Setup Action: Automatically fetch version based on Proxy version

actions/setup/README.md

@@ -26,6 +26,25 @@ Pre-requisites:
 
 Example usage:
 
+```yaml
+on:
+  workflow_dispatch: {}
+jobs:
+  demo-setup:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Install Teleport
+        uses: teleport-actions/setup@v1
+        with:
+          # specify version as "auto" and provide the address of your Teleport
+          # proxy using the "proxy" input.
+          version: auto
+          proxy: example.teleport.sh:443
+      - run: tsh # tsh, tbot and tctl will now be available
+```
+
+You can also specify a particular version of the Teleport binaries to install:
+
 ```yaml
 on:
   workflow_dispatch: {}

actions/setup/action.yml

@@ -3,7 +3,10 @@ description: 'Installs `teleport`, `tsh`, `tbot` and `tctl`.'
 inputs:
   version:
     required: true
-    description: 'Specify the Teleport version without the preceding "v"'
+    description: 'Specify the Teleport version without the preceding "v" or specify "auto" to use the version indicated by your Teleport cluster.'
+  proxy:
+    description: 'Specify the address of your Teleport Proxy, required if version is set to "auto".'
+    required: false
   enterprise:
     required: false
     default: 'false'

actions/setup/package.json

@@ -1,6 +1,6 @@
 {
   "name": "setup",
-  "version": "1.0.6",
+  "version": "1.1.0",
   "license": "Apache-2.0",
   "repository": "https://github.com/teleport-actions/setup.git",
   "scripts": {

actions/setup/src/index.ts

@@ -45,35 +45,67 @@ function versionString(
 interface Inputs {
   version: string;
   enterprise: boolean;
+  proxyAddr: string;
 }
 
 function getInputs(): Inputs {
   const version = core.getInput('version');
   if (version === '') {
     throw new Error("'version' input must be non-empty");
   }
-  if (version.startsWith('v')) {
-    throw new Error("'version' input should not be prefixed with 'v'");
-  }
-  const versionRegex =
-    /^([0-9]+)\.([0-9]+)\.([0-9]+)(?:-([0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*))?(?:\+[0-9A-Za-z-]+)?$/i;
-
-  if (!versionRegex.test(version)) {
-    throw new Error(
-      "incorrect 'version' specified, it should include all parts of the version e.g 11.0.1"
-    );
-  }
 
   const enterprise = core.getBooleanInput('enterprise');
+  const proxyAddr = core.getInput('proxy');
+
+  if (version !== 'auto') {
+    if (version.startsWith('v')) {
+      throw new Error("'version' input should not be prefixed with 'v'");
+    }
+    const versionRegex =
+      /^([0-9]+)\.([0-9]+)\.([0-9]+)(?:-([0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*))?(?:\+[0-9A-Za-z-]+)?$/i;
+
+    if (!versionRegex.test(version)) {
+      throw new Error(
+        "incorrect 'version' specified, it should include all parts of the version e.g 11.0.1 or be set to 'auto'"
+      );
+    }
+  } else {
+    if (proxyAddr === '') {
+      throw new Error(
+        "'proxy' input must be non-empty when 'version' is set to 'auto'"
+      );
+    }
+  }
 
   return {
     version,
     enterprise,
+    proxyAddr,
   };
 }
 
+async function fetchVersionFromProxy(proxyAddr: string): Promise<string> {
+  const resp = await fetch(`https://${proxyAddr}/webapi/find`);
+  const data = await resp.json();
+  const version = data?.auto_update?.tools_version;
+  if (!version) {
+    throw new Error(
+      `malformed response from proxy missing version: ${JSON.stringify(data)}`
+    );
+  }
+  return version;
+}
+
 async function run(): Promise<void> {
   const inputs = getInputs();
+
+  if (inputs.version === 'auto') {
+    core.info(`Fetching version from proxy: ${inputs.proxyAddr}`);
+    const proxyVersion = await fetchVersionFromProxy(inputs.proxyAddr);
+    core.info(`Fetched version: ${proxyVersion}`);
+    inputs.version = proxyVersion;
+  }
+
   const version = versionString(os.platform(), os.arch(), inputs.version);
   const toolName = inputs.enterprise ? 'teleport-ent' : 'teleport';
   core.info(`Installing ${toolName} ${version}`);