feat: create rule asyncapi3-channel-servers for v3 core ruleset

.changeset/rich-elephants-applaud.md

@@ -0,0 +1,5 @@
+---
+"@asyncapi/parser": minor
+---
+
+feat: create the rule `asyncapi3-channel-servers` for the v3 rule core ruleset

packages/parser/src/ruleset/v3/functions/channelServers.ts

@@ -0,0 +1,54 @@
+import { createRulesetFunction } from '@stoplight/spectral-core';
+
+import type { IFunctionResult } from '@stoplight/spectral-core';
+
+export const channelServers = createRulesetFunction<
+  { servers?: Record<string, unknown>; channels?: Record<string, { servers?: Array<string> }> },
+  null
+>(
+  {
+    input: {
+      type: 'object',
+      properties: {
+        servers: {
+          type: 'object',
+        },
+        channels: {
+          type: 'object',
+          additionalProperties: {
+            type: 'object',
+            properties: {
+              servers: {
+                type: 'array',
+                items: {
+                  type: 'string',
+                },
+              },
+            },
+          },
+        },
+      },
+    },
+    options: null,
+  },
+  (targetVal) => {
+    const results: IFunctionResult[] = [];
+    if (!targetVal.channels) return results;
+    const serverNames = Object.keys(targetVal.servers ?? {});
+
+    Object.entries(targetVal.channels ?? {}).forEach(([channelAddress, channel]) => {
+      if (!channel.servers) return;
+
+      channel.servers.forEach((serverName, index) => {
+        if (!serverNames.includes(serverName)) {
+          results.push({
+            message: 'Channel contains server that are not defined on the "servers" object.',
+            path: ['channels', channelAddress, 'servers', index],
+          });
+        }
+      });
+    });
+
+    return results;
+  },
+);

packages/parser/src/ruleset/v3/ruleset.ts

@@ -3,6 +3,7 @@
 import { AsyncAPIFormats } from '../formats';
 import { operationMessagesUnambiguity } from './functions/operationMessagesUnambiguity';
 import { pattern } from '@stoplight/spectral-functions';
+import { channelServers } from './functions/channelServers';
 
 export const v3CoreRuleset = {
   description: 'Core AsyncAPI 3.x.x ruleset.',
@@ -57,6 +58,16 @@ export const v3CoreRuleset = {
         },
       },
     },
+    'asyncapi3-channel-servers': {
+      description: 'Channel servers must be defined in the "servers" object.',
+      message: '{{error}}',
+      severity: 'error',
+      recommended: true,
+      given: '$',
+      then: {
+        function: channelServers,
+      },
+    },
     'asyncapi3-channel-no-query-nor-fragment': {
       description: 'Channel address should not include query ("?") or fragment ("#") delimiter.',
       severity: 'error',

packages/parser/test/ruleset/rules/v3/asyncapi3-channel-servers.spec.ts

@@ -0,0 +1,140 @@
+import { testRule, DiagnosticSeverity } from '../../tester';
+
+testRule('asyncapi3-channel-servers', [
+  {
+    name: 'valid case',
+    document: {
+      asyncapi: '3.0.0',
+      servers: {
+        development: {},
+        production: {},
+      },
+      channels: {
+        channel: {
+          servers: ['development'],
+        },
+      },
+    },
+    errors: [],
+  },
+
+  {
+    name: 'valid case - without defined servers',
+    document: {
+      asyncapi: '3.0.0',
+      servers: {
+        development: {},
+        production: {},
+      },
+      channels: {
+        channel: {},
+      },
+    },
+    errors: [],
+  },
+
+  {
+    name: 'valid case - without defined servers in the root',
+    document: {
+      asyncapi: '3.0.0',
+      channels: {
+        channel: {},
+      },
+    },
+    errors: [],
+  },
+
+  {
+    name: 'valid case - without defined channels in the root',
+    document: {
+      asyncapi: '3.0.0',
+      servers: {
+        development: {},
+        production: {},
+      },
+    },
+    errors: [],
+  },
+
+  {
+    name: 'valid case - with empty array',
+    document: {
+      asyncapi: '3.0.0',
+      servers: {
+        development: {},
+        production: {},
+      },
+      channels: {
+        channel: {
+          servers: [],
+        },
+      },
+    },
+    errors: [],
+  },
+
+  {
+    name: 'invalid case',
+    document: {
+      asyncapi: '3.0.0',
+      servers: {
+        development: {},
+        production: {},
+      },
+      channels: {
+        channel: {
+          servers: ['another-server'],
+        },
+      },
+    },
+    errors: [
+      {
+        message: 'Channel contains server that are not defined on the "servers" object.',
+        path: ['channels', 'channel', 'servers', '0'],
+        severity: DiagnosticSeverity.Error,
+      },
+    ],
+  },
+
+  {
+    name: 'invalid case - one server is defined, another one not',
+    document: {
+      asyncapi: '3.0.0',
+      servers: {
+        development: {},
+        production: {},
+      },
+      channels: {
+        channel: {
+          servers: ['production', 'another-server'],
+        },
+      },
+    },
+    errors: [
+      {
+        message: 'Channel contains server that are not defined on the "servers" object.',
+        path: ['channels', 'channel', 'servers', '1'],
+        severity: DiagnosticSeverity.Error,
+      },
+    ],
+  },
+
+  {
+    name: 'invalid case - without defined servers',
+    document: {
+      asyncapi: '3.0.0',
+      channels: {
+        channel: {
+          servers: ['production'],
+        },
+      },
+    },
+    errors: [
+      {
+        message: 'Channel contains server that are not defined on the "servers" object.',
+        path: ['channels', 'channel', 'servers', '0'],
+        severity: DiagnosticSeverity.Error,
+      },
+    ],
+  },
+]);