Add option to set the maximum number of tags to watch for an item if watch_repo is enabled

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## 0.4.0 (2019/06/08)
+
+* Add option to set the maximum number of tags to watch for an item if `watch_repo` is enabled
+
 ## 0.3.2 (2019/06/08)
 
 * Fix registry client context

README.md

@@ -160,9 +160,10 @@ items:
   * `timeout`: Timeout is the maximum amount of time for the TCP connection to establish. 0 means no timeout (default: `10`).
   * `insecure_tls`: Allow contacting docker registry over HTTP, or HTTPS with failed TLS verification (default: `false`).
 * `items`: Slice of items to watch with the following fields:
-  * `image`: Docker image to watch using `registry/path:tag` format. If registry is omitted, `docker.io` will be used. If tag is omitted, `latest` will be used. **required**
+  * `image`: Docker image to watch using `registry/path:tag` format. If registry is omitted, `docker.io` will be used and if tag is omitted, `latest` will be used. **required**
   * `registry_id`: Registry ID from `registries` to use.
   * `watch_repo`: Watch all tags of this `image` repository (default: `false`).
+  * `max_tags`: Maximum number of tags to watch if `watch_repo` enabled. 0 means all of them (default: `25`).
   * `include_tags`: List of regular expressions to include tags. Can be useful if you enable `watch_repo`.
   * `exclude_tags`: List of regular expressions to exclude tags. Can be useful if you enable `watch_repo`.
 

internal/app/diun.go

@@ -135,12 +135,12 @@ func (di *Diun) analyzeImage(imageStr string, item model.Item, reg *docker.Regis
 }
 
 func (di *Diun) analyzeRepo(image registry.Image, item model.Item, reg *docker.RegistryClient) {
-	tags, err := reg.Tags(image)
+	tags, tagsCount, err := reg.Tags(image, item.MaxTags)
 	if err != nil {
 		log.Error().Err(err).Str("image", image.String()).Msg("Cannot retrieve tags")
 		return
 	}
-	log.Debug().Str("image", image.String()).Msgf("%d tag(s) found in repository", len(tags))
+	log.Debug().Str("image", image.String()).Msgf("%d tag(s) found in repository. %d will be analyzed.", tagsCount, len(tags))
 
 	for _, tag := range tags {
 		imageStr := fmt.Sprintf("%s/%s:%s", image.Domain, image.Path, tag)

internal/config/config.go

@@ -102,6 +102,17 @@ func (cfg *Config) Check() error {
 	}
 
 	for key, item := range cfg.Items {
+		if item.Image == "" {
+			return fmt.Errorf("image is required for item %d", key)
+		}
+
+		if err := mergo.Merge(&item, model.Item{
+			WatchRepo: false,
+			MaxTags:   25,
+		}); err != nil {
+			return fmt.Errorf("cannot set default item values for %s: %v", item.Image, err)
+		}
+
 		if item.RegistryID != "" {
 			reg, found := cfg.Registries[item.RegistryID]
 			if !found {

internal/model/item.go

@@ -5,6 +5,7 @@ type Item struct {
 	Image       string   `yaml:"image,omitempty" json:",omitempty"`
 	RegistryID  string   `yaml:"registry_id,omitempty" json:",omitempty"`
 	WatchRepo   bool     `yaml:"watch_repo,omitempty" json:",omitempty"`
+	MaxTags     int      `yaml:"max_tags,omitempty" json:",omitempty"`
 	IncludeTags []string `yaml:"include_tags,omitempty" json:",omitempty"`
 	ExcludeTags []string `yaml:"exclude_tags,omitempty" json:",omitempty"`
 	Registry    Registry `yaml:"-" json:"-"`

pkg/docker/tags.go

@@ -8,20 +8,30 @@ import (
 type Tags []string
 
 // Tags returns tags of a Docker repository
-func (c *RegistryClient) Tags(image registry.Image) (Tags, error) {
+func (c *RegistryClient) Tags(image registry.Image, max int) (Tags, int, error) {
 	ctx, cancel := c.timeoutContext()
 	defer cancel()
 
 	imgCls, err := c.newImage(ctx, image.String())
 	if err != nil {
-		return nil, err
+		return nil, 0, err
 	}
 	defer imgCls.Close()
 
 	tags, err := docker.GetRepositoryTags(ctx, c.sysCtx, imgCls.Reference())
 	if err != nil {
-		return nil, err
+		return nil, 0, err
 	}
 
-	return Tags(tags), err
+	// Reverse order (latest tags first)
+	for i := len(tags)/2 - 1; i >= 0; i-- {
+		opp := len(tags) - 1 - i
+		tags[i], tags[opp] = tags[opp], tags[i]
+	}
+
+	if max > 0 && len(tags) >= max {
+		return Tags(tags[:max]), len(tags), nil
+	}
+
+	return Tags(tags), len(tags), nil
 }