Add webhook action for HTTP request integration

[mweimerskirch]

This PR adds a new webhook action that enables LocalAGI agents to send HTTP requests to external services.

The action requires static configuration:

• url (required): Target endpoint
• method: HTTP method (defaults to POST)
• contentType: Content-Type header value
• payloadTemplate: Optional body template with {{payload}} placeholder

Runtime parameters accept only the dynamic payload value, keeping the action simple.

This action enables agents to:

• Trigger external webhooks and integrations
• Post data to third-party APIs
• Perform GET requests to fetch external data

Note, I currently only tested it in the "actions playground", I didn't test it inside an agent yet.

[Copilot]

Pull Request Overview

This PR introduces a new webhook action that enables LocalAGI agents to send HTTP requests to external services. The action supports configurable URL, HTTP method, content type, and payload templates with runtime payload substitution.

Key changes:

• Added a new WebhookAction struct with support for GET, POST, PUT, and DELETE requests
• Implemented payload templating with {{payload}} placeholder replacement
• Integrated the webhook action into the main actions registry and configuration system

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
services/actions/webhook.go	Complete implementation of the webhook action with HTTP client functionality, payload templating, and configuration metadata
services/actions.go	Registration of the new webhook action in the actions system, including constants, available actions list, and factory function

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[Copilot]

The contentType field is marked as required, but many valid HTTP requests don't need a Content-Type header (e.g., GET requests with no body, or requests where the server doesn't care about the content type). Consider making this field optional to provide more flexibility.

Suggested change

	Required: true,
	Required: false,

[Copilot]

Creating a new HTTP client for each request is inefficient and prevents connection reuse. Consider using a shared http.Client instance or http.DefaultClient to enable connection pooling and improve performance.

Suggested change

	// Use a new http.Client with default settings. Consider configuring timeouts
	// at the caller level via the context, or wiring a custom client if needed.
	client := &http.Client{}
	resp, err := client.Do(req)
	// Use the shared http.DefaultClient to enable connection reuse and pooling.
	// Consider configuring timeouts at the caller level via the context, or wiring a custom client if needed.
	resp, err := http.DefaultClient.Do(req)

[Copilot]

The logic for handling payload template replacement is confusing. When no placeholder is found but payload is provided, the runtime payload is ignored. This behavior should be documented more clearly or reconsidered - users might expect their runtime payload to be used even without a template.

Suggested change

	payload = strings.ReplaceAll(a.payloadTemplate, "{{payload}}", in.Payload)
	if payload == a.payloadTemplate && in.Payload != "" {
	// If no placeholder found, fallback to template or payload alone
	if strings.Contains(a.payloadTemplate, "{{payload}}") {
	payload = strings.ReplaceAll(a.payloadTemplate, "{{payload}}", in.Payload)
	} else if in.Payload != "" {
	// Template does not contain placeholder, but runtime payload is provided.
	// Use the runtime payload as the body.
	payload = in.Payload
	} else {
	// No placeholder and no runtime payload; use template as-is.

[mweimerskirch]

This is intended. The agent should not be able to add a payload if no template is configured.

Note that the placeholder is not optimal at the moment. It allows injections.
E.g. if the template is something like {"message": "{{payload}}"} and the payload is ", "newkey": "somethingand the resulting JSON that is sent would be {"message": "", "newkey": "something"}.

Better ideas are welcome.

[mudler]

Looks good here, thanks!