cache and db now use time.Ticker for events. refactored some initialization.

5 files changed, 170 insertions, 108 deletions

diff --git a/svc/cache.go b/svc/cache.go
index 20c3953..3383016 100644
--- a/svc/cache.go
+++ b/svc/cache.go
@@ -9,6 +9,13 @@ import (
 	"time"
 )
 
+// These functions and types pertain to the
+// in-memory data being used by the registry
+// service, such as:
+//  - static assets (index.html, style.css)
+//  - the registry itself (users, etc)
+//  - list of other registries submitted
+
 // RemoteRegistries holds a list of remote registries to
 // periodically scrape for new users. The remote registries
 // must have been added via POST like a user.
@@ -17,6 +24,10 @@ type RemoteRegistries struct {
 	List []string
 }
 
+// staticAssets holda the rendered landing page
+// as a byte slice, its on-disk mod time, the
+// assets/style.css file as a byte slice, and
+// its on-disk mod time.
 type staticAssets struct {
 	mu       sync.RWMutex
 	index    []byte
@@ -25,6 +36,9 @@ type staticAssets struct {
 	cssMod   time.Time
 }
 
+// Renders the landing page template using
+// the info supplied in the configuration
+// file's "Instance" section.
 func initTemplates() *template.Template {
 	confObj.Mu.RLock()
 	assetsDir := confObj.AssetsDir
@@ -33,30 +47,7 @@ func initTemplates() *template.Template {
 	return template.Must(template.ParseFiles(assetsDir + "/tmpl/index.html"))
 }
 
-func cacheTimer() bool {
-	confObj.Mu.RLock()
-	answer := time.Since(confObj.LastCache) > confObj.CacheInterval
-	confObj.Mu.RUnlock()
-
-	return answer
-}
-
-// Launched by init as a coroutine to watch
-// for the update intervals to pass.
-func cacheAndPush() {
-	for {
-		if cacheTimer() {
-			refreshCache()
-		}
-		if dbTimer() {
-			errLog("Error pushing cache to database: ", pushDB())
-		}
-		time.Sleep(1000 * time.Millisecond)
-	}
-}
-
-func refreshCache() {
-
+func cacheUpdate() {
 	// This clusterfuck of mutex read locks is
 	// necessary to avoid deadlock. This mess
 	// also avoids a panic that would occur
@@ -84,7 +75,6 @@ func refreshCache() {
 // need to be re-cached. If they do, they are
 // pulled back into memory from disk.
 func pingAssets() {
-
 	confObj.Mu.RLock()
 	assetsDir := confObj.AssetsDir
 	confObj.Mu.RUnlock()
diff --git a/svc/cache_test.go b/svc/cache_test.go
index 29b92b8..28e5c0b 100644
--- a/svc/cache_test.go
+++ b/svc/cache_test.go
@@ -2,76 +2,32 @@ package svc // import "github.com/getwtxt/getwtxt/svc"
 
 import (
 	"testing"
-	"time"
 )
 
-func Test_cacheTimer(t *testing.T) {
-	initTestConf()
-	dur, _ := time.ParseDuration("5m")
-	back30, _ := time.ParseDuration("-30m")
-
-	cases := []struct {
-		name      string
-		lastCache time.Time
-		interval  time.Duration
-		expect    bool
-	}{
-		{
-			name:      "Past Interval",
-			lastCache: time.Now().Add(back30),
-			interval:  dur,
-			expect:    true,
-		},
-		{
-			name:      "Before Interval",
-			lastCache: time.Now(),
-			interval:  dur,
-			expect:    false,
-		},
-	}
-
-	for _, tt := range cases {
-		t.Run(tt.name, func(t *testing.T) {
-
-			confObj.Mu.Lock()
-			confObj.LastCache = tt.lastCache
-			confObj.CacheInterval = tt.interval
-			confObj.Mu.Unlock()
-
-			res := cacheTimer()
-
-			if res != tt.expect {
-				t.Errorf("Got %v, expected %v\n", res, tt.expect)
-			}
-		})
-	}
-
-}
-
-func Test_refreshCache(t *testing.T) {
+func Test_cacheUpdate(t *testing.T) {
 	initTestConf()
 	confObj.Mu.RLock()
 	prevtime := confObj.LastCache
 	confObj.Mu.RUnlock()
 
 	t.Run("Cache Time Check", func(t *testing.T) {
-		refreshCache()
+		cacheUpdate()
 		confObj.Mu.RLock()
 		newtime := confObj.LastCache
 		confObj.Mu.RUnlock()
 
 		if !newtime.After(prevtime) || newtime == prevtime {
-			t.Errorf("Cache time did not update, check refreshCache() logic\n")
+			t.Errorf("Cache time did not update, check cacheUpdate() logic\n")
 		}
 	})
 }
 
-func Benchmark_refreshCache(b *testing.B) {
+func Benchmark_cacheUpdate(b *testing.B) {
 	initTestConf()
 	b.ResetTimer()
 
 	for i := 0; i < b.N; i++ {
-		refreshCache()
+		cacheUpdate()
 	}
 }
 
diff --git a/svc/conf.go b/svc/conf.go
index 0d9e739..ccd819c 100644
--- a/svc/conf.go
+++ b/svc/conf.go
@@ -12,7 +12,8 @@ import (
 	"github.com/spf13/viper"
 )
 
-// Configuration object definition
+// Configuration values are held in an instance of
+// this struct.
 type Configuration struct {
 	Mu            sync.RWMutex
 	Port          int           `yaml:"ListenPort"`
@@ -28,7 +29,8 @@ type Configuration struct {
 	Instance      `yaml:"Instance"`
 }
 
-// Instance refers to this specific instance of getwtxt
+// Instance refers to meta data about
+// this specific instance of getwtxt
 type Instance struct {
 	Vers  string `yaml:"-"`
 	Name  string `yaml:"Instance.SiteName"`
@@ -38,29 +40,104 @@ type Instance struct {
 	Desc  string `yaml:"Instance.Description"`
 }
 
+// This is a wrapper for a *time.Ticker
+// that adds another channel. It's used
+// to signal to the ticker goroutines
+// that they should stop the tickers
+// and exit.
+type tick struct {
+	isDB bool
+	t    *time.Ticker
+	exit chan bool
+}
+
+// Creates a new instance of a tick
+func initTicker(db bool, interval time.Duration) *tick {
+	return &tick{
+		isDB: db,
+		t:    time.NewTicker(interval),
+		exit: make(chan bool, 1),
+	}
+}
+
+// Sends the signal to stop the tickers
+// and for their respective goroutines
+// to exit.
+func killTickers() {
+	ct := <-cTickC
+	dt := <-dbTickC
+	ct.exit <- true
+	dt.exit <- true
+}
+
+// Waits for a signal from the database
+// *tick. Either stops the ticker and
+// kills the goroutine or it will
+// update cache / push the DB to disk
+func dataTimer(tkr *tick) {
+	for {
+		select {
+		case signal := <-tkr.t.C:
+			if tkr.isDB {
+				errLog("", pushDB())
+				log.Printf("Database push took: %v\n", time.Since(signal))
+				continue
+			}
+			cacheUpdate()
+			log.Printf("Cache update took: %v\n", time.Since(signal))
+		case <-tkr.exit:
+			tkr.t.Stop()
+			return
+		}
+	}
+}
+
+// Called on start-up. Initializes everything
+// related to configuration values.
 func initConfig() {
+	log.Printf("Loading configuration ...\n")
 
 	parseConfigFlag()
-
 	setConfigDefaults()
 
-	log.Printf("Loading configuration ...\n")
 	if err := viper.ReadInConfig(); err != nil {
 		log.Printf("%v\n", err.Error())
 		log.Printf("Using defaults ...\n")
 		bindConfig()
 		return
 	}
-
 	viper.WatchConfig()
-	viper.OnConfigChange(func(e fsnotify.Event) {
-		log.Printf("Config file change detected. Reloading...\n")
-		bindConfig()
-		initLogging()
-	})
+	viper.OnConfigChange(reInit)
+
+	bindConfig()
+}
+
+// Called when a change is detected in the
+// configuration file. Closes log file,
+// closes database connection, stops all
+// tickers, then binds new configuration
+// values, opens new log file, connects to
+// new database, and starts new cache and
+// database tickers.
+func reInit(e fsnotify.Event) {
+	log.Printf("%v. Reloading...\n", e.String())
+
+	if !confObj.StdoutLogging {
+		closeLog <- true
+	}
+
+	killTickers()
+	killDB()
+
 	bindConfig()
+
+	initLogging()
+	initDatabase()
+	initPersistence()
 }
 
+// Registers either stdout or a specified file
+// to the default logger.
 func initLogging() {
 
 	confObj.Mu.RLock()
@@ -92,6 +169,8 @@ func initLogging() {
 	confObj.Mu.RUnlock()
 }
 
+// Default values should a config file
+// not be available.
 func setConfigDefaults() {
 	viper.SetDefault("ListenPort", 9001)
 	viper.SetDefault("LogFile", "getwtxt.log")
@@ -109,6 +188,8 @@ func setConfigDefaults() {
 	viper.SetDefault("Instance.Description", "A fast, resilient twtxt registry server written in Go!")
 }
 
+// Reads data from the configuration
+// flag and acts accordingly.
 func parseConfigFlag() {
 	if *flagConfFile == "" {
 		viper.SetConfigName("getwtxt")
@@ -130,6 +211,9 @@ func parseConfigFlag() {
 	}
 }
 
+// Simply goes down the list of fields
+// in the confObj instance of &Configuration{},
+// assigning values from the config file.
 func bindConfig() {
 	confObj.Mu.Lock()
 
diff --git a/svc/db.go b/svc/db.go
index 3841d83..260c5cc 100644
--- a/svc/db.go
+++ b/svc/db.go
@@ -1,18 +1,26 @@
 package svc // import "github.com/getwtxt/getwtxt/svc"
 
 import (
-	"time"
-
 	"github.com/syndtr/goleveldb/leveldb"
 	"golang.org/x/sys/unix"
 )
 
+// Everything in this file is database-agnostic.
+// Functions and types related to specific kinds
+// of databases will be in their own respective
+// files, such as:
+//  - leveldb.go
+//  - sqlite.go
+
+// Abstraction to allow several different
+// databases to be used interchangeably.
 type dbase interface {
 	push() error
 	pull()
 }
 
-// Pull DB data into cache, if available.
+// Opens a new connection to the specified
+// database, then reads it into memory.
 func initDatabase() {
 	var db dbase
 	confObj.Mu.RLock()
@@ -35,16 +43,19 @@ func initDatabase() {
 	pullDB()
 }
 
-func dbTimer() bool {
-	confObj.Mu.RLock()
-	answer := time.Since(confObj.LastPush) > confObj.DBInterval
-	confObj.Mu.RUnlock()
-
-	return answer
+// Close the database connection.
+func killDB() {
+	db := <-dbChan
+	switch dbType := db.(type) {
+	case *dbLevel:
+		errLog("", dbType.db.Close())
+	case *dbSqlite:
+		errLog("", dbType.db.Close())
+	}
 }
 
-// Pushes the registry's cache data to a local
-// database for safe keeping.
+// Pushes the registry's cache data
+// to a local database for safe keeping.
 func pushDB() error {
 	db := <-dbChan
 	err := db.push()
@@ -55,6 +66,7 @@ func pushDB() error {
 	return err
 }
 
+// Reads the database from disk into memory.
 func pullDB() {
 	db := <-dbChan
 	db.pull()
diff --git a/svc/init.go b/svc/init.go
index e63ffdd..71527cf 100644
--- a/svc/init.go
+++ b/svc/init.go
@@ -24,24 +24,32 @@ var (
 	flagDBType   *string = pflag.StringP("dbtype", "t", "", "Type of database being used")
 )
 
+// Holds the global configuration
 var confObj = &Configuration{}
 
-// signals to close the log file
+// Signals to close the log file
 var closeLog = make(chan bool, 1)
 
-// used to transmit database pointer after
-// initialization
+// Used to transmit database pointer, database ticker,
+// and cache ticker after initialization
 var dbChan = make(chan dbase, 1)
+var dbTickC = make(chan *tick, 1)
+var cTickC = make(chan *tick, 1)
 
+// Used to manage the landing page template
 var tmpls *template.Template
 
+// Holds the registry data in-memory
 var twtxtCache = registry.NewIndex()
 
+// List of other registries submitted to this registry
 var remoteRegistries = &RemoteRegistries{
 	Mu:   sync.RWMutex{},
 	List: make([]string, 0),
 }
 
+// In-memory cache of static assets, specifically
+// the parsed landing page and the stylesheet.
 var staticCache = &staticAssets{}
 
 func errFatal(context string, err error) {
@@ -62,13 +70,15 @@ func errLog(context string, err error) {
 func initSvc() {
 	checkFlags()
 	titleScreen()
+
 	initConfig()
 	initLogging()
 	initDatabase()
-	go cacheAndPush()
 	tmpls = initTemplates()
-	watchForInterrupt()
+	initPersistence()
+
 	pingAssets()
+	watchForInterrupt()
 }
 
 func checkFlags() {
@@ -90,6 +100,22 @@ func checkFlags() {
 	}
 }
 
+// Starts the tickers that periodically:
+//  - pull new user statuses into cache
+//  - push cached data to disk
+func initPersistence() {
+	confObj.Mu.RLock()
+	cacheTkr := initTicker(false, confObj.CacheInterval)
+	dbTkr := initTicker(true, confObj.DBInterval)
+	confObj.Mu.RUnlock()
+
+	go dataTimer(cacheTkr)
+	go dataTimer(dbTkr)
+
+	dbTickC <- dbTkr
+	cTickC <- cacheTkr
+}
+
 // Watch for SIGINT aka ^C
 // Close the log file then exit
 func watchForInterrupt() {
@@ -103,14 +129,8 @@ func watchForInterrupt() {
 			confObj.Mu.RLock()
 			log.Printf("Closing database connection to %v...\n", confObj.DBPath)
 
-			db := <-dbChan
-
-			switch dbType := db.(type) {
-			case *dbLevel:
-				errLog("", dbType.db.Close())
-			case *dbSqlite:
-				errLog("", dbType.db.Close())
-			}
+			killTickers()
+			killDB()
 
 			if !confObj.StdoutLogging {
 				closeLog <- true