feat: Allow yaml.SequenceNode type

docs/configuration/images.md

@@ -358,6 +358,10 @@ If the `<image_alias>.helm.image-spec` annotation is set, the two other
 annotations `<image_alias>.helm.image-name` and `<image_alias>.helm.image-tag`
 will be ignored.
 
+If the image is in the yaml list, then the index can be specified
+in the annotations `<image_alias>.helm.image-spec`, `<image_alias>.helm.image-name`
+or `<image_alias>.helm.image-tag` in square brackets.
+
 ## Examples
 
 ### Following an image's patch branch
@@ -445,6 +449,28 @@ Argo CD Image Updater will update your configuration to use the SHA256 sum of
 the image, and Kubernetes will restart your pods automatically to have them
 use the new image.
 
+### Updating the image in the yaml list
+
+*Scenario:* You want to automatically update the image `nginx:1.19` that is inside the yaml list, e.g.
+
+```yaml
+foo:
+- name: foo-1
+  image: busybox:latest
+  command: ['sh', '-c', 'echo "Custom container running"']
+- name: foo-2
+  image: nginx:1.19
+```
+
+*Solution:* Use the index in square brackets of the item that needs to be updated, i.e.
+
+```yaml
+argocd-image-updater.argoproj.io/fooalias.helm.image-spec: foo[1].image
+```
+
+This works for annotations `<image_alias>.helm.image-name`, `<image_alias>.helm.image-tag` and `<image_alias>.helm.image-spec`.
+
+
 ## Appendix
 
 ### <a name="appendix-annotations"></a>Available annotations

pkg/argocd/update.go

@@ -5,6 +5,8 @@ import (
 	"context"
 	"fmt"
 	"path/filepath"
+	"regexp"
+	"strconv"
 	"strings"
 	"sync"
 	"text/template"
@@ -632,15 +634,45 @@ func setHelmValue(currentValues *yaml.Node, key string, value interface{}) error
 
 	var err error
 	keys := strings.Split(key, ".")
-
+	// any-string[1]
+	pattern := `^(.*)\[(.*)\]$`
+	re := regexp.MustCompile(pattern)
 	for i, k := range keys {
-		if idx, found := findHelmValuesKey(current, k); found {
+		// pointer is needed to determine that the id has indeed been passed.
+		var idPtr *int
+		// by default, the search is based on the key without changes, but
+		// if string matches pattern, we consider it is an id in YAML list.
+		key := k
+		matches := re.FindStringSubmatch(k)
+		if matches != nil {
+			idStr := matches[2]
+			id, err := strconv.Atoi(idStr)
+			if err != nil {
+				return fmt.Errorf("id \"%s\" in yaml array must match pattern ^(.*)\\[(.*)\\]$", idStr)
+			}
+			idPtr = &id
+			key = matches[1]
+		}
+		if idx, found := findHelmValuesKey(current, key); found {
 			// Navigate deeper into the map
 			current = (*current).Content[idx]
 			// unpack one level of alias; an alias of an alias is not supported
 			if current.Kind == yaml.AliasNode {
 				current = current.Alias
 			}
+			if current.Kind != yaml.SequenceNode && idPtr != nil {
+				return fmt.Errorf("id %d provided when \"%s\" is not an yaml array", *idPtr, key)
+			}
+			if current.Kind == yaml.SequenceNode {
+				if idPtr == nil {
+					return fmt.Errorf("no id provided for yaml array \"%s\"", key)
+				}
+				currentContent := (*current).Content
+				if *idPtr < 0 || *idPtr >= len(currentContent) {
+					return fmt.Errorf("id %d is out of range [0, %d)", *idPtr, len(currentContent))
+				}
+				current = (*current).Content[*idPtr]
+			}
 			if i == len(keys)-1 {
 				// If we're at the final key, set the value and return
 				if current.Kind == yaml.ScalarNode {

pkg/argocd/update_test.go

@@ -2438,6 +2438,266 @@ image:
 		require.NoError(t, err)
 		assert.Equal(t, strings.TrimSpace(expected), strings.TrimSpace(string(output)))
 	})
+
+	t.Run("yaml list is correctly parsed", func(t *testing.T) {
+		expected := `
+images:
+- name: image-1
+  attributes:
+    name: repo-name
+    tag: 2.0.0
+`
+
+		inputData := []byte(`
+images:
+- name: image-1
+  attributes:
+    name: repo-name
+    tag: 1.0.0
+`)
+		input := yaml.Node{}
+		err := yaml.Unmarshal(inputData, &input)
+		require.NoError(t, err)
+
+		key := "images[0].attributes.tag"
+		value := "2.0.0"
+
+		err = setHelmValue(&input, key, value)
+		require.NoError(t, err)
+
+		output, err := marshalWithIndent(&input, defaultIndent)
+		require.NoError(t, err)
+		assert.Equal(t, strings.TrimSpace(expected), strings.TrimSpace(string(output)))
+	})
+
+	t.Run("yaml list is correctly parsed when multiple values", func(t *testing.T) {
+		expected := `
+images:
+- name: image-1
+  attributes:
+    name: repo-name
+    tag: 1.0.0
+- name: image-2
+  attributes:
+    name: repo-name
+    tag: 2.0.0
+`
+
+		inputData := []byte(`
+images:
+- name: image-1
+  attributes:
+    name: repo-name
+    tag: 1.0.0
+- name: image-2
+  attributes:
+    name: repo-name
+    tag: 1.0.0
+`)
+		input := yaml.Node{}
+		err := yaml.Unmarshal(inputData, &input)
+		require.NoError(t, err)
+
+		key := "images[1].attributes.tag"
+		value := "2.0.0"
+
+		err = setHelmValue(&input, key, value)
+		require.NoError(t, err)
+
+		output, err := marshalWithIndent(&input, defaultIndent)
+		require.NoError(t, err)
+		assert.Equal(t, strings.TrimSpace(expected), strings.TrimSpace(string(output)))
+	})
+
+	t.Run("yaml list is correctly parsed when inside map", func(t *testing.T) {
+		expected := `
+extraContainers:
+  images:
+  - name: image-1
+    attributes:
+      name: repo-name
+      tag: 2.0.0
+`
+
+		inputData := []byte(`
+extraContainers:
+  images:
+  - name: image-1
+    attributes:
+      name: repo-name
+      tag: 1.0.0
+`)
+		input := yaml.Node{}
+		err := yaml.Unmarshal(inputData, &input)
+		require.NoError(t, err)
+
+		key := "extraContainers.images[0].attributes.tag"
+		value := "2.0.0"
+
+		err = setHelmValue(&input, key, value)
+		require.NoError(t, err)
+
+		output, err := marshalWithIndent(&input, defaultIndent)
+		require.NoError(t, err)
+		assert.Equal(t, strings.TrimSpace(expected), strings.TrimSpace(string(output)))
+	})
+
+	t.Run("yaml list is correctly parsed when list name contains digits", func(t *testing.T) {
+		expected := `
+extraContainers:
+  images123:
+  - name: image-1
+    attributes:
+      name: repo-name
+      tag: 2.0.0
+`
+
+		inputData := []byte(`
+extraContainers:
+  images123:
+  - name: image-1
+    attributes:
+      name: repo-name
+      tag: 1.0.0
+`)
+		input := yaml.Node{}
+		err := yaml.Unmarshal(inputData, &input)
+		require.NoError(t, err)
+
+		key := "extraContainers.images123[0].attributes.tag"
+		value := "2.0.0"
+
+		err = setHelmValue(&input, key, value)
+		require.NoError(t, err)
+
+		output, err := marshalWithIndent(&input, defaultIndent)
+		require.NoError(t, err)
+		assert.Equal(t, strings.TrimSpace(expected), strings.TrimSpace(string(output)))
+	})
+
+	t.Run("id for yaml list is lower than 0", func(t *testing.T) {
+		inputData := []byte(`
+images:
+- name: image-1
+  attributes:
+    name: repo-name
+    tag: 1.0.0
+`)
+		input := yaml.Node{}
+		err := yaml.Unmarshal(inputData, &input)
+		require.NoError(t, err)
+
+		key := "images[-1].attributes.tag"
+		value := "2.0.0"
+
+		err = setHelmValue(&input, key, value)
+
+		require.Error(t, err)
+		assert.Equal(t, "id -1 is out of range [0, 1)", err.Error())
+	})
+
+	t.Run("id for yaml list is greater than length of list", func(t *testing.T) {
+		inputData := []byte(`
+images:
+- name: image-1
+  attributes:
+    name: repo-name
+    tag: 1.0.0
+`)
+		input := yaml.Node{}
+		err := yaml.Unmarshal(inputData, &input)
+		require.NoError(t, err)
+
+		key := "images[1].attributes.tag"
+		value := "2.0.0"
+
+		err = setHelmValue(&input, key, value)
+
+		require.Error(t, err)
+		assert.Equal(t, "id 1 is out of range [0, 1)", err.Error())
+	})
+
+	t.Run("id for YAML list is not a valid integer", func(t *testing.T) {
+		inputData := []byte(`
+images:
+- name: image-1
+  attributes:
+    name: repo-name
+    tag: 1.0.0
+`)
+		input := yaml.Node{}
+		err := yaml.Unmarshal(inputData, &input)
+		require.NoError(t, err)
+
+		key := "images[invalid].attributes.tag"
+		value := "2.0.0"
+
+		err = setHelmValue(&input, key, value)
+
+		require.Error(t, err)
+		assert.Equal(t, "id \"invalid\" in yaml array must match pattern ^(.*)\\[(.*)\\]$", err.Error())
+	})
+
+	t.Run("no id for yaml list given", func(t *testing.T) {
+		inputData := []byte(`
+images:
+- name: image-1
+  attributes:
+    name: repo-name
+    tag: 1.0.0
+`)
+		input := yaml.Node{}
+		err := yaml.Unmarshal(inputData, &input)
+		require.NoError(t, err)
+
+		key := "images.attributes.tag"
+		value := "2.0.0"
+
+		err = setHelmValue(&input, key, value)
+
+		require.Error(t, err)
+		assert.Equal(t, "no id provided for yaml array \"images\"", err.Error())
+	})
+
+	t.Run("id given when node is not an yaml list", func(t *testing.T) {
+		inputData := []byte(`
+image:
+  attributes:
+    name: repo-name
+    tag: 1.0.0
+`)
+		input := yaml.Node{}
+		err := yaml.Unmarshal(inputData, &input)
+		require.NoError(t, err)
+
+		key := "image[0].attributes.tag"
+		value := "2.0.0"
+
+		err = setHelmValue(&input, key, value)
+
+		require.Error(t, err)
+		assert.Equal(t, "id 0 provided when \"image\" is not an yaml array", err.Error())
+	})
+
+	t.Run("invalid id given when node is not an yaml list", func(t *testing.T) {
+		inputData := []byte(`
+image:
+  attributes:
+    name: repo-name
+    tag: 1.0.0
+`)
+		input := yaml.Node{}
+		err := yaml.Unmarshal(inputData, &input)
+		require.NoError(t, err)
+
+		key := "image[invalid].attributes.tag"
+		value := "2.0.0"
+
+		err = setHelmValue(&input, key, value)
+
+		require.Error(t, err)
+		assert.Equal(t, "id \"invalid\" in yaml array must match pattern ^(.*)\\[(.*)\\]$", err.Error())
+	})
 }
 
 func Test_GetWriteBackConfig(t *testing.T) {