add notifier package

7 files changed, 102 insertions, 68 deletions

diff --git a/README.md b/README.md
index eda378c..05bccc9 100644
--- a/README.md
+++ b/README.md
@@ -7,6 +7,6 @@ This project is still under development!
 ## TODO
 
 * Finish this TODO
-* Add `notify.go` from Gogios, to notify on state changes.
+* Use this to control remote Gorum check execution
 * Release Gorum
 * Write a blog post
diff --git a/cmd/gorum/main.go b/cmd/gorum/main.go
index 80827e9..9cb74c7 100644
--- a/cmd/gorum/main.go
+++ b/cmd/gorum/main.go
@@ -11,7 +11,7 @@ import (
 	"codeberg.org/snonux/gorum/internal"
 )
 
-const versionStr = "v0.0.3"
+const versionStr = "v0.0.4"
 
 func main() {
 	configFile := flag.String("cfg", "/etc/gorum.json", "The config file")
diff --git a/internal/config/config.go b/internal/config/config.go
index 3968268..2753ac9 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -35,6 +35,7 @@ type Config struct {
 	EmailTo       string `json:"EmailTo,omitempty"`
 	EmailFrom     string `json:"EmailFrom,omitempty"`
 	SMTPServer    string `json:"SMTPServer,omitempty"`
+	MailThrottle  int    `json:"MailThrottle,omitempty"`
 }
 
 func NewFromConfigFile(configFile string) (Config, error) {
@@ -69,6 +70,21 @@ func NewFromConfigFile(configFile string) (Config, error) {
 	}
 	conf.Nodes = newNodes
 
+	if conf.SMTPServer == "" {
+		hostname, err := os.Hostname()
+		if err != nil {
+			log.Fatal(err)
+		}
+		conf.SMTPServer = fmt.Sprintf("%s:25", hostname)
+		log.Println("Set SMTPServer to " + conf.SMTPServer)
+	}
+
+	if conf.MailThrottle == 0 {
+		// By default, send out an E-Mail once every minute max. This
+		// is to avoid E-Mail bursts.
+		conf.MailThrottle = 60
+	}
+
 	return conf.setDefaults()
 }
 
@@ -188,3 +204,7 @@ func (conf Config) findNode(hostname string) (Node, error) {
 
 	return Node{}, fmt.Errorf("node %s not found in %v", hostname, conf.Nodes)
 }
+
+func (conf Config) EmailNotifycationEnabled() bool {
+	return conf.EmailFrom != "" && conf.EmailTo != "" && conf.SMTPServer != ""
+}
diff --git a/internal/quorum/notify.go b/internal/notifier/email.go
index 7761b4d..4ce8d69 100644
--- a/internal/quorum/notify.go
+++ b/internal/notifier/email.go
@@ -1,4 +1,4 @@
-package quorum
+package notifier
 
 import (
 	"fmt"
@@ -8,15 +8,10 @@ import (
 	"codeberg.org/snonux/gorum/internal/config"
 )
 
-func notifyEnabled(conf config.Config) bool {
-	return conf.EmailFrom != "" && conf.EmailTo != "" && conf.SMTPServer != ""
-}
-
-func notify(conf config.Config, subject, body string) error {
-	if !notifyEnabled(conf) {
+func emailNotify(conf config.Config, subject, body string) error {
+	if !conf.EmailNotifycationEnabled() {
 		return nil
 	}
-
 	log.Println("notify:", subject, body)
 
 	headers := map[string]string{
@@ -39,10 +34,8 @@ func notify(conf config.Config, subject, body string) error {
 		[]string{conf.EmailTo}, []byte(message))
 }
 
-func notifyError(conf config.Config, err error) {
-	if notifyEnabled(conf) {
-		if err := notify(conf, fmt.Sprintf("GORUM: An error occured: %v", err), err.Error()); err != nil {
-			log.Println("error:", err)
-		}
+func emailNotifyError(conf config.Config, err error) {
+	if err := emailNotify(conf, fmt.Sprintf("GORUM: An error occured: %v", err), err.Error()); err != nil {
+		log.Println("error:", err)
 	}
 }
diff --git a/internal/notifier/notifier.go b/internal/notifier/notifier.go
new file mode 100644
index 0000000..24447a9
--- /dev/null
+++ b/internal/notifier/notifier.go
@@ -0,0 +1,60 @@
+package notifier
+
+import (
+	"context"
+	"fmt"
+	"os"
+
+	"codeberg.org/snonux/gorum/internal/config"
+)
+
+type Notifier struct{}
+
+func New() Notifier {
+	return Notifier{}
+}
+
+func (notifier Notifier) Start(ctx context.Context, conf config.Config, scoreCh <-chan string) {
+	go func() {
+		for scoresStr := range scoreCh {
+			if err := notifier.persist(conf, scoresStr); err != nil {
+				emailNotifyError(conf, err)
+			}
+		}
+	}()
+}
+
+func (notifier Notifier) persist(conf config.Config, scoresStr string) error {
+	if err := emailNotify(conf, "GORUM: Quorum changed", scoresStr); err != nil {
+		return err
+	}
+
+	if _, err := os.Stat(conf.StateDir); os.IsNotExist(err) {
+		if err := os.MkdirAll(conf.StateDir, 0755); err != nil {
+			return err
+		}
+	}
+
+	return writeFileViaTmp(fmt.Sprintf("%s/%s", conf.StateDir, conf.ScoreFile), scoresStr)
+}
+
+// Create tmp file first, and then, once written, rename it.
+func writeFileViaTmp(filePath, content string) error {
+	tmpFilePath := fmt.Sprintf("%s.tmp", filePath)
+
+	fd, err := os.Create(tmpFilePath)
+	if err != nil {
+		return err
+	}
+	defer fd.Close()
+
+	if _, err := fd.WriteString(content); err != nil {
+		return err
+	}
+
+	if err := fd.Sync(); err != nil {
+		return err
+	}
+
+	return os.Rename(tmpFilePath, filePath)
+}
diff --git a/internal/quorum/quorum.go b/internal/quorum/quorum.go
index 71954f4..d730fed 100644
--- a/internal/quorum/quorum.go
+++ b/internal/quorum/quorum.go
@@ -2,9 +2,7 @@ package quorum
 
 import (
 	"context"
-	"fmt"
 	"log"
-	"os"
 	"sort"
 	"strconv"
 	"strings"
@@ -32,8 +30,9 @@ func New(conf config.Config) Quorum {
 	}
 }
 
-func (quo Quorum) Start(ctx context.Context) <-chan vote.Vote {
-	ch := make(chan vote.Vote)
+func (quo Quorum) Start(ctx context.Context) (<-chan vote.Vote, <-chan string) {
+	voteCh := make(chan vote.Vote)
+	scoreCh := make(chan string)
 
 	interval := time.Second * time.Duration(quo.conf.LoopIntervalS)
 	if vote.Expiry <= interval {
@@ -42,7 +41,8 @@ func (quo Quorum) Start(ctx context.Context) <-chan vote.Vote {
 	}
 
 	go func() {
-		defer close(ch)
+		defer close(voteCh)
+		defer close(scoreCh)
 
 		var (
 			myVote  vote.Vote
@@ -54,25 +54,21 @@ func (quo Quorum) Start(ctx context.Context) <-chan vote.Vote {
 			case <-time.After(interval):
 				myVote, _ = quo.makeMyVote()
 				log.Println("quorum: made my vote:", myVote)
-				ch <- myVote
+				voteCh <- myVote
 			case v := <-quo.voteCh:
 				quo.vote(v)
 				if myVote, changed = quo.makeMyVote(); changed {
 					log.Println("quorum: changed my vote:", myVote)
-					ch <- myVote
+					voteCh <- myVote
+					scoreCh <- quo.strs()
 				}
 			case <-ctx.Done():
 				return
 			}
-
-			if err := quo.persist(changed); err != nil {
-				log.Println("quorum:", err)
-				notifyError(quo.conf, err)
-			}
 		}
 	}()
 
-	return ch
+	return voteCh, scoreCh
 }
 
 func (quo Quorum) Vote(v vote.Vote) {
@@ -149,24 +145,6 @@ func (quo *Quorum) strs() string {
 	return sb.String()
 }
 
-func (quo *Quorum) persist(changed bool) error {
-	scoresStr := quo.strs()
-
-	if changed {
-		if err := notify(quo.conf, "GORUM: Quorum changed", scoresStr); err != nil {
-			return err
-		}
-	}
-
-	if _, err := os.Stat(quo.conf.StateDir); os.IsNotExist(err) {
-		if err := os.MkdirAll(quo.conf.StateDir, 0755); err != nil {
-			return err
-		}
-	}
-
-	return writeFileViaTmp(fmt.Sprintf("%s/%s", quo.conf.StateDir, quo.conf.ScoreFile), scoresStr)
-}
-
 func (quo *Quorum) makeMyVote() (vote.Vote, bool) {
 	newVote, err := quo.expireOldVotes()
 	if err != nil {
@@ -201,24 +179,3 @@ func (quo Quorum) expireOldVotes() (vote.Vote, error) {
 
 	return vote.New(quo.conf, live...)
 }
-
-// Create tmp file first, and then, once written, rename it.
-func writeFileViaTmp(filePath, content string) error {
-	tmpFilePath := fmt.Sprintf("%s.tmp", filePath)
-
-	fd, err := os.Create(tmpFilePath)
-	if err != nil {
-		return err
-	}
-	defer fd.Close()
-
-	if _, err := fd.WriteString(content); err != nil {
-		return err
-	}
-
-	if err := fd.Sync(); err != nil {
-		return err
-	}
-
-	return os.Rename(tmpFilePath, filePath)
-}
diff --git a/internal/run.go b/internal/run.go
index 2439928..d07ba28 100644
--- a/internal/run.go
+++ b/internal/run.go
@@ -7,6 +7,7 @@ import (
 
 	"codeberg.org/snonux/gorum/internal/client"
 	"codeberg.org/snonux/gorum/internal/config"
+	"codeberg.org/snonux/gorum/internal/notifier"
 	"codeberg.org/snonux/gorum/internal/quorum"
 	"codeberg.org/snonux/gorum/internal/server"
 )
@@ -32,9 +33,12 @@ func Run(ctx context.Context, configFile string, loopIntervalS int64) error {
 	log.Println("Starting everything up!")
 
 	quo := quorum.New(conf)
-	myVoteCh := quo.Start(ctx)
+	notifier := notifier.New()
+
+	myVoteCh, scoreCh := quo.Start(ctx)
 	server.Start(ctx, conf, quo)
 	client.Start(ctx, conf, myVoteCh)
+	notifier.Start(ctx, conf, scoreCh)
 
 	<-ctx.Done()
 	log.Println("Good bye and have a nice day!")