Adds examples to schema.json and OpenAPI outputs (#3737)

* This featre scans All the API folders in the specfication to locate API request and response examples. It then adds the 'examples' info to schema.json and to the OpenAPI JSON files.

---------

Co-authored-by: Lisa Cawley <lcawley@elastic.co>
Co-authored-by: Sylvain Wallez <sylvain@elastic.co>

Author: 3 people

compiler-rs/clients_schema/src/lib.rs

@@ -482,6 +482,23 @@ impl TypeDefinition {
     }
 }
 
+/// The Example type is used for both requests and responses.
+///
+/// This type definition is taken from the OpenAPI spec
+///     https://spec.openapis.org/oas/v3.1.0#example-object
+/// with the exception of using String as the 'value' type.
+///
+/// The OpenAPI v3 spec also defines the 'Example' type, so
+/// to distinguish them, this type is called SchemaExample.
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct SchemaExample {
+    pub summary: Option<String>,
+    pub description: Option<String>,
+    pub value: Option<String>,
+    pub external_value: Option<String>,
+}
+
 /// Common attributes for all type definitions
 #[derive(Debug, Clone, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
@@ -675,6 +692,8 @@ pub struct Request {
 
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub attached_behaviors: Vec<String>,
+
+    pub examples: Option<IndexMap<String, SchemaExample>>
 }
 
 impl WithBaseType for Request {
@@ -703,6 +722,8 @@ pub struct Response {
 
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub exceptions: Vec<ResponseException>,
+
+    pub examples: Option<IndexMap<String, SchemaExample>>
 }
 
 impl WithBaseType for Response {

compiler-rs/clients_schema_to_openapi/src/paths.rs

@@ -20,12 +20,15 @@ use std::fmt::Write;
 
 use anyhow::{anyhow, bail};
 use clients_schema::Property;
+use indexmap::IndexMap;
 use indexmap::indexmap;
 use icu_segmenter::SentenceSegmenter;
 use openapiv3::{
     MediaType, Parameter, ParameterData, ParameterSchemaOrContent, PathItem, PathStyle, Paths, QueryStyle, ReferenceOr,
-    RequestBody, Response, Responses, StatusCode,
+    RequestBody, Response, Responses, StatusCode, Example
 };
+use clients_schema::SchemaExample;
+use serde_json::json;
 
 use crate::components::TypesAndComponents;
 
@@ -116,15 +119,42 @@ pub fn add_endpoint(
 
     //---- Prepare request body
 
+    // This function converts the IndexMap<String, SchemaExample> examples of
+    // schema.json to IndexMap<String, ReferenceOr<Example>> which is the format
+    // that OpenAPI expects.
+    fn get_openapi_examples(schema_examples: IndexMap<String, SchemaExample>) -> IndexMap<String, ReferenceOr<Example>> {
+        let mut openapi_examples = indexmap! {};
+        for (name, schema_example) in schema_examples {
+            let openapi_example = Example {
+                value: Some(json!(schema_example.value)),
+                description: schema_example.description.clone(),
+                summary: schema_example.summary.clone(),
+                external_value: None,
+                extensions: Default::default(),
+            };
+            openapi_examples.insert(name.clone(), ReferenceOr::Item(openapi_example));    
+        }
+        return openapi_examples;
+    }
+
+
+    let mut request_examples: IndexMap<String, ReferenceOr<Example>> = indexmap! {};
+    // If this endpoint request has examples in schema.json, convert them to the 
+    // OpenAPI format and add them to the endpoint request in the OpenAPI document.
+    if request.examples.is_some() {
+        request_examples = get_openapi_examples(request.examples.as_ref().unwrap().clone());
+    }
+
     let request_body = tac.convert_request(request)?.map(|schema| {
         let media = MediaType {
             schema: Some(schema),
             example: None,
-            examples: Default::default(),
+            examples: request_examples,
             encoding: Default::default(),
             extensions: Default::default(),
         };
 
+
         let body = RequestBody {
             description: None,
             // FIXME: nd-json requests
@@ -142,17 +172,24 @@ pub fn add_endpoint(
 
     //---- Prepare request responses
 
+
     // FIXME: buggy for responses with no body
     // TODO: handle binary responses
     let response_def = tac.model.get_response(endpoint.response.as_ref().unwrap())?;
+    let mut response_examples: IndexMap<String, ReferenceOr<Example>> = indexmap! {};
+    // If this endpoint response has examples in schema.json, convert them to the 
+    // OpenAPI format and add them to the endpoint response in the OpenAPI document.
+    if response_def.examples.is_some() {
+        response_examples = get_openapi_examples(response_def.examples.as_ref().unwrap().clone());
+    }
     let response = Response {
         description: "".to_string(),
         headers: Default::default(),
         content: indexmap! {
             "application/json".to_string() => MediaType {
                 schema: tac.convert_response(response_def)?,
                 example: None,
-                examples: Default::default(),
+                examples: response_examples,
                 encoding: Default::default(),
                 extensions: Default::default(),
             }

compiler-rs/compiler-wasm-lib/pkg/compiler_wasm_lib_bg.wasm

@@ -28,6 +28,7 @@ import validateModel from './steps/validate-model'
 import addContentType from './steps/add-content-type'
 import readDefinitionValidation from './steps/read-definition-validation'
 import addDeprecation from './steps/add-deprecation'
+import ExamplesProcessor from './steps/add-examples'
 
 const nvmrc = readFileSync(join(__dirname, '..', '..', '.nvmrc'), 'utf8')
 const nodejsMajor = process.version.split('.').shift()?.slice(1) ?? ''
@@ -65,6 +66,9 @@ if (outputFolder === '' || outputFolder === undefined) {
 
 const compiler = new Compiler(specsFolder, outputFolder)
 
+const examplesProcessor = new ExamplesProcessor(specsFolder)
+const addExamples = examplesProcessor.addExamples.bind(examplesProcessor)
+
 compiler
   .generateModel()
   .step(addInfo)
@@ -74,6 +78,7 @@ compiler
   .step(validateRestSpec)
   .step(addDescription)
   .step(validateModel)
+  .step(addExamples)
   .write()
   .then(() => {
     console.log('Done')

compiler/src/index.ts

@@ -260,6 +260,23 @@ export class Interface extends BaseType {
   variants?: Container
 }
 
+/**
+ * The Example type is used for both requests and responses
+ * This type definition is taken from the OpenAPI spec
+ *     https://spec.openapis.org/oas/v3.1.0#example-object
+ * With the exception of using String as the 'value' type
+ */
+export class Example {
+  /** Short description. */
+  summary?: string
+  /** Long description. */
+  description?: string
+  /** Embedded literal example. Mutually exclusive with `external_value` */
+  value?: string
+  /** A URI that points to the literal example */
+  external_value?: string
+}
+
 /**
  * A request type
  */
@@ -288,6 +305,7 @@ export class Request extends BaseType {
   body: Body
   behaviors?: Behavior[]
   attachedBehaviors?: string[]
+  examples?: Record<string, Example>
 }
 
 /**
@@ -300,6 +318,7 @@ export class Response extends BaseType {
   behaviors?: Behavior[]
   attachedBehaviors?: string[]
   exceptions?: ResponseException[]
+  examples?: Record<string, Example>
 }
 
 export class ResponseException {