docs(datasource): Add additional examples for custom datasource

lib/modules/datasource/custom/readme.md

@@ -82,7 +82,7 @@ All available options:
 
 ## Examples
 
-# K3s
+### K3s
 
 You can use this configuration to request the newest version available to [K3s](https://k3s.io/)
 
@@ -98,3 +98,91 @@ You can use this configuration to request the newest version available to [K3s](
   },
 }
 ```
+
+### Hashicorp
+
+You can use this configuration to request the newest versions of the hashicorp products:
+
+```json
+{
+  "regexManagers": [
+    {
+      "fileMatch": ["\\.yml$"],
+      "datasourceTemplate": "custom.hashicorp",
+      "matchStrings": [
+        "#\\s*renovate:\\s*(datasource=(?<datasource>.*?) )?depName=(?<depName>.*?)( versioning=(?<versioning>.*?))?\\s*\\w*:\\s*(?<currentValue>.*)\\s"
+      ],
+      "versioningTemplate": "{{#if versioning}}{{{versioning}}}{{else}}semver{{/if}}"
+    }
+  ],
+  "customDatasources": {
+    "hashicorp": {
+      "defaultRegistryUrlTemplate": "https://api.releases.hashicorp.com/v1/releases/{{packageName}}?license_class=oss",
+      "transformTemplates": [
+        "{ \"releases\": $map($, function($v) { { \"version\": $v.version, \"releaseTimestamp\": $v.timestamp_created, \"changelogUrl\": $v.url_changelog, \"sourceUrl\": $v.url_source_repository } }), \"homepage\": $[0].url_project_website, \"sourceUrl\": $[0].url_source_repository }"
+      ]
+    }
+  },
+}
+```
+
+E.g. to have the latest Nomad version in your ansible variables, use this snippet after adding the above configuration:
+
+```yaml
+# renovate: depName=nomad
+nomad_version: 1.6.0
+```
+
+### Custom Offline Dependencies
+
+Sometimes the source of the dependency versions is not available via an API but has to be generated manually. For this purpose, you can manually create dependency "files" (similar to an API) served via http(s) for renovate to access. For example, imagine the following file `versiontracker.json` for the software `something``:
+
+```json
+[
+    {
+        "version": "77"
+    },
+    {
+        "version": "76"
+    },
+]
+```
+
+Which can be ingested by renovate using the following custom datasource (using nexus as a webserver in this case):
+
+```json
+{
+  "customDatasources": {
+    "nexus_generic": {
+      "defaultRegistryUrlTemplate": "https://nexus.example.com/repository/versiontrackers/{{packageName}}/versiontracker.json",
+      "transformTemplates": [
+        "{ \"releases\": $map($, function($v) { { \"version\": $v.version, \"sourceUrl\": $v.filelink } }) }"
+      ]
+    }
+  },
+}
+```
+
+This could be used to update ansible yaml files with the latest version through a regex manager, e.g. with the following ansible content:
+
+```yaml
+# renovate: datasource=custom.nexus_generic depName=something versioning=loose
+something_version: "77"
+```
+
+And the following regex manager:
+
+```json
+{
+  "regexManagers": [
+    {
+      "fileMatch": ["\\.yml$"],
+      "datasourceTemplate": "custom.nexus_generic",
+      "matchStrings": [
+        "#\\s*renovate:\\s*(datasource=(?<datasource>.*?) )?depName=(?<depName>.*?)( versioning=(?<versioning>.*?))?\\s*\\w*:\\s*\"?(?<currentValue>.+?)\"?\\s"
+      ],
+      "versioningTemplate": "{{#if versioning}}{{{versioning}}}{{else}}semver{{/if}}"
+    }
+  ],
+}
+```