From 11ddf35e811080a53c57b50cfe495b1b6e9879cd Mon Sep 17 00:00:00 2001
From: Ian Gulliver <github@flamingcow.io>
Date: Sat, 17 Jun 2023 15:05:42 -0700
Subject: [PATCH] Integrate event into candidate

---
 candidate.go | 46 +++++++++++++++++++++++++++++-----------------
 lib_test.go  |  6 +++---
 2 files changed, 32 insertions(+), 20 deletions(-)

diff --git a/candidate.go b/candidate.go
index 4907e3b..cda1526 100644
--- a/candidate.go
+++ b/candidate.go
@@ -1,23 +1,26 @@
 package elect
 
 import (
+	"context"
 	"crypto/hmac"
 	"encoding/json"
 	"flag"
 	"fmt"
 	"io"
-	"log"
 	"net/http"
 	"sync"
 	"time"
 
 	"github.com/dchest/uniuri"
+	"github.com/gopatchy/event"
 	"github.com/samber/lo"
 )
 
 type Candidate struct {
 	C <-chan CandidateState
 
+	ec *event.Client
+
 	numVoters  int
 	signingKey []byte
 	stop       chan bool
@@ -53,11 +56,12 @@ var StateName = map[CandidateState]string{
 
 var electForceState = flag.String("elect-force-state", "", "'', 'leader', 'notleader'")
 
-func NewCandidate(numVoters int, signingKey string) *Candidate {
+func NewCandidate(ctx context.Context, ec *event.Client, numVoters int, signingKey string) *Candidate {
 	change := make(chan CandidateState, 100)
 
 	c := &Candidate{
 		C:          change,
+		ec:         ec,
 		numVoters:  numVoters,
 		signingKey: []byte(signingKey),
 		votes:      map[string]*vote{},
@@ -72,11 +76,15 @@ func NewCandidate(numVoters int, signingKey string) *Candidate {
 	}
 
 	if c.forceState != StateUndefined {
-		c.log("state forced to %s", StateName[c.forceState])
+		c.log(ctx, ec,
+			"event", "state forced",
+			"newState", StateName[c.forceState],
+		)
+
 		c.state = c.forceState
 	}
 
-	go c.loop()
+	go c.loop(ctx, ec)
 
 	return c
 }
@@ -189,10 +197,10 @@ func (c *Candidate) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	c.elect(v)
+	c.elect(r.Context(), c.ec, v)
 }
 
-func (c *Candidate) elect(v *vote) {
+func (c *Candidate) elect(ctx context.Context, ec *event.Client, v *vote) {
 	c.mu.Lock()
 	defer c.mu.Unlock()
 
@@ -205,13 +213,14 @@ func (c *Candidate) elect(v *vote) {
 			return
 		}
 
-		c.log(
-			"transitioning %s -> %s (no=%d yes=%d max_no=0 min_yes=%d)",
-			StateName[c.state],
-			StateName[state],
-			no,
-			yes,
-			c.numVoters/2+1,
+		c.log(ctx, ec,
+			"event", "transitioning state",
+			"oldState", StateName[c.state],
+			"newState", StateName[state],
+			"noVotes", no,
+			"yesVotes", yes,
+			"maxNo", 0,
+			"minYes", c.numVoters/2+1,
 		)
 
 		c.state = state
@@ -275,7 +284,7 @@ func (c *Candidate) elect(v *vote) {
 	state = StateLeader
 }
 
-func (c *Candidate) loop() {
+func (c *Candidate) loop(ctx context.Context, ec *event.Client) {
 	t := time.NewTicker(1 * time.Second)
 	defer t.Stop()
 	defer close(c.done)
@@ -286,13 +295,16 @@ func (c *Candidate) loop() {
 			return
 
 		case <-t.C:
-			c.elect(nil)
+			c.elect(ctx, ec, nil)
 		}
 	}
 }
 
-func (c *Candidate) log(format string, args ...any) {
-	log.Printf("[candidate] "+format, args...)
+func (c *Candidate) log(ctx context.Context, ec *event.Client, vals ...any) {
+	ec.Log(ctx, append([]any{
+		"library", "elect",
+		"subsystem", "candidate",
+	}, vals...)...)
 }
 
 func getForceState() CandidateState {
diff --git a/lib_test.go b/lib_test.go
index cf63e2c..ae33dc7 100644
--- a/lib_test.go
+++ b/lib_test.go
@@ -33,9 +33,9 @@ type Waiter struct {
 	chans []<-chan bool
 }
 
-func NewTestServer(t *testing.T, numVoters int, signingKey string) *TestServer {
+func NewTestServer(ctx context.Context, t *testing.T, ec *event.Client, numVoters int, signingKey string) *TestServer {
 	ts := &TestServer{
-		Candidate: elect.NewCandidate(numVoters, signingKey),
+		Candidate: elect.NewCandidate(ctx, ec, numVoters, signingKey),
 		listener:  lo.Must(net.ListenTCP("tcp", nil)),
 	}
 
@@ -72,7 +72,7 @@ func NewTestSystem(t *testing.T, numCandidates, numVoters int) *TestSystem {
 	}
 
 	for i := 0; i < numCandidates; i++ {
-		ts.servers = append(ts.servers, NewTestServer(t, numVoters, ts.signingKey))
+		ts.servers = append(ts.servers, NewTestServer(ctx, t, ec, numVoters, ts.signingKey))
 	}
 
 	for i := 0; i < numVoters; i++ {