refactor: bring startup logic to entrypoint.go

cmd/run.go

@@ -1,16 +1,9 @@
 package cmd
 
 import (
-	"log"
-	"log/slog"
-	"net/http"
-	"os"
-	"runtime/trace"
-
 	"github.com/encodeous/nylon/core"
 	"github.com/encodeous/nylon/state"
 	"github.com/spf13/cobra"
-	"gopkg.in/yaml.v3"
 )
 
 import _ "net/http/pprof" // remove in stable version of nylon
@@ -21,102 +14,16 @@ var runCmd = &cobra.Command{
 	Short: "Run nylon",
 	Long:  `This will run nylon`,
 	Run: func(cmd *cobra.Command, args []string) {
-		if state.DBG_trace {
-			f, err := os.Create("trace.out")
-			if err != nil {
-				log.Fatal(err)
-			}
-			err = trace.Start(f)
-			defer trace.Stop()
-			if err != nil {
-				return
-			}
-			log.Println("Started tracing")
-		}
-		if state.DBG_pprof {
-			go func() {
-				log.Println(http.ListenAndServe("0.0.0.0:6060", nil))
-			}()
-		}
-
 		centralPath := cmd.Flag("config").Value.String()
 		nodePath := cmd.Flag("node").Value.String()
 		logPath := cmd.Flag("log").Value.String()
-	start:
-		var centralCfg state.CentralCfg
-		file, err := os.ReadFile(centralPath)
-		if err != nil {
-			if !os.IsNotExist(err) {
-				panic(err)
-			}
-			var nodeCfg state.LocalCfg
-			file, err = os.ReadFile(nodePath)
-			if err != nil {
-				panic(err)
-			}
-			err = yaml.Unmarshal(file, &nodeCfg)
-			if err != nil {
-				panic(err)
-			}
-			if nodeCfg.Dist == nil {
-				panic("central.yaml not found and node.yaml has no dist config")
-			}
-			cfg, err := core.FetchConfig(nodeCfg.Dist.Url, nodeCfg.Dist.Key)
-			if err != nil {
-				panic(err)
-			}
-			bytes, err := yaml.Marshal(cfg)
-			if err != nil {
-				panic(err)
-			}
-			err = os.WriteFile(centralPath, bytes, 0700)
-			if err != nil {
-				panic(err)
-			}
-			centralCfg = *cfg
-		} else {
-			err = yaml.Unmarshal(file, &centralCfg)
-			if err != nil {
-				panic(err)
-			}
-		}
-
-		var nodeCfg state.LocalCfg
-		file, err = os.ReadFile(nodePath)
-		if err != nil {
-			panic(err)
-		}
-		err = yaml.Unmarshal(file, &nodeCfg)
-		if err != nil {
-			panic(err)
-		}
 
-		if logPath != "" {
-			nodeCfg.LogPath = logPath
-		}
-
-		err = state.CentralConfigValidator(&centralCfg)
-		if err != nil {
-			panic(err)
-		}
-		state.ExpandCentralConfig(&centralCfg)
-		err = state.NodeConfigValidator(&nodeCfg)
-		if err != nil {
-			panic(err)
-		}
-
-		level := slog.LevelInfo
+		isVerbose := false
 		if ok, _ := cmd.Flags().GetBool("verbose"); ok {
-			level = slog.LevelDebug
+			isVerbose = true
 		}
 
-		restart, err := core.Start(centralCfg, nodeCfg, level, centralPath, nil, nil)
-		if err != nil {
-			panic(err)
-		}
-		if restart {
-			goto start
-		}
+		core.Bootstrap(centralPath, nodePath, logPath, isVerbose)
 	},
 	GroupID: "ny",
 }

core/runtime.go → core/entrypoint.go

@@ -3,20 +3,148 @@ package core
 import (
 	"context"
 	"errors"
+	"fmt"
+	"log"
 	"log/slog"
+	"net/http"
 	"os"
 	"os/signal"
 	"path"
 	"reflect"
 	"runtime"
+	"runtime/trace"
 	"syscall"
 	"time"
 
 	"github.com/encodeous/nylon/state"
 	"github.com/encodeous/tint"
 	slogmulti "github.com/samber/slog-multi"
+	"gopkg.in/yaml.v3"
 )
 
+func setupDebugging() {
+	if state.DBG_trace {
+		f, err := os.Create("trace.out")
+		if err != nil {
+			log.Fatal(err)
+		}
+		err = trace.Start(f)
+		defer trace.Stop()
+		if err != nil {
+			return
+		}
+		log.Println("Started tracing")
+	}
+	if state.DBG_pprof {
+		go func() {
+			log.Println(http.ListenAndServe("0.0.0.0:6060", nil))
+		}()
+	}
+}
+
+func readCentralConfig(centralPath, nodePath string) (*state.CentralCfg, error) {
+	var centralCfg state.CentralCfg
+
+	file, err := os.ReadFile(centralPath)
+	if err != nil {
+		if !os.IsNotExist(err) {
+			return nil, err
+		}
+		// fallback to using dist from node config
+
+		var nodeCfg state.LocalCfg
+
+		file, err = os.ReadFile(nodePath)
+		if err != nil {
+			return nil, fmt.Errorf("central.yaml not found and failed to read node.yaml: %w", err)
+		}
+
+		err = yaml.Unmarshal(file, &nodeCfg)
+		if err != nil {
+			return nil, err
+		}
+
+		if nodeCfg.Dist == nil {
+			return nil, fmt.Errorf("central.yaml not found and node.yaml has no dist config")
+		}
+
+		cfg, err := FetchConfig(nodeCfg.Dist.Url, nodeCfg.Dist.Key)
+		if err != nil {
+			return nil, err
+		}
+
+		bytes, err := yaml.Marshal(cfg)
+		if err != nil {
+			return nil, err
+		}
+		err = os.WriteFile(centralPath, bytes, 0700)
+		if err != nil {
+			return nil, err
+		}
+
+		centralCfg = *cfg
+	} else {
+		err = yaml.Unmarshal(file, &centralCfg)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return &centralCfg, nil
+}
+
+func readNodeConfig(nodePath string) (*state.LocalCfg, error) {
+	var nodeCfg state.LocalCfg
+	file, err := os.ReadFile(nodePath)
+	if err != nil {
+		return nil, err
+	}
+	err = yaml.Unmarshal(file, &nodeCfg)
+	if err != nil {
+		return nil, err
+	}
+	return &nodeCfg, nil
+}
+
+// Bootstrap manages the lifetime of the whole application. Nylon may be restarted multiple times, but Bootstrap is only called once.
+func Bootstrap(centralPath, nodePath, logPath string, verbose bool) {
+	setupDebugging()
+	level := slog.LevelInfo
+	if verbose {
+		level = slog.LevelDebug
+	}
+
+	for {
+		centralCfg, err := readCentralConfig(centralPath, nodePath)
+		if err != nil {
+			panic(err)
+		}
+		nodeCfg, err := readNodeConfig(nodePath)
+		if err != nil {
+			panic(err)
+		}
+		if logPath != "" {
+			nodeCfg.LogPath = logPath
+		}
+
+		err = state.CentralConfigValidator(centralCfg)
+		if err != nil {
+			panic(err)
+		}
+		state.ExpandCentralConfig(centralCfg)
+		err = state.NodeConfigValidator(nodeCfg)
+		if err != nil {
+			panic(err)
+		}
+		restart, err := Start(*centralCfg, *nodeCfg, level, centralPath, nil, nil)
+		if err != nil {
+			panic(err)
+		}
+		if !restart {
+			break
+		}
+	}
+}
+
 func Start(ccfg state.CentralCfg, ncfg state.LocalCfg, logLevel slog.Level, configPath string, aux map[string]any, initState **state.State) (bool, error) {
 	ctx, cancel := context.WithCancelCause(context.Background())