feat(cli): support global delay range

packages/cli/src/util/__tests__/config.spec.ts

@@ -6,6 +6,7 @@ describe('assertValidConfig', () => {
       ignoreExamples: true,
       dynamic: false,
       jsonSchemaFakerFillProperties: true,
+      delay: [100, 200],
       chaos: {
         enabled: true,
         rate: 50,
@@ -16,6 +17,14 @@ describe('assertValidConfig', () => {
     expect(assertValidConfig.bind(null, validConfig)).not.toThrow();
   });
 
+  it('should accept numeric delay', () => {
+    const validConfig: Config = {
+      delay: 100,
+    };
+
+    expect(assertValidConfig.bind(null, validConfig)).not.toThrow();
+  });
+
   it('should throw an error for an invalid config', () => {
     const invalidConfig = {
       ignoreExamples: 'true', // invalid type
@@ -75,4 +84,20 @@ describe('assertValidConfig', () => {
       })
     ).toThrow();
   });
+
+  it('should require upper latency bound to be higher than lower latency bound', () => {
+    expect(
+      assertValidConfig.bind(null, {
+        delay: [100, 50],
+      })
+    ).toThrow();
+  });
+
+  it('should throw an error for a config with negative delay', () => {
+    expect(
+      assertValidConfig.bind(null, {
+        delay: -100,
+      })
+    ).toThrow();
+  });
 });

packages/cli/src/util/config.ts

@@ -8,6 +8,7 @@ export type Config = {
   ignoreExamples?: boolean;
   dynamic?: boolean;
   jsonSchemaFakerFillProperties?: boolean;
+  delay?: number | [lowerBound: number, upperBound: number];
   chaos?: {
     enabled?: boolean;
     rate?: number;
@@ -26,6 +27,7 @@ export type Config = {
 const ajv = new Ajv.Ajv2020({
   strict: true,
   allErrors: true,
+  $data: true,
 });
 
 const validate = ajv.compile({
@@ -34,6 +36,34 @@ const validate = ajv.compile({
     ignoreExamples: { type: 'boolean' },
     dynamic: { type: 'boolean' },
     jsonSchemaFakerFillProperties: { type: 'boolean' },
+    delay: {
+      oneOf: [
+        {
+          type: 'integer',
+          minimum: 0,
+          maximum: 5000,
+        },
+        {
+          type: 'array',
+          prefixItems: [
+            {
+              type: 'integer',
+              minimum: 0,
+              exclusiveMaximum: 5000,
+            },
+            {
+              type: 'integer',
+              minimum: {
+                $data: '1/0',
+              },
+              maximum: 5000,
+            },
+          ],
+          minItems: 2,
+          items: false,
+        },
+      ],
+    },
     chaos: {
       type: 'object',
       unevaluatedProperties: false,
@@ -102,10 +132,7 @@ export async function safeApplyConfig(
 
   try {
     const input = JSON.parse(content);
-    const valid = validate(input) as unknown as (input: unknown) => input is CreateMockServerOptions;
-    if (!valid) {
-      throw ajv.errorsText(validate.errors);
-    }
+    assertValidConfig(input);
 
     const merged = { ...defaultConfig, ...input };
     for (const key of Object.keys(merged)) {

packages/cli/src/util/createServer.ts

@@ -117,6 +117,9 @@ async function createPrismServerWithLogger(options: Observable<CreateBaseServerO
           )
         );
       },
+      get delay() {
+        return options.delay;
+      },
       get dynamic() {
         return options.dynamic;
       },
@@ -185,6 +188,7 @@ type CreateBaseServerOptions = {
   config?: string;
   dynamic: boolean;
   cors: boolean;
+  delay?: number | [number, number];
   chaos?: {
     enabled?: boolean;
     rate?: number;

test-harness/specs/config/delay_constant.txt

@@ -0,0 +1,33 @@
+====test====
+Given I mock and specify a constant delay
+When I send a request to an operation
+Then the response should be delayed by that amount
+====spec====
+openapi: "3.1.0"
+info:
+  version: "0.0"
+  title: Config Test
+paths:
+  /pets/{petId}:
+    get:
+      description: Get a pet by ID
+      responses:
+        "200":
+          description: A pet
+          content:
+            application/json:
+              schema:
+                type: integer
+                default: 0
+====config====
+{
+  "delay": 500
+}
+====server====
+mock -p 4010 --config ${config} ${document}
+====command====
+curl -i -s -w "%{time_total}" "http://127.0.0.1:4010/pets/2" | awk '{gsub(/0([0-9]+\.[0-9]+)/, $1 * 1000 > 500 ? "Value is higher than 500" : "Value is not higher than 500"); print}'
+====expect-loose====
+HTTP/1.1 200 OK
+
+Value is higher than 500

test-harness/specs/config/delay_range.txt

@@ -0,0 +1,33 @@
+====test====
+Given I mock and specify a constant delay
+When I send a request to an operation
+Then the response should be delayed by that amount
+====spec====
+openapi: "3.1.0"
+info:
+  version: "0.0"
+  title: Config Test
+paths:
+  /pets/{petId}:
+    get:
+      description: Get a pet by ID
+      responses:
+        "200":
+          description: A pet
+          content:
+            application/json:
+              schema:
+                type: integer
+                default: 0
+====config====
+{
+  "delay": [300, 500]
+}
+====server====
+mock -p 4010 --config ${config} ${document}
+====command====
+curl -i -s -w "%{time_total}" "http://127.0.0.1:4010/pets/2" | awk '{gsub(/0([0-9]+\.[0-9]+)/, $1 * 1000 > 300 ? "Value is higher than 300" : "Value is not higher than 300"); print}'
+====expect-loose====
+HTTP/1.1 200 OK
+
+Value is higher than 300

test-harness/specs/delay/delay_config.txt

@@ -0,0 +1,35 @@
+====test====
+When I send a request to an operation
+And I have a config with a delay of 2500ms
+And in the headers I specify `Prefer: delay=100`
+Then I get a response with a delay of 100ms
+====spec====
+openapi: "3.1.1"
+info:
+  version: "0"
+  title: Delays test
+  description: Delays test
+paths:
+  /delay:
+    get:
+      description: widget details
+      responses:
+        "200":
+          description: delay response
+          content:
+            application/json:
+              schema:
+                type: integer
+                default: 0
+====config====
+{
+  "delay": 2500
+}
+====server====
+mock -p 4010 ${document}
+====command====
+curl -i -s -w "%{time_total}" -H "Prefer: delay=100" "http://127.0.0.1:4010/delay" | awk '{gsub(/0([0-9]+\.[0-9]+)/, ($1 * 1000 < 2500 ? "Value is lower than 2500" : "Value is higher than 2500")); print}'
+====expect-loose====
+HTTP/1.1 200 OK
+
+Value is lower than 2500