Input packages don't require to define fields (#994)

With OTel inputs we have seen that all fields required are already
defined in the built-in templates, and requiring to add mappings can
lead to conflicts with them.

For ECS inputs, most required fields are also defined in ecs@mappings,
so there would be no need to require them.

These packages can still define fields if needed.

Test package for OTel is updated for current recommendations.

Author: jsoriano

compliance/compliance_test.go

@@ -146,14 +146,12 @@ func aPolicyIsCreatedWithPackageAndVersion(packageName, packageVersion string) e
 	return nil
 }
 
-func aPolicyIsCreatedWithPackageInputAndDataset(packageName, templateName, inputName, inputType, dataset string) error {
-	const version = "1.0.0" // TODO: Add support for package and version
-
+func aPolicyIsCreatedWithPackageInputAndDataset(packageName, packageVersion, templateName, inputName, inputType, dataset string) error {
 	kibana, err := NewKibanaClient()
 	if err != nil {
 		return err
 	}
-	_, err = kibana.CreatePolicyForPackageInputAndDataset(packageName, version, templateName, inputName, inputType, dataset)
+	_, err = kibana.CreatePolicyForPackageInputAndDataset(packageName, packageVersion, templateName, inputName, inputType, dataset)
 	if err != nil {
 		return err
 	}
@@ -172,7 +170,7 @@ func thereIsAnIndexTemplateWithPattern(indexTemplateName, pattern string) error
 	}
 
 	if !slices.Contains(indexTemplate.IndexPatterns, pattern) {
-		return fmt.Errorf("index template %q not found in %s", pattern, indexTemplate.IndexPatterns)
+		return fmt.Errorf("pattern %q not found in %s", pattern, indexTemplate.IndexPatterns)
 	}
 
 	return nil
@@ -310,7 +308,7 @@ func InitializeScenario(ctx *godog.ScenarioContext) {
 	ctx.Step(`^the "([^"]*)" package is installed$`, thePackageIsInstalled)
 	ctx.Step(`^a policy is created with "([^"]*)" package$`, aPolicyIsCreatedWithPackage)
 	ctx.Step(`^a policy is created with "([^"]*)" package and "([^"]*)" version$`, aPolicyIsCreatedWithPackageAndVersion)
-	ctx.Step(`^a policy is created with "([^"]*)" package, "([^"]*)" template, "([^"]*)" input, "([^"]*)" input type and dataset "([^"]*)"$`, aPolicyIsCreatedWithPackageInputAndDataset)
+	ctx.Step(`^a policy is created with "([^"]*)" package, "([^"]*)" version, "([^"]*)" template, "([^"]*)" input, "([^"]*)" input type and dataset "([^"]*)"$`, aPolicyIsCreatedWithPackageInputAndDataset)
 	ctx.Step(`^there is an index template "([^"]*)" with pattern "([^"]*)"$`, thereIsAnIndexTemplateWithPattern)
 	ctx.Step(`^there is a transform "([^"]*)"$`, thereIsATransform)
 	ctx.Step(`^there is a transform alias "([^"]*)"$`, thereIsATransformAlias)

compliance/features/basic.feature

@@ -10,9 +10,15 @@ Feature: Basic package types support
   @2.6.0
   Scenario: Input package can be installed
    Given the "basic_input" package is installed
-     And a policy is created with "basic_input" package, "test" template, "test" input, "logfile" input type and dataset "spec.input_test"
+     And a policy is created with "basic_input" package, "1.0.0" version, "test" template, "test" input, "logfile" input type and dataset "spec.input_test"
     Then there is an index template "logs-spec.input_test" with pattern "logs-spec.input_test-*"
 
+  @3.5.0
+  Scenario: OTel input package can be installed
+   Given the "good_input_otel" package is installed
+     And a policy is created with "good_input_otel" package, "0.0.1" version, "httpcheckreceiver" template, "httpcheckreceiver" input, "otelcol" input type and dataset "spec.otel_input_test"
+    Then there is an index template "metrics-spec.otel_input_test" with pattern "metrics-spec.otel_input_test.otel-*"
+
   @3.3.0
   Scenario: Basic content package can be installed
    Given the "basic_content" package is installed

spec/changelog.yml

@@ -12,6 +12,11 @@
     - description: Add support for semantic_text field definition.
       type: enhancement
       link: https://github.com/elastic/package-spec/pull/807
+- version: 3.5.1-next
+  changes:
+    - description: Input packages don't require to define fields.
+      type: enhancement
+      link: https://github.com/elastic/package-spec/pull/994
 - version: 3.5.0
   changes:
     - description: Add `duration` variable data type with `min_duration` and `max_duration` validation properties.

spec/input/spec.yml

@@ -43,7 +43,7 @@ spec:
   - description: Folder containing field definitions
     type: folder
     name: fields
-    required: true
+    required: false
     $ref: "../integration/data_stream/fields/spec.yml"
   - description: Sample event file
     type: file
@@ -75,6 +75,11 @@ spec:
     $ref: "../integration/img/spec.yml"
 
 versions:
+  - before: 3.5.0
+    patch:
+      - op: replace
+        path: "/contents/5/required" # Input packages don't require field definitions.
+        value: true
   - before: 3.2.2
     patch:
       - op: remove

test/packages/good_input_otel/fields/base-fields.yml

@@ -1,5 +1,5 @@
 format_version: 3.5.0
-name: httpcheck
+name: good_input_otel
 title: "Simple HTTP Check"
 version: 0.0.1
 source:
@@ -26,7 +26,7 @@ icons:
     size: 32x32
     type: image/svg+xml
 policy_templates:
-  - name: check
+  - name: httpcheckreceiver
     type: metrics
     title: HTTP Check
     description: Perform HTTP checks and collect its results.
@@ -60,17 +60,15 @@ policy_templates:
         multi: true
         required: true
         show_user: true
+        default:
+          - https://epr.elastic.co
       - name: headers
         type: text
         title: HTTP headers
         description: HTTP headers, defined as YAML key-values.
         multi: true
         required: false
         show_user: false
-elasticsearch:
-  index_template:
-    mappings:
-      subobjects: false
 owner:
   github: elastic/ecosystem
   type: elastic