feat(datasource/custom): add toml support

lib/modules/datasource/custom/formats/index.ts

@@ -4,6 +4,7 @@ import { JSONFetcher } from './json';
 import { PlainFetcher } from './plain';
 import type { CustomDatasourceFetcher } from './types';
 import { YamlFetcher } from './yaml';
+import { TomlFetcher } from "./toml";
 
 export const fetchers: Record<
   CustomDatasourceFormats,
@@ -12,5 +13,6 @@ export const fetchers: Record<
   html: new HtmlFetcher(),
   json: new JSONFetcher(),
   plain: new PlainFetcher(),
+  toml: new TomlFetcher(),
   yaml: new YamlFetcher(),
 };

lib/modules/datasource/custom/formats/toml.ts

@@ -0,0 +1,23 @@
+import { readLocalFile } from '../../../../util/fs';
+import { parse as parseToml } from '../../../../util/toml';
+import type { Http } from '../../../../util/http';
+import type { CustomDatasourceFetcher } from './types';
+
+export class TomlFetcher implements CustomDatasourceFetcher {
+  async fetch(http: Http, registryURL: string): Promise<unknown> {
+    const response = await http.getToml(registryURL)
+
+    const contentType = response.headers['content-type'];
+    if (!contentType?.startsWith('application/toml')) {
+      return null;
+    }
+
+    return parseToml(response.body);
+  }
+
+  async readFile(registryURL: string): Promise<unknown> {
+    const fileContent = await readLocalFile(registryURL, 'utf8');
+
+    return parseToml(fileContent!);
+  }
+}

lib/modules/datasource/custom/index.spec.ts

@@ -233,7 +233,7 @@ describe('modules/datasource/custom/index', () => {
       expect(result).toBeNull();
     });
 
-    it('return releases for yaml API directly exposing in Renovate format', async () => {
+    it('returns releases for yaml API directly exposing in Renovate format', async () => {
       const expected = {
         releases: [
           {
@@ -309,6 +309,91 @@ describe('modules/datasource/custom/index', () => {
       expect(result).toEqual(expected);
     });
 
+    it('returns releases for toml API directly exposing in Renovate format', async () => {
+      const expected = {
+        releases: [
+          {
+            version: '1.0.0',
+          },
+          {
+            version: '2.0.0',
+          },
+          {
+            version: '3.0.0',
+          },
+        ],
+      };
+
+      const toml = codeBlock`
+        [[releases]]
+        version = "1.0.0"
+
+        [[releases]]
+        version = "2.0.0"
+
+        [[releases]]
+        version = "3.0.0"
+      `;
+
+      httpMock.scope('https://example.com').get('/v1').reply(200, toml, {
+        'Content-Type': 'application/toml',
+      });
+
+      const result = await getPkgReleases({
+        datasource: `${CustomDatasource.id}.foo`,
+        packageName: 'myPackage',
+        customDatasources: {
+          foo: {
+            defaultRegistryUrlTemplate: 'https://example.com/v1',
+            format: 'toml',
+          },
+        },
+      });
+
+      expect(result).toEqual(expected);
+    });
+
+    it('return releases for toml file directly exposing in Renovate format', async () => {
+      const expected = {
+        releases: [
+          {
+            version: '1.0.0',
+          },
+          {
+            version: '2.0.0',
+          },
+          {
+            version: '3.0.0',
+          },
+        ],
+      };
+
+      fs.readLocalFile.mockResolvedValueOnce(codeBlock`
+        [[releases]]
+        version = "1.0.0"
+
+        [[releases]]
+        version = "2.0.0"
+
+        [[releases]]
+        version = "3.0.0"
+      `);
+
+      const result = await getPkgReleases({
+        datasource: `${CustomDatasource.id}.foo`,
+        packageName: 'myPackage',
+        customDatasources: {
+          foo: {
+            defaultRegistryUrlTemplate: 'file://test.toml',
+            format: 'toml',
+          },
+        },
+      });
+
+      expect(result).toEqual(expected);
+    });
+
+
     it('return releases for json file directly exposing in Renovate format', async () => {
       const expected = {
         releases: [

lib/modules/datasource/custom/readme.md

@@ -8,9 +8,9 @@ This example shows how to update the `k3s.version` file with a custom datasource
 Options:
 
 | option                     | default  | description                                                                                                                                                              |
-| -------------------------- | -------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
+| -------------------------- | -------- |--------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
 | defaultRegistryUrlTemplate | `""`     | URL used if no `registryUrl` is provided when looking up new releases                                                                                                    |
-| format                     | `"json"` | format used by the API. Available values are: `json`, `plain`, `yaml`, `html`                                                                                            |
+| format                     | `"json"` | format used by the API. Available values are: `json`, `plain`, `yaml`, `html`, `toml`                                                                                     |
 | transformTemplates         | `[]`     | [JSONata rules](https://docs.jsonata.org/simple) to transform the API output. Each rule will be evaluated after another and the result will be used as input to the next |
 
 Available template variables:
@@ -153,6 +153,42 @@ When Renovate receives this response with the `yaml` format, it will convert it
 
 After the conversion, any `jsonata` rules defined in the `transformTemplates` section will be applied as usual to further process the JSON data.
 
+#### TOML
+
+If `toml` is used, response is parsed and converted into TOML for further processing.
+
+The below TOML document
+
+```toml
+[[releases]]
+version = "1.0.0"
+
+[[releases]]
+version = "2.0.0"
+
+[[releases]]
+version = "3.0.0"
+```
+
+Will convert applying any `jsonata` rules defined in the `transformTemplates` section will be applied.
+
+```json
+{
+  "releases": [
+    {
+      "version": "1.0.0"
+    },
+    {
+      "version": "2.0.0"
+    },
+    {
+      "version": "3.0.0"
+    }
+  ]
+}
+```
+
+
 #### HTML
 
 If the format is set to `html`, Renovate will call the HTTP endpoint with the `Accept` header value `text/html`.

lib/util/http/index.ts

@@ -316,6 +316,16 @@ export class Http<Opts extends HttpOptions = HttpOptions> {
     });
   }
 
+  async getToml(url: string, options?: Opts): Promise<HttpResponse> {
+    const opt = options ?? {};
+    return await this.get(url, {
+      headers: {
+        Accept: 'application/toml'
+      },
+      ...opt,
+    })
+  }
+
   getJson<ResT>(url: string, options?: Opts): Promise<HttpResponse<ResT>>;
   getJson<ResT, Schema extends ZodType<ResT> = ZodType<ResT>>(
     url: string,