Add alternative scheduler based on the number of entries

model/feed.go

@@ -6,8 +6,11 @@ package model // import "miniflux.app/model"
 
 import (
 	"fmt"
+	"math"
+	"strings"
 	"time"
 
+	"miniflux.app/config"
 	"miniflux.app/http/client"
 )
 
@@ -19,6 +22,7 @@ type Feed struct {
 	SiteURL            string    `json:"site_url"`
 	Title              string    `json:"title"`
 	CheckedAt          time.Time `json:"checked_at"`
+	NextCheckAt        time.Time `json:"next_check_at"`
 	EtagHeader         string    `json:"etag_header"`
 	LastModifiedHeader string    `json:"last_modified_header"`
 	ParsingErrorMsg    string    `json:"parsing_error_message"`
@@ -37,6 +41,11 @@ type Feed struct {
 	ReadCount          int       `json:"-"`
 }
 
+const (
+	// SchedulerEntryCountBased represnets the name of the scheduler based on entry counts.
+	SchedulerEntryCountBased = "entry_count_based"
+)
+
 func (f *Feed) String() string {
 	return fmt.Sprintf("ID=%d, UserID=%d, FeedURL=%s, SiteURL=%s, Title=%s, Category={%s}",
 		f.ID,
@@ -91,5 +100,27 @@ func (f *Feed) CheckedNow() {
 	}
 }
 
+// ScheduleNextCheck set "next_check_at" of a feed based on the scheduler selected from the configuration.
+func (f *Feed) ScheduleNextCheck(weeklyCount int) {
+	var nextCheckAt time.Time
+	switch strings.ToLower(config.Opts.PollingScheduler()) {
+	case SchedulerEntryCountBased:
+		var intervalMinutes int
+		if weeklyCount == 0 {
+			intervalMinutes = config.Opts.SchedulerCountBasedMaxInterval()
+		} else {
+			intervalMinutes = int(math.Round(float64(7*24*60) / float64(weeklyCount)))
+		}
+		intervalMinutes = int(math.Min(float64(intervalMinutes), float64(config.Opts.SchedulerCountBasedMaxInterval())))
+		intervalMinutes = int(math.Max(float64(intervalMinutes), float64(config.Opts.SchedulerCountBasedMinInterval())))
+		nextCheckAt = time.Now().Add(time.Minute * time.Duration(intervalMinutes))
+	default:
+		// round robin
+		// omit the interval because they are same for all feeds.
+		nextCheckAt = time.Now()
+	}
+	f.NextCheckAt = nextCheckAt
+}
+
 // Feeds is a list of feed
 type Feeds []*Feed

model/feed_test.go

@@ -5,8 +5,12 @@
 package model // import "miniflux.app/model"
 
 import (
+	"fmt"
+	"os"
 	"testing"
+	"time"
 
+	"miniflux.app/config"
 	"miniflux.app/http/client"
 )
 
@@ -107,3 +111,74 @@ func TestFeedCheckedNow(t *testing.T) {
 		t.Error(`The checked date must be set`)
 	}
 }
+
+func TestFeedScheduleNextCheckDefault(t *testing.T) {
+	var err error
+	parser := config.NewParser()
+	config.Opts, err = parser.ParseEnvironmentVariables()
+	if err != nil {
+		t.Fatalf(`Parsing failure: %v`, err)
+	}
+
+	feed := &Feed{}
+	weeklyCount := 10
+	feed.ScheduleNextCheck(weeklyCount)
+
+	if feed.NextCheckAt.IsZero() {
+		t.Error(`The next_check_at must be set`)
+	}
+}
+
+func TestFeedScheduleNextCheckEntryCountBasedMaxInterval(t *testing.T) {
+	maxInterval := 5
+	minInterval := 1
+	os.Clearenv()
+	os.Setenv("POLLING_SCHEDULER", "entry_count_based")
+	os.Setenv("SCHEDULER_ENTRY_COUNT_BASED_MAX_INTERVAL", fmt.Sprintf("%d", maxInterval))
+	os.Setenv("SCHEDULER_ENTRY_COUNT_BASED_MIN_INTERVAL", fmt.Sprintf("%d", minInterval))
+
+	var err error
+	parser := config.NewParser()
+	config.Opts, err = parser.ParseEnvironmentVariables()
+	if err != nil {
+		t.Fatalf(`Parsing failure: %v`, err)
+	}
+	feed := &Feed{}
+	weeklyCount := maxInterval * 100
+	feed.ScheduleNextCheck(weeklyCount)
+
+	if feed.NextCheckAt.IsZero() {
+		t.Error(`The next_check_at must be set`)
+	}
+
+	if feed.NextCheckAt.After(time.Now().Add(time.Minute * time.Duration(maxInterval))) {
+		t.Error(`The next_check_at should not be after the now + max interval`)
+	}
+}
+
+func TestFeedScheduleNextCheckEntryCountBasedMinInterval(t *testing.T) {
+	maxInterval := 500
+	minInterval := 100
+	os.Clearenv()
+	os.Setenv("POLLING_SCHEDULER", "entry_count_based")
+	os.Setenv("SCHEDULER_ENTRY_COUNT_BASED_MAX_INTERVAL", fmt.Sprintf("%d", maxInterval))
+	os.Setenv("SCHEDULER_ENTRY_COUNT_BASED_MIN_INTERVAL", fmt.Sprintf("%d", minInterval))
+
+	var err error
+	parser := config.NewParser()
+	config.Opts, err = parser.ParseEnvironmentVariables()
+	if err != nil {
+		t.Fatalf(`Parsing failure: %v`, err)
+	}
+	feed := &Feed{}
+	weeklyCount := minInterval / 2
+	feed.ScheduleNextCheck(weeklyCount)
+
+	if feed.NextCheckAt.IsZero() {
+		t.Error(`The next_check_at must be set`)
+	}
+
+	if feed.NextCheckAt.Before(time.Now().Add(time.Minute * time.Duration(minInterval))) {
+		t.Error(`The next_check_at should not be before the now + min interval`)
+	}
+}