add redis process, put circus in charge of process management

.gitignore

@@ -1,2 +1,2 @@
 result
-config.nix
+prod.config.nix

config.nix

@@ -1,9 +1,10 @@
 {
-    powSecret = "";
+    powSecret = "ssshhh";
     mlSMTPAddr = "";
     mlSMTPAuth = "";
-    dataDir = ".";
+    dataDir = "/tmp/mediocre-blog-data";
     publicURL = "http://localhost:4000";
     listenProto = "tcp";
     listenAddr = ":4000";
+    redisListenPath = "/tmp/mediocre-blog-redis";
 }

default.nix

@@ -3,11 +3,60 @@ let
     pkgs = utils.pkgs;
     system = utils.system;
 in
-    rec {
-        srv = (import ./srv).build;
-        static = (import ./static).build;
+    {config ? ./config.nix}: rec {
         config = (import ./config.nix);
 
+        static = (import ./static).build;
+
+        srv = (import ./srv).build;
+        srvBin = pkgs.writeScript "mediocregopher-mediocre-blog-srvBin" ''
+            #!/bin/sh
+            exec ${srv}/bin/mediocre-blog \
+                -pow-secret   "${config.powSecret}" \
+                -ml-smtp-addr "${config.mlSMTPAddr}" \
+                -ml-smtp-auth "${config.mlSMTPAuth}" \
+                -data-dir     "${config.dataDir}" \
+                -public-url   "${config.publicURL}" \
+                -static-dir   "${static}" \
+                -listen-proto "${config.listenProto}" \
+                -listen-addr  "${config.listenAddr}"
+        '';
+
+        redisCfg = pkgs.writeText "mediocregopher-mediocre-blog-redisCfg" ''
+            port 0
+            unixsocket ${config.redisListenPath}
+            daemonize no
+            loglevel notice
+            logfile ""
+            appendonly yes
+            appendfilename "appendonly.aof"
+            dir ${config.dataDir}/redis
+        '';
+
+        redisBin = pkgs.writeScript "mediocregopher-mediocre-blog-redisBin" ''
+            #!/bin/sh
+            mkdir -p ${config.dataDir}/redis
+            exec ${pkgs.redis}/bin/redis-server ${redisCfg}
+        '';
+
+        circusCfg = pkgs.writeText "mediocregopher-mediocre-blog-circusCfg" ''
+            [circus]
+            endpoint = tcp://127.0.0.1:0
+            pubsub_endpoint = tcp://127.0.0.1:0
+
+            [watcher:srv]
+            cmd = ${srvBin}
+            numprocesses = 1
+
+            [watcher:redis]
+            cmd = ${redisBin}
+            numprocesses = 1
+        '';
+
+        circusBin = pkgs.writeScript "mediocregopher-mediocre-blog-circusBin" ''
+            exec ${pkgs.circus}/bin/circusd ${circusCfg}
+        '';
+
         service = pkgs.writeText "mediocregopher-mediocre-blog" ''
             [Unit]
             Description=mediocregopher mediocre blog
@@ -18,15 +67,7 @@ in
             Restart=always
             RestartSec=1s
             User=mediocregopher
-            ExecStart=${srv}/bin/mediocre-blog \
-                -pow-secret   "${config.powSecret}" \
-                -ml-smtp-addr "${config.mlSMTPAddr}" \
-                -ml-smtp-auth "${config.mlSMTPAuth}" \
-                -data-dir     "${config.dataDir}" \
-                -public-url   "${config.publicURL}" \
-                -static-dir   "${static}" \
-                -listen-proto "${config.listenProto}" \
-                -listen-addr  "${config.listenAddr}"
+            ExecStart=${circusBin}
 
             [Install]
             WantedBy=multi-user.target

srv/cmd/mediocre-blog/main.go

@@ -62,10 +62,6 @@ func main() {
 		logger.Fatal(ctx, "-static-dir or -static-proxy-url is required")
 	case *powSecret == "":
 		logger.Fatal(ctx, "-pow-secret is required")
-	case *smtpAddr == "":
-		logger.Fatal(ctx, "-ml-smtp-addr is required")
-	case *smtpAuthStr == "":
-		logger.Fatal(ctx, "-ml-smtp-auth is required")
 	}
 
 	publicURL, err := url.Parse(*publicURLStr)
@@ -87,14 +83,22 @@ func main() {
 	}
 	powTarget := uint32(powTargetUint)
 
+	var mailerCfg mailinglist.MailerParams
+
+	if *smtpAddr != "" {
+		mailerCfg.SMTPAddr = *smtpAddr
 		smtpAuthParts := strings.SplitN(*smtpAuthStr, ":", 2)
 		if len(smtpAuthParts) < 2 {
 			logger.Fatal(ctx, "invalid -ml-smtp-auth")
 		}
-	smtpAuth := sasl.NewPlainClient("", smtpAuthParts[0], smtpAuthParts[1])
-	smtpSendAs := smtpAuthParts[0]
+		mailerCfg.SMTPAuth = sasl.NewPlainClient("", smtpAuthParts[0], smtpAuthParts[1])
+		mailerCfg.SendAs = smtpAuthParts[0]
 
-	// initialization
+		ctx = mctx.Annotate(ctx,
+			"smtpAddr", mailerCfg.SMTPAddr,
+			"smtpSendAs", mailerCfg.SendAs,
+		)
+	}
 
 	ctx = mctx.Annotate(ctx,
 		"publicURL", publicURL.String(),
@@ -102,10 +106,10 @@ func main() {
 		"listenAddr", *listenAddr,
 		"dataDir", *dataDir,
 		"powTarget", fmt.Sprintf("%x", powTarget),
-		"smtpAddr", *smtpAddr,
-		"smtpSendAs", smtpSendAs,
 	)
 
+	// initialization
+
 	if *staticDir != "" {
 		ctx = mctx.Annotate(ctx, "staticDir", *staticDir)
 	} else {
@@ -127,11 +131,13 @@ func main() {
 	// sugar
 	requirePow := func(h http.Handler) http.Handler { return requirePowMiddleware(powMgr, h) }
 
-	mailer := mailinglist.NewMailer(mailinglist.MailerParams{
-		SMTPAddr: *smtpAddr,
-		SMTPAuth: smtpAuth,
-		SendAs:   smtpSendAs,
-	})
+	var mailer mailinglist.Mailer
+	if *smtpAddr == "" {
+		logger.Info(ctx, "-smtp-addr not given, using NullMailer")
+		mailer = mailinglist.NullMailer
+	} else {
+		mailer = mailinglist.NewMailer(mailerCfg)
+	}
 
 	mlStore, err := mailinglist.NewStore(path.Join(*dataDir, "mailinglist.sqlite3"))
 	if err != nil {

srv/mailinglist/mailer.go

@@ -10,6 +10,15 @@ type Mailer interface {
 	Send(to, subject, body string) error
 }
 
+// NullMailer acts as a Mailer but actually just does nothing.
+var NullMailer = nullMailer{}
+
+type nullMailer struct{}
+
+func (nullMailer) Send(to, subject, body string) error {
+	return nil
+}
+
 // MailerParams are used to initialize a new Mailer instance
 type MailerParams struct {
 	SMTPAddr string