obtain historic_reports capability from Reporter

app/collector.go

@@ -29,6 +29,7 @@ const reportQuantisationInterval = 3 * time.Second
 // interface for parts of the app, and several experimental components.
 type Reporter interface {
 	Report(context.Context, time.Time) (report.Report, error)
+	HasHistoricReports() bool
 	WaitOn(context.Context, chan struct{})
 	UnWait(context.Context, chan struct{})
 }
@@ -139,6 +140,12 @@ func (c *collector) Report(_ context.Context, timestamp time.Time) (report.Repor
 	return rpt, nil
 }
 
+// HasHistoricReports indicates whether the collector contains reports
+// older than now-app.window.
+func (c *collector) HasHistoricReports() bool {
+	return false
+}
+
 // remove reports older than the app.window
 func (c *collector) clean() {
 	var (
@@ -195,6 +202,12 @@ func (c StaticCollector) Report(context.Context, time.Time) (report.Report, erro
 	return report.Report(c), nil
 }
 
+// HasHistoricReports indicates whether the collector contains reports
+// older than now-app.window.
+func (c StaticCollector) HasHistoricReports() bool {
+	return false
+}
+
 // Add adds a report to the collector's internal state. It implements Adder.
 func (c StaticCollector) Add(context.Context, report.Report, []byte) error { return nil }
 

app/multitenant/aws_collector.go

@@ -340,6 +340,10 @@ func (c *awsCollector) Report(ctx context.Context, timestamp time.Time) (report.
 	return c.merger.Merge(reports).Upgrade(), nil
 }
 
+func (c *awsCollector) HasHistoricReports() bool {
+	return true
+}
+
 // calculateDynamoKeys generates the row & column keys for Dynamo.
 func calculateDynamoKeys(userid string, now time.Time) (string, string) {
 	rowKey := fmt.Sprintf("%s-%s", userid, strconv.FormatInt(now.UnixNano()/time.Hour.Nanoseconds(), 10))

prog/app.go

@@ -295,7 +295,7 @@ func appMain(flags appFlags) {
 	}
 
 	capabilities := map[string]bool{
-		xfer.HistoricReportsCapability: flags.s3URL != "local",
+		xfer.HistoricReportsCapability: collector.HasHistoricReports(),
 	}
 	handler := router(collector, controlRouter, pipeRouter, flags.externalUI, capabilities)
 	if flags.logHTTP {