allow external domain override for user-facing links (#9057)

* feat: allow external domain override for user-facing links

* refactor: use plain var + setter for externalDomain

* chore: expose externalDomain in package exports

frontend/package.json

@@ -379,6 +379,10 @@
 			"types": "./package/stores.d.ts",
 			"default": "./package/stores.js"
 		},
+		"./externalDomain": {
+			"types": "./package/externalDomain.d.ts",
+			"default": "./package/externalDomain.js"
+		},
 		"./gen": {
 			"types": "./package/gen/index.d.ts",
 			"default": "./package/gen/index.js"

frontend/src/lib/components/LogViewer.svelte

@@ -15,6 +15,7 @@
 	import { Button, Drawer, DrawerContent } from './common'
 	import { copyToClipboard } from '$lib/utils'
 	import { base } from '$lib/base'
+	import { withExternalDomain } from '$lib/externalDomain'
 	import { workspaceStore } from '$lib/stores'
 	import { AnsiUp } from 'ansi_up'
 	import NoWorkerWithTagWarning from './runs/NoWorkerWithTagWarning.svelte'
@@ -204,6 +205,9 @@
 			scroll = true
 		}
 	})
+	let downloadHref = $derived(
+		withExternalDomain(`${base}/api/w/${$workspaceStore}/jobs_u/get_logs/${jobId}`)
+	)
 	let truncatedContent = $derived(truncateContent(content, loadedFromObjectStore, LOG_LIMIT))
 	let prefixInfo = $derived(findPrefixInfo(truncatedContent))
 	let downloadStartUrl = $derived(findStartUrl(truncatedContent, prefixInfo))
@@ -244,7 +248,7 @@
 		{#snippet actions()}
 			{#if jobId && download}
 				<Button
-					href="{base}/api/w/{$workspaceStore}/jobs_u/get_logs/{jobId}"
+					href={downloadHref}
 					download="windmill_logs_{jobId}.txt"
 					color="light"
 					size="xs"
@@ -323,7 +327,7 @@
 							<a
 								class="text-primary pb-0.5"
 								target="_blank"
-								href="{base}/api/w/{$workspaceStore}/jobs_u/get_logs/{jobId}"
+								href={downloadHref}
 								download="windmill_logs_{jobId}.txt"
 								><Download size="14" />
 							</a>

frontend/src/lib/externalDomain.ts

@@ -0,0 +1,17 @@
+// Optional external domain (e.g. "https://app.windmill.dev") used to build
+// absolute URLs for user-facing links when the Windmill UI is embedded on a
+// different host than the API. Undefined = same-origin (default behavior).
+// Intended to be set once at boot by SDK consumers (e.g. windmill-react-sdk),
+// before any component that builds links has rendered — there is no
+// reactivity, so changing it after mount won't update already-rendered hrefs.
+let externalDomain: string | undefined = undefined
+
+export function setExternalDomain(domain: string | undefined): void {
+	externalDomain = domain
+}
+
+export function withExternalDomain(path: string): string {
+	if (!externalDomain) return path
+	const trimmed = externalDomain.replace(/\/$/, '')
+	return `${trimmed}${path.startsWith('/') ? path : `/${path}`}`
+}