cmd/stepd: Configuration file is read and used for the HTTP server

Closes #7

cmd/stepd/main.go

@@ -4,6 +4,7 @@ package main
 import "os"
 import "log"
 import "time"
+import "slices"
 import "errors"
 import "context"
 import "net/http"
@@ -16,30 +17,30 @@ import "git.tebibyte.media/sashakoshka/go-service/daemon"
 import stephttp"git.tebibyte.media/sashakoshka/step/http"
 import "git.tebibyte.media/sashakoshka/go-service/routines"
 
+const configFileName = "step.meta"
+
 func main () {
 	// parse command line arguments
 	flagPidFile := cli.NewInputFlag (
 		'p', "pid-file",
 		"Write the PID to the specified file.",
 		"", cli.ValString)
-	flagAddress := cli.NewInputFlag (
-		'a', "address",
-		"The address to host the server on.",
+	flagHTTPAddress := cli.NewInputFlag (
+		'h', "http-address",
+		"The address to host the HTTP server on.",
 		":8080", cli.ValString)
-	// TODO have in conf, override here
-	flagErrorDocument := cli.NewInputFlag (
-		0, "error-document",
-		"The document to use for displaying errors.",
+	flagHTTPErrorDocument := cli.NewInputFlag (
+		0, "http-error-document",
+		"The document to use for displaying http errors.",
 		"", cli.ValString)
-	// TODO have in conf, override here
 	flagDirectories := cli.NewFlag (
 		'd', "directories",
 		"Serve the contents of directories.")
 	cmd := cli.New (
 		"Run an HTTP server that automaticaly executes STEP files.",
 		flagPidFile,
-		flagAddress,
-		flagErrorDocument,
+		flagHTTPAddress,
+		flagHTTPErrorDocument,
 		flagDirectories,
 		cli.NewHelp())
 	cmd.Syntax = "[OPTIONS]... [DIRECTORY]"
@@ -51,6 +52,7 @@ func main () {
 
 	// manage start and end of program
 	ctx, done := context.WithCancel(context.Background())
+	defer done()
 	daemon.OnSigint(done)
 	pidFileAbs, err := filepath.Abs(flagPidFile.Value)
 	if err != nil { log.Fatalln("XXX", err) }
@@ -73,9 +75,36 @@ func main () {
 		cmd.Usage()
 		os.Exit(1)
 	}
+
+	// read the config file
+	var config step.Meta
+	if configFile, err := os.Open(configFileName); err == nil {
+		defer configFile.Close()
+		config, err = step.DecodeMeta(configFile)
+		configFile.Close()
+		if err != nil { log.Fatalln("XXX", err) }
+	} else {
+		config = make(step.Meta)
+		log.Printf (
+			"(i) could not open %s, using default configuration",
+			configFileName)
+	}
+
+	// override the config file with explicitly specified options
+	if flagHTTPAddress.Value != "" {
+		config.Set("http.address", flagHTTPAddress.Value)
+	}
+	if flagHTTPErrorDocument.Value != "" {
+		config.Set("http.error-document", flagHTTPErrorDocument.Value)
+	}
+	if flagDirectories.Value != "" {
+		config.Set("http.serve-directories", flagDirectories.Value)
+	}
 	
 	// set up the environment
-	environment := step.Environment { }
+	environment := step.Environment {
+		Config: config,
+	}
 	environment.Providers = providers.All()
 	err = environment.Init(context.Background())
 	if err != nil { log.Fatal(err) }
@@ -83,20 +112,26 @@ func main () {
 	// set up the HTTP handler
 	handler := stephttp.Handler {
 		Environment:   &environment,
-		Directories:   flagDirectories.Value == "true",
-		StepExt:       ucontainer.NewSet(".step"),
-		Index:         []string { "index.step", "index.html", "index" },
-		ErrorDocument: flagErrorDocument.Value,
+		Directories:   config.Get("http.serve-directories") == "true",
+		StepExt:       ucontainer.NewSet(slices.Clone(config["http.step-extension"])...),
+		Index:         slices.Clone(config["http.index-file"]),
+		ErrorDocument: config.Get("http.error-document"),
+	}
+	if len(handler.StepExt) == 0 {
+		handler.StepExt.Add(".step")
+	}
+	if len(handler.Index) == 0 {
+		handler.Index = []string { "index.step", "index.html", "index" }
 	}
 
 	// set up the HTTP server
 	httpServer := http.Server {
-		Addr:    flagAddress.Value,
+		Addr:    config.Get("http.address"),
 		Handler: &handler,
 	}
+	httpServerRoutine := httpServerRoutine(httpServer)
 
 	// set up the routine manager
-	httpServerRoutine := httpServerRoutine(httpServer)
 	manager := routines.Manager {
 		Routines: []routines.Routine {
 			&httpServerRoutine,