From 5753182e03be0517861645978383587ae4b85058 Mon Sep 17 00:00:00 2001
From: Jens L <jens@beryju.org>
Date: Tue, 12 Oct 2021 10:58:02 +0200
Subject: [PATCH] root: migrate docker images to netlify proxy (#1603)

* migrate to netlify proxy

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>

* relative forward to func

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>

* custom logic for go paths

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>

* fix const

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>

* missing break

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>

* add default for new repos

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>
---
 website/netlify.toml                   | 13 +++--
 website/netlify/functions/go-get.js    | 23 ++++++++
 website/netlify/functions/oci-proxy.js | 75 ++++++++++++++++++++++++++
 3 files changed, 108 insertions(+), 3 deletions(-)
 create mode 100644 website/netlify/functions/go-get.js
 create mode 100644 website/netlify/functions/oci-proxy.js

diff --git a/website/netlify.toml b/website/netlify.toml
index 1b07e6453..431b54756 100644
--- a/website/netlify.toml
+++ b/website/netlify.toml
@@ -1,11 +1,18 @@
 [[redirects]]
-  from = "/v2/"
-  to = "https://ghcr.registry.beryju.org/v2/"
+  from = "/*"
+  to = "/.netlify/functions/go-get"
+  status = 200
+  force = true
+  query = {go-get = "1"}
+
+[[redirects]]
+  from = "/v2"
+  to = "/.netlify/functions/oci-proxy"
   status = 200
   force = true
 
 [[redirects]]
   from = "/v2/*"
-  to = "https://ghcr.registry.beryju.org/v2/goauthentik/:splat"
+  to = "https://ghcr.io/v2/goauthentik/:splat"
   status = 200
   force = true
diff --git a/website/netlify/functions/go-get.js b/website/netlify/functions/go-get.js
new file mode 100644
index 000000000..c1dbe3471
--- /dev/null
+++ b/website/netlify/functions/go-get.js
@@ -0,0 +1,23 @@
+const gitHubNamespace = "goauthentik.io";
+
+exports.handler = async function (event, context) {
+    let repo = "";
+    switch (event.path) {
+        case "/":
+            repo = "/authentik.git";
+            break;
+        case "/api":
+            repo = "/client-go.git";
+            break;
+        default:
+            repo = `${event.path}.git`;
+            break;
+    }
+    return {
+        statusCode: 200,
+        headers: {
+            "content-type": "text/html",
+        },
+        body: `<meta name="go-import" content="${event.headers.host}${event.path} git https://github.com/${gitHubNamespace}${repo}">`
+    };
+}
diff --git a/website/netlify/functions/oci-proxy.js b/website/netlify/functions/oci-proxy.js
new file mode 100644
index 000000000..276a44a1c
--- /dev/null
+++ b/website/netlify/functions/oci-proxy.js
@@ -0,0 +1,75 @@
+const config = {
+    namespace: "goauthentik/",
+    // Settings for GHCR
+    registryTokenEndpoint: "https://ghcr.io/token",
+    registryService: "ghcr.io",
+    // Settings for Harbor
+    // registryTokenEndpoint: "https://docker.beryju.org/service/token",
+    // registryService: "harbor-registry",
+};
+
+async function getToken(event) {
+    const fetch = await import('node-fetch');
+    const querystring = await import('querystring');
+    let scope = event.queryStringParameters["scope"];
+    let tokenParams = {
+        service: config.registryService,
+    };
+    delete event.headers.host;
+    let forwardHeaders = event.headers;
+    if (scope && scope.includes(":")) {
+        const repo = scope.split(":")[1];
+        console.debug(`oci-proxy[token]: original scope: ${scope}`);
+        scope = `repository:${config.namespace}${repo}:pull`;
+        console.debug(`oci-proxy[token]: rewritten scope: ${scope}`);
+        tokenParams["scope"] = scope;
+        // We only need to forward headers for authentication requests
+        forwardHeaders = {};
+    } else {
+        console.debug(`oci-proxy[token]: no scope`);
+        // For non-scoped requests, we need to forward some URL parameters
+        ["account", "client_id", "offline_token", "token"].forEach(param => {
+            tokenParams[param] = event.queryStringParameters[param]
+        });
+    }
+    const tokenUrl = `${config.registryTokenEndpoint}?${querystring.stringify(tokenParams)}`
+    console.debug(`oci-proxy[token]: final URL to fetch: ${tokenUrl}`)
+    const tokenRes = await fetch.default(tokenUrl, {
+        headers: forwardHeaders,
+    });
+    const tokenResult = await tokenRes.text();
+    console.debug(`oci-proxy[token]: Status ${tokenRes.status} body '${tokenResult}'`)
+    return {
+        statusCode: tokenRes.status,
+        body: tokenResult,
+    };
+}
+
+exports.handler = async function (event, context) {
+    console.debug(`oci-proxy: URL ${event.httpMethod} ${event.rawUrl}`);
+    if (event.queryStringParameters.hasOwnProperty("token")) {
+        console.debug("oci-proxy: handler=token proxy");
+        return await getToken(event);
+    }
+    if (event.headers.authorization && event.headers.authorization.startsWith("Bearer ")) {
+        console.debug("oci-proxy: authenticated root handler, returning 200");
+        return {
+            statusCode: 200,
+            headers: {
+                "Docker-Distribution-API-Version": "registry/2.0",
+                "content-type": "application/json",
+            },
+            body: JSON.stringify({}),
+        }
+    }
+    console.debug("oci-proxy: root handler, returning 401 with www-authenticate");
+    return {
+        statusCode: 401,
+        headers: {
+            "www-authenticate": `Bearer realm="https://${event.headers.host}/v2?token",service="${event.headers.host}",scope="repository:user/image:pull"`,
+            "Docker-Distribution-API-Version": "registry/2.0",
+            "content-type": "application/json",
+        },
+        body: JSON.stringify({}),
+    };
+}