Configurable tags for Lambda functions (#13352)

New option is added to configure tags for functions named `tags`. It expects key-value pairs.

```yaml
# Tags are key-value pairs attached to the function.
#tags:
#  department: ops
```

Closes #13080

CHANGELOG.next.asciidoc

@@ -348,6 +348,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 - Export automation templates used to create functions. {pull}11923[11923]
 - Configurable Amazon endpoint. {pull}12369[12369]
 - Add timeout option to reference configuration. {pull}13351[13351]
+- Configurable tags for Lambda functions. {pull}13352[13352]
 
 *Winlogbeat*
 

x-pack/functionbeat/_meta/beat.reference.yml

@@ -50,6 +50,10 @@ functionbeat.provider.aws.functions:
     # Dead letter queue configuration, this must be set to an ARN pointing to a SQS queue.
     #dead_letter_config.target_arn:
 
+    # Tags are key-value pairs attached to the function.
+    #tags:
+    #  department: ops
+
     # Optional fields that you can specify to add additional information to the
     # output. Fields can be scalar values, arrays, dictionaries, or any nested
     # combination of these.
@@ -98,6 +102,10 @@ functionbeat.provider.aws.functions:
     # Dead letter queue configuration, this must be set to an ARN pointing to a SQS queue.
     #dead_letter_config.target_arn:
 
+    # Tags are key-value pairs attached to the function.
+    #tags:
+    #  department: ops
+
     # Optional fields that you can specify to add additional information to the
     # output. Fields can be scalar values, arrays, dictionaries, or any nested
     # combination of these.
@@ -151,6 +159,10 @@ functionbeat.provider.aws.functions:
     # Dead letter queue configuration, this must be set to an ARN pointing to a SQS queue.
     #dead_letter_config.target_arn:
 
+    # Tags are key-value pairs attached to the function.
+    #tags:
+    #  department: ops
+
     # Optional fields that you can specify to add additional information to the
     # output. Fields can be scalar values, arrays, dictionaries, or any nested
     # combination of these.

x-pack/functionbeat/functionbeat.reference.yml

@@ -50,6 +50,10 @@ functionbeat.provider.aws.functions:
     # Dead letter queue configuration, this must be set to an ARN pointing to a SQS queue.
     #dead_letter_config.target_arn:
 
+    # Tags are key-value pairs attached to the function.
+    #tags:
+    #  department: ops
+
     # Optional fields that you can specify to add additional information to the
     # output. Fields can be scalar values, arrays, dictionaries, or any nested
     # combination of these.
@@ -98,6 +102,10 @@ functionbeat.provider.aws.functions:
     # Dead letter queue configuration, this must be set to an ARN pointing to a SQS queue.
     #dead_letter_config.target_arn:
 
+    # Tags are key-value pairs attached to the function.
+    #tags:
+    #  department: ops
+
     # Optional fields that you can specify to add additional information to the
     # output. Fields can be scalar values, arrays, dictionaries, or any nested
     # combination of these.
@@ -151,6 +159,10 @@ functionbeat.provider.aws.functions:
     # Dead letter queue configuration, this must be set to an ARN pointing to a SQS queue.
     #dead_letter_config.target_arn:
 
+    # Tags are key-value pairs attached to the function.
+    #tags:
+    #  department: ops
+
     # Optional fields that you can specify to add additional information to the
     # output. Fields can be scalar values, arrays, dictionaries, or any nested
     # combination of these.

x-pack/functionbeat/manager/aws/template_builder.go

@@ -165,6 +165,15 @@ func (d *defaultTemplateBuilder) template(function installer, name, codeLoc stri
 		}
 	}
 
+	var tags []cloudformation.Tag
+	for name, val := range lambdaConfig.Tags {
+		tag := cloudformation.Tag{
+			Key:   name,
+			Value: val,
+		}
+		tags = append(tags, tag)
+	}
+
 	// Create the lambda
 	// Doc: https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-lambda-function.html
 	template.Resources[prefix("")] = &AWSLambdaFunction{
@@ -190,6 +199,7 @@ func (d *defaultTemplateBuilder) template(function installer, name, codeLoc stri
 			MemorySize:                   lambdaConfig.MemorySize.Megabytes(),
 			ReservedConcurrentExecutions: lambdaConfig.Concurrency,
 			Timeout:                      int(lambdaConfig.Timeout.Seconds()),
+			Tags:                         tags,
 		},
 		DependsOn: dependsOn,
 	}

x-pack/functionbeat/provider/aws/aws/config.go

@@ -7,8 +7,10 @@ package aws
 import (
 	"fmt"
 	"regexp"
+	"strings"
 	"time"
 	"unicode"
+	"unicode/utf8"
 
 	humanize "github.com/dustin/go-humanize"
 
@@ -49,6 +51,7 @@ type LambdaConfig struct {
 	Timeout          time.Duration     `config:"timeout" validate:"nonzero,positive"`
 	Role             string            `config:"role"`
 	VPCConfig        *vpcConfig        `config:"virtual_private_cloud"`
+	Tags             map[string]string `config:"tags"`
 }
 
 // Validate checks a LambdaConfig
@@ -65,7 +68,7 @@ func (c *LambdaConfig) Validate() error {
 		return fmt.Errorf("invalid role: '%s', name must match pattern %s", c.Role, arnRolePattern)
 	}
 
-	return nil
+	return validateTags(c.Tags)
 }
 
 type deadLetterConfig struct {
@@ -77,6 +80,27 @@ type vpcConfig struct {
 	SubnetIDs        []string `config:"subnet_ids" validate:"required"`
 }
 
+func validateTags(tags map[string]string) error {
+	for key, val := range tags {
+		if strings.HasPrefix(key, "aws:") {
+			return fmt.Errorf("key '%s' cannot be prefixed with 'aws:'", key)
+		}
+		if strings.HasPrefix(val, "aws:") {
+			return fmt.Errorf("value '%s' cannot be prefixed with 'aws:'", val)
+		}
+		keyLen := utf8.RuneCountInString(key)
+		if keyLen > 127 {
+			return fmt.Errorf("too long key; expected 127 chars, but got %d", keyLen)
+		}
+		valLen := utf8.RuneCountInString(val)
+		if valLen > 255 {
+			return fmt.Errorf("too long value; expected 255 chars, but got %d", valLen)
+		}
+	}
+
+	return nil
+}
+
 // MemSizeFactor64 implements a human understandable format for bytes but also make sure that all
 // values used are a factory of 64.
 type MemSizeFactor64 int