generate excel worksheets when data is available instead of on-demand

internal/report/snapshots.go

@@ -6,6 +6,8 @@ import (
 	"database/sql"
 	"fmt"
 	"log/slog"
+	"os"
+	"path/filepath"
 	"strconv"
 	"strings"
 	"time"
@@ -637,6 +639,29 @@ func CreateTableReport(logger *slog.Logger, Database db.Database, ctx context.Co
 	return buffer.Bytes(), nil
 }
 
+// SaveTableReport renders a table report and writes it to the destination directory with a .xlsx extension.
+func SaveTableReport(logger *slog.Logger, Database db.Database, ctx context.Context, tableName, destDir string) (string, error) {
+	if err := db.ValidateTableName(tableName); err != nil {
+		return "", err
+	}
+	if strings.TrimSpace(destDir) == "" {
+		return "", fmt.Errorf("destination directory is empty")
+	}
+	if err := os.MkdirAll(destDir, 0o755); err != nil {
+		return "", fmt.Errorf("failed to create reports directory: %w", err)
+	}
+
+	data, err := CreateTableReport(logger, Database, ctx, tableName)
+	if err != nil {
+		return "", err
+	}
+	filename := filepath.Join(destDir, fmt.Sprintf("%s.xlsx", tableName))
+	if err := os.WriteFile(filename, data, 0o644); err != nil {
+		return "", err
+	}
+	return filename, nil
+}
+
 func addTotalsChartSheet(logger *slog.Logger, database db.Database, ctx context.Context, xlsx *excelize.File, tableName string) {
 	if strings.HasPrefix(tableName, "inventory_daily_summary_") {
 		suffix := strings.TrimPrefix(tableName, "inventory_daily_summary_")

internal/settings/settings.go

@@ -40,6 +40,7 @@ type SettingsYML struct {
 		HourlySnapshotMaxAgeDays         int      `yaml:"hourly_snapshot_max_age_days"`
 		DailySnapshotMaxAgeMonths        int      `yaml:"daily_snapshot_max_age_months"`
 		SnapshotCleanupCron              string   `yaml:"snapshot_cleanup_cron"`
+		ReportsDir                       string   `yaml:"reports_dir"`
 		HourlyJobTimeoutSeconds          int      `yaml:"hourly_job_timeout_seconds"`
 		HourlySnapshotTimeoutSeconds     int      `yaml:"hourly_snapshot_timeout_seconds"`
 		DailyJobTimeoutSeconds           int      `yaml:"daily_job_timeout_seconds"`

internal/tasks/inventorySnapshots.go

@@ -168,6 +168,10 @@ func (c *CronTask) RunVcenterSnapshotHourly(ctx context.Context, logger *slog.Lo
 		c.Logger.Warn("failed to register hourly snapshot", "error", err, "table", tableName)
 	}
 
+	if err := c.generateReport(ctx, tableName); err != nil {
+		c.Logger.Warn("failed to generate hourly report", "error", err, "table", tableName)
+	}
+
 	c.Logger.Debug("Finished hourly vcenter snapshot", "vcenter_count", len(c.Settings.Values.Settings.VcenterAddresses), "table", tableName, "row_count", rowCount)
 	return nil
 }
@@ -312,6 +316,10 @@ func (c *CronTask) aggregateDailySummary(ctx context.Context, targetTime time.Ti
 		c.Logger.Warn("failed to register daily snapshot", "error", err, "table", summaryTable)
 	}
 
+	if err := c.generateReport(ctx, summaryTable); err != nil {
+		c.Logger.Warn("failed to generate daily report", "error", err, "table", summaryTable)
+	}
+
 	c.Logger.Debug("Finished daily inventory aggregation", "summary_table", summaryTable)
 	return nil
 }
@@ -431,6 +439,10 @@ func (c *CronTask) aggregateMonthlySummary(ctx context.Context, targetMonth time
 		c.Logger.Warn("failed to register monthly snapshot", "error", err, "table", monthlyTable)
 	}
 
+	if err := c.generateReport(ctx, monthlyTable); err != nil {
+		c.Logger.Warn("failed to generate monthly report", "error", err, "table", monthlyTable)
+	}
+
 	c.Logger.Debug("Finished monthly inventory aggregation", "summary_table", monthlyTable)
 	return nil
 }
@@ -718,6 +730,21 @@ func normalizeResourcePool(value string) string {
 	}
 }
 
+func (c *CronTask) reportsDir() string {
+	if c.Settings != nil && c.Settings.Values != nil {
+		if dir := strings.TrimSpace(c.Settings.Values.Settings.ReportsDir); dir != "" {
+			return dir
+		}
+	}
+	return "/var/lib/vctp/reports"
+}
+
+func (c *CronTask) generateReport(ctx context.Context, tableName string) error {
+	dest := c.reportsDir()
+	_, err := report.SaveTableReport(c.Logger, c.Database, ctx, tableName, dest)
+	return err
+}
+
 func snapshotFromVM(vmObject *mo.VirtualMachine, vc *vcenter.Vcenter, snapshotTime time.Time, inv *queries.Inventory, hostLookup map[string]vcenter.HostLookup, folderLookup vcenter.FolderLookup, rpLookup map[string]string) (inventorySnapshotRow, error) {
 	if vmObject == nil {
 		return inventorySnapshotRow{}, fmt.Errorf("missing VM object")