactSize uint64 `toml:"max_artifact_size"`
 }
+
+// Validates configuration
+func (t *tomlConfig) Validate() error {
+	// Validate listen address
+	if len(t.Depot.ListenAddress) == 0 {
+		t.Depot.ListenAddress = ":5000"
+	}
+
+	ensureCopy := func(m **repositoryInfo, source *repositoryInfo) {
+		if *m == nil {
+			*m = &repositoryInfo{}
+			**m = *source
+		}
+	}
+
+	// Validate repository information
+	for n, info := range t.Repositories {
+		modified := (*repositoryInfo)(nil)
+
+		// Need to copy structs here, maps don't work like I expected :(
+		if info.MaxArtifactSize == 0 {
+			ensureCopy(&modified, &info)
+			modified.MaxArtifactSize = 32 << 20
+		}
+
+		// Work around toml library not encoding nil arrays
+		if info.Credentials == nil || len(info.Credentials) == 0 {
+			ensureCopy(&modified, &info)
+			modified.Credentials = []string{}
+		}
+
+		if info.DeployCredentials == nil || len(info.DeployCredentials) == 0 {
+			ensureCopy(&modified, &info)
+			modified.DeployCredentials = []string{}
+		}
+
+		// If entry is modified, replace
+		if modified != nil {
+			t.Repositories[n] = *modified
+		}
+	}
+
+	return nil
+}
+
+// Dumps configuration
+func (t *tomlConfig) Dump(writer io.Writer) error {
+	w := toml.NewEncoder(writer)
+	w.Indent = "    "
+	return w.Encode(t)
+}
+
+// Returns whether given repository is public or not
+func (i *repositoryInfo) IsPublic() bool {
+	return len(i.Credentials) == 0
+}

main.go

@@ -53,17 +53,14 @@ func main() {
 		panic(err)
 	}
 
-	var listenAddress string
-	if len(config.Depot.ListenAddress) > 0 {
-		listenAddress = config.Depot.ListenAddress
-	} else {
-		listenAddress = ":5000"
+	if err := config.Validate(); err != nil {
+		panic(err)
 	}
 
 	// Boot up the HTTP server
-	server := setupServer(listenAddress, config.Depot.RepositoryListing, config.Depot.APIEnabled, config.Repositories)
+	server := setupServer(config.Depot.ListenAddress, config.Depot.RepositoryListing, config.Depot.APIEnabled, config.Repositories)
 	go func() {
-		zap.L().Info("Starting HTTP server", zap.String("address", listenAddress))
+		zap.L().Info("Starting HTTP server", zap.String("address", config.Depot.ListenAddress))
 		if err := server.ListenAndServe(); err != http.ErrServerClosed {
 			zap.L().Error("Failed to serve", zap.Error(err))
 		}
@@ -80,6 +77,22 @@ func main() {
 
 	zap.L().Info("Shutting down")
 	<-ctx.Done()
+
+	if config.Depot.SaveConfigChanges {
+		zap.L().Info("Saving configuration")
+		var f *os.File
+		if f, err = os.OpenFile(configFile, os.O_CREATE|os.O_WRONLY, 0600); err != nil {
+			zap.L().Error("Failed to open config file for saving", zap.String("file", configFile), zap.Error(err))
+			goto End
+		}
+		defer f.Close()
+
+		if err := config.Dump(f); err != nil {
+			zap.L().Error("Failed to write configuration file", zap.String("file", configFile), zap.Error(err))
+		}
+	}
+
+End:
 	zap.L().Info("Bye!")
 }
 

server.go

@@ -68,7 +68,7 @@ func repositoryHandler(name string, info repositoryInfo) (http.HandlerFunc, stri
 		username, password, credsSupplied := r.BasicAuth()
 
 		// Check user access
-		accessRequiresAuth := len(info.Credentials) > 0
+		accessRequiresAuth := !info.IsPublic()
 		deployRequiresAuth := len(info.DeployCredentials) > 0
 		canAccess := !accessRequiresAuth
 		canDeploy := !deployRequiresAuth
@@ -118,12 +118,7 @@ func repositoryHandler(name string, info repositoryInfo) (http.HandlerFunc, stri
 			}
 
 			// Open PUT body stream
-			var requestBody io.ReadCloser
-			if info.MaxArtifactSize > 0 {
-				requestBody = http.MaxBytesReader(w, r.Body, int64(info.MaxArtifactSize))
-			} else {
-				requestBody = http.MaxBytesReader(w, r.Body, 32<<20)
-			}
+			requestBody := http.MaxBytesReader(w, r.Body, int64(info.MaxArtifactSize))
 
 			// Set up directories
 			filePath := filepath.Join(info.Path, file)

server_jsonapi.go

@@ -20,10 +20,10 @@ func setupJSONRoute(mux *http.ServeMux, repositories map[string]repositoryInfo)
 		w.WriteHeader(http.StatusOK)
 
 		repos := make([]publicRepositoryInfo, 0, len(repositories))
-		for n := range repositories {
+		for n, info := range repositories {
 			repos = append(repos, publicRepositoryInfo{
 				Name:   n,
-				Public: len(repositories[n].Credentials) == 0,
+				Public: info.IsPublic(),
 			})
 		}