add alias+datastream rollover, and auto rollover on index tpl change (#40)

fixes #37

pkg/es/datastream.go

@@ -237,3 +237,23 @@ func DatastreamDelete(conf *cfg.Config, dsname string) error {
 
 	return nil
 }
+
+func DatastreamRollover(conf *cfg.Config, ds string) error {
+	res, err := RolloverAlias(conf, ds)
+
+	if err != nil {
+		return fmt.Errorf("failed to rollover data stream: %s", esErrorString(err))
+	}
+
+	table := printer.NewTable(conf, 2, 5)
+	table.Addheaders("rollover response", "value")
+	table.Entries = [][]string{
+		{"acknowledged", fmt.Sprintf("%t", res.Acknowledged)},
+		{"rolled over", fmt.Sprintf("%t", res.RolledOver)},
+		{"shards acknowledged", fmt.Sprintf("%t", res.ShardsAcknowledged)},
+		{"old index", res.OldIndex},
+		{"new index", res.NewIndex},
+	}
+
+	return table.Print()
+}

pkg/es/index_alias.go

@@ -113,3 +113,23 @@ func IndexAliasDelete(conf *cfg.Config, index, alias string) error {
 
 	return nil
 }
+
+func IndexAliasRollover(conf *cfg.Config, alias string) error {
+	res, err := RolloverAlias(conf, alias)
+
+	if err != nil {
+		return fmt.Errorf("failed to rollover index alias: %s", esErrorString(err))
+	}
+
+	table := printer.NewTable(conf, 2, 5)
+	table.Addheaders("rollover response", "value")
+	table.Entries = [][]string{
+		{"acknowledged", fmt.Sprintf("%t", res.Acknowledged)},
+		{"rolled over", fmt.Sprintf("%t", res.RolledOver)},
+		{"shards acknowledged", fmt.Sprintf("%t", res.ShardsAcknowledged)},
+		{"old index", res.OldIndex},
+		{"new index", res.NewIndex},
+	}
+
+	return table.Print()
+}

pkg/es/index_template.go

@@ -127,26 +127,28 @@ func IndexTemplateShow(conf *cfg.Config, tplname string) error {
 	table = printer.NewTable(conf, 2, 0)
 	table.Addheaders("index field mapping", "type")
 
-	for name, field := range tpl.IndexTemplate.Template.Mappings.Properties {
-		typeval := ""
+	if tpl.IndexTemplate.Template.Mappings != nil {
+		for name, field := range tpl.IndexTemplate.Template.Mappings.Properties {
+			typeval := ""
 
-		switch val := field.(type) {
-		case *types.IntegerNumberProperty:
-			typeval = val.Type
-		case *types.KeywordProperty:
-			typeval = val.Type
-		case *types.DateProperty:
-			typeval = val.Type
+			switch val := field.(type) {
+			case *types.IntegerNumberProperty:
+				typeval = val.Type
+			case *types.KeywordProperty:
+				typeval = val.Type
+			case *types.DateProperty:
+				typeval = val.Type
+			}
+
+			table.Entries = append(table.Entries, []string{
+				name, typeval,
+			})
 		}
 
-		table.Entries = append(table.Entries, []string{
-			name, typeval,
-		})
-	}
-
-	fmt.Println()
-	if err := table.Print(); err != nil {
-		return err
+		fmt.Println()
+		if err := table.Print(); err != nil {
+			return err
+		}
 	}
 
 	return nil
@@ -343,6 +345,12 @@ func IndexTemplateModify(conf *cfg.Config, name string, mappings []string) error
 		return fmt.Errorf("failed to modify index template: %s", esErrorString(err))
 	}
 
+	if conf.Rollover {
+		if err := rolloverAliasIndexTemplate(conf, name); err != nil {
+			return err
+		}
+	}
+
 	return nil
 }
 
@@ -358,6 +366,72 @@ func IndexTemplateDelete(conf *cfg.Config, name string) error {
 	return nil
 }
 
+// Based on given  index template find the  associated index patterns,
+// find  indices matching  those,  find their  associated aliases  and
+// rollover all we find. Only run when conf.Rollover==true
+func rolloverAliasIndexTemplate(conf *cfg.Config, name string) error {
+	res, err := conf.DefaultCluster.ES.Indices.GetIndexTemplate().
+		Name(name).
+		Do(context.Background())
+
+	if err != nil {
+		return fmt.Errorf("failed to get index template: %s", esErrorString(err))
+	}
+
+	slog.Debug("res", "index template", res)
+
+	if len(res.IndexTemplates) != 1 {
+		return errors.New("multiple or no index template matched the pattern")
+	}
+
+	patterns := res.IndexTemplates[0].IndexTemplate.IndexPatterns
+	aliases := map[string]int{}
+
+	// find all aliases matching the patterns
+	for _, pattern := range patterns {
+		res, err := conf.DefaultCluster.ES.Indices.ResolveIndex(pattern).
+			Do(context.Background())
+		if err != nil {
+			return fmt.Errorf("failed to resolve index pattern: %s", esErrorString(err))
+		}
+
+		for _, index := range res.Indices {
+			for _, alias := range index.Aliases {
+				aliases[alias] = 1
+			}
+		}
+	}
+
+	if len(aliases) == 0 {
+		return nil
+	}
+
+	table := printer.NewTable(conf, 4, 0)
+	table.Addheaders("rollover alias", "status", "ack", "new index")
+
+	// apply rollover to all matching aliases, if any
+	for alias := range aliases {
+		res, err := RolloverAlias(conf, alias)
+		if err != nil {
+			return err
+		}
+
+		table.Entries = append(table.Entries, []string{
+			alias,
+			fmt.Sprintf("%t", res.RolledOver),
+			fmt.Sprintf("%t", res.Acknowledged),
+			res.NewIndex,
+		})
+
+		if err := table.Print(); err != nil {
+			return err
+		}
+	}
+
+	return nil
+
+}
+
 func modMappings(mappings []string) (types.TypeMappingVariant, error) {
 	typemaps := esdsl.NewTypeMapping()
 

pkg/es/rollover.go

@@ -0,0 +1,65 @@
+/*
+Copyright © 2026 Thomas von Dein
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+package es
+
+import (
+	"context"
+
+	"codeberg.org/scip/esctl/pkg/cfg"
+	"github.com/elastic/go-elasticsearch/v9/typedapi/esdsl"
+	"github.com/elastic/go-elasticsearch/v9/typedapi/indices/rollover"
+	"github.com/elastic/go-elasticsearch/v9/typedapi/types"
+)
+
+func RolloverConditions(conf *cfg.Config) types.RolloverConditionsVariant {
+	cond := esdsl.NewRolloverConditions()
+
+	if conf.MaxAge != "" {
+		cond.MaxAge(esdsl.NewDuration().String(conf.MaxAge))
+	}
+	if conf.MaxDocs > 0 {
+		cond.MaxDocs(int64(conf.MaxDocs))
+	}
+	if conf.MaxShardSize > 0 {
+		bs := esdsl.NewByteSize()
+		bs.Int64(int64(conf.MaxShardSize))
+		cond.MaxPrimaryShardSize(bs)
+	}
+	if conf.MaxShardDocs > 0 {
+		cond.MaxPrimaryShardDocs(int64(conf.MaxShardDocs))
+	}
+
+	return cond
+}
+
+func RolloverAlias(conf *cfg.Config, alias string) (*rollover.Response, error) {
+	roll := conf.DefaultCluster.ES.Indices.Rollover(alias)
+
+	if conf.Wait {
+		roll.WaitForActiveShards("all")
+	}
+
+	if conf.DryRun {
+		roll.DryRun(true)
+	}
+
+	cond := RolloverConditions(conf)
+
+	roll.Conditions(cond)
+
+	return roll.Do(context.Background())
+}