Fix misrouted notifications from SQLite lock contention

send_message silently fell back to the default conversation whenever the
plan-time or slack-channel lookup errored, because the query error was
ignored. A transient "database is locked" (from the channel-creation/sync
routine holding the write lock while making slow Slack API calls) thus
misrouted a service notification to the admin DM instead of the event
channel.

- api.go: capture lookup errors and only treat gorm.ErrRecordNotFound as
  "no service / no channel"; on any other error, fail so the caller retries
  rather than posting to the wrong conversation.
- database.go: open SQLite with WAL journaling and a 10s busy timeout so
  reads proceed alongside the sync writer instead of locking.
- Bump version to 0.2.2.

README.md

@@ -125,7 +125,7 @@ slack:
     api_token: SLACK_API_TOKEN
     create_from_weekday: 3
     default_conversation: SLACK_UID
-	sticky_users:
+    sticky_users:
         - SLACK_UID
 
 ```

api.go

@@ -2,12 +2,14 @@ package main
 
 import (
 	"encoding/json"
+	"errors"
 	"log"
 	"net/http"
 	"time"
 
 	"github.com/gorilla/mux"
 	"github.com/slack-go/slack"
+	"gorm.io/gorm"
 )
 
 // Commonly used strings.
@@ -98,13 +100,34 @@ func (s *HTTPServer) RegisterAPIRoutes(r *mux.Router) {
 		now := time.Now().UTC()
 		conversation := app.config.Slack.DefaultConversation
 
-		// Find plan times that are occuring right now.
+		// Find plan times that are occuring right now. A 60-minute buffer
+		// is applied past ends_at so services that run long still resolve
+		// to their event channel instead of falling back to the default.
+		// Order by starts_at DESC so the most recent active service wins
+		// when a later service's window overlaps an earlier service's buffer.
 		var planTime PlanTimes
-		app.db.Where("time_type='service' AND starts_at < ? AND ends_at > ?", now, now).First(&planTime)
+		err = app.db.Where("time_type='service' AND starts_at < ? AND ends_at > ?", now, now.Add(-60*time.Minute)).Order("starts_at DESC").First(&planTime).Error
+		// A "record not found" simply means no service is occuring right now, in
+		// which case we fall back to the default conversation. Any other error
+		// (e.g. "database is locked") must NOT be swallowed: treating it as "no
+		// service" would silently misroute the message to the default
+		// conversation instead of the event channel. Fail so the caller retries.
+		if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
+			log.Println("Error looking up plan time:", err)
+			s.APISendGeneralResp(w, APIERR, "Error looking up plan time")
+			return
+		}
 		if planTime.Plan != 0 {
 			// If plan found, check for the slack channel.
 			var channel SlackChannels
-			app.db.Where("pc_plan = ?", planTime.Plan).First(&channel)
+			err = app.db.Where("pc_plan = ?", planTime.Plan).First(&channel).Error
+			// As above, only "record not found" is a benign result here. On any
+			// other error we must not fall through to the default conversation.
+			if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
+				log.Println("Error looking up slack channel:", err)
+				s.APISendGeneralResp(w, APIERR, "Error looking up slack channel")
+				return
+			}
 			if channel.ID != "" {
 				// If slack channel found, update the conversation to the channel ID.
 				conversation = channel.ID

database.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"log"
+	"strings"
 	"time"
 
 	"gorm.io/driver/mysql"
@@ -126,7 +127,21 @@ func (a *App) InitDB() {
 	}
 	// Depending on connection configuration, open the database.
 	if a.config.DB.Type == "sqlite3" {
-		a.db, err = gorm.Open(sqlite.Open(a.config.DB.Connection), dbConfig)
+		// Enable WAL journaling and a busy timeout. Without WAL, a single
+		// long-running writer (e.g. the channel-creation/sync routine, which
+		// interleaves slow Slack API calls with its writes) blocks all readers,
+		// causing "database is locked" on concurrent reads such as the
+		// send_message channel lookup. WAL lets reads proceed alongside the
+		// writer, and the busy timeout makes any remaining contention wait
+		// rather than fail immediately. Append as DSN pragmas, preserving any
+		// query string already present in the configured connection.
+		conn := a.config.DB.Connection
+		sep := "?"
+		if strings.Contains(conn, "?") {
+			sep = "&"
+		}
+		conn += sep + "_journal_mode=WAL&_busy_timeout=10000"
+		a.db, err = gorm.Open(sqlite.Open(conn), dbConfig)
 	} else if a.config.DB.Type == "mysql" {
 		a.db, err = gorm.Open(mysql.Open(a.config.DB.Connection), dbConfig)
 	} else if a.config.DB.Type == "postgres" {

main.go

@@ -13,7 +13,7 @@ import (
 const (
 	serviceName        = "service-notifications"
 	serviceDescription = "Notifications for church services"
-	serviceVersion     = "0.2"
+	serviceVersion     = "0.2.2"
 )
 
 // App is the global application structure for communicating between servers and storing information.

update.go

@@ -110,7 +110,8 @@ func UpdatePCData() {
 		// Get the plans for this service type.
 		allPlans, err := PCGetAll(fmt.Sprintf("/services/v2/service_types/%d/plans", serviceTypeID))
 		if err != nil {
-			log.Fatalln(err)
+			log.Println("Error getting plans for service type:", serviceTypeID, err)
+			continue
 		}
 		// For each plan, update data in database and pull other plan releated items for updates.
 		for _, data := range allPlans {
@@ -152,7 +153,8 @@ func UpdatePCData() {
 			// Get all times for this plan.
 			allPlanTimes, err := PCGetAll(fmt.Sprintf("/services/v2/service_types/%d/plans/%d/plan_times", serviceTypeID, planID))
 			if err != nil {
-				log.Fatalln(err)
+				log.Println("Error getting plan times for plan:", planID, err)
+				continue
 			}
 			// With each time, save it to the database.
 			for _, data := range allPlanTimes {
@@ -188,7 +190,8 @@ func UpdatePCData() {
 			// Get all members of the plan.
 			allTeamMembers, err := PCGetAll(fmt.Sprintf("/services/v2/service_types/%d/plans/%d/team_members", serviceTypeID, planID))
 			if err != nil {
-				log.Fatalln(err)
+				log.Println("Error getting team members for plan:", planID, err)
+				continue
 			}
 			// With each member, update the database.
 			for _, data := range allTeamMembers {
@@ -226,11 +229,13 @@ func UpdateSlackData() {
 	// Get all users from Slack.
 	users, err := app.slack.GetUsers()
 	if err != nil {
-		log.Fatalln(err)
+		log.Println("Error getting Slack users:", err)
+		return
 	}
 	// If no users returned, error as we should have some...
 	if len(users) == 0 {
-		log.Fatalln("No users found in Slack.")
+		log.Println("No users found in Slack.")
+		return
 	}
 	// With each user, update the database.
 	for _, user := range users {
@@ -354,7 +359,8 @@ func CreateSlackChannels() {
 	app.db.Where("time_type='service' AND starts_at > ? AND starts_at < ?", startDate, lastDate).Find(&planTimes)
 	// If no plan times matched, exit here.
 	if len(planTimes) == 0 {
-		log.Fatalln("No services found for this time frame.")
+		log.Println("No services found for this time frame.")
+		return
 	}
 
 	// With each plan time found, create a slack channel.
@@ -432,22 +438,28 @@ func CreateSlackChannels() {
 			log.Println("Creating channel:", channel.Name)
 			schan, err := app.slack.CreateConversation(channelInfo)
 			if err != nil {
-				log.Fatalln("Failed to create channel:", err)
+				log.Println("Failed to create channel:", err)
+				continue
 			}
 
 			// If topic is defined, set the topic and purpose.
 			if topic != "" {
-				// Sleep before, as it takes time for Slack APIs
-				// to recongize the channel was created.
-				time.Sleep(120 * time.Second)
-				_, err = app.slack.SetTopicOfConversation(channel.ID, topic)
+				// Keep count of failures so we can try again.
+				failed := 0
+				_, err = app.slack.SetTopicOfConversation(schan.ID, topic)
 				if err != nil {
+					failed++
 					log.Println("Failed to set topic:", err)
 				}
-				_, err = app.slack.SetPurposeOfConversation(channel.ID, topic)
+				_, err = app.slack.SetPurposeOfConversation(schan.ID, topic)
 				if err != nil {
+					failed++
 					log.Println("Failed to set purpose:", err)
 				}
+				// If it failed, make topic empty so we can try again next run.
+				if failed != 0 {
+					topic = ""
+				}
 			}
 
 			// Save the channel to the database.