Merge pull request #42 from heroku/k80/fir-check

feat: add check for fir apps with error messages

Author: k80bowman

lib/exec.js

@@ -57,10 +57,9 @@ function * checkStatus(context, heroku, configVars) {
   });;
 }
 
-function * initFeature(context, heroku, callback) {
+function * initFeature(context, heroku, command = undefined, callback) {
   var buildpackUrls = ["https://github.com/heroku/exec-buildpack", "urn:buildpack:heroku/exec"]
   let promises = {
-    app: heroku.get(`/apps/${context.app}`),
     feature: heroku.get(`/apps/${context.app}/features/runtime-heroku-exec`),
     config: heroku.get(`/apps/${context.app}/config-vars`),
     buildpacks: heroku.request({
@@ -69,16 +68,30 @@ function * initFeature(context, heroku, callback) {
     })
   }
 
+  const app = yield heroku.get(`/apps/${context.app}`, {
+    headers: {
+      Accept:  'application/vnd.heroku+json; version=3.sdk'
+    }
+  })
+
+  if (app.generation === 'fir') {
+    const errorMessage = command === 'exec' ? 
+      'This command is unavailable for this app. Use `heroku run:inside` instead. See https://devcenter.heroku.com/articles/run-tasks-in-an-existing-dyno.' :
+      'This command is unavailable for this app.  See https://devcenter.heroku.com/articles/generations.'
+    cli.error(errorMessage)
+    cli.exit(1);
+  }
+
   let data = yield promises
   let feature = data.feature
   let configVars = data.config
   let buildpacks = data.buildpacks
 
-  if (data.app['space'] != null) {
-    if (data.app['space']['shield'] === true) {
+  if (app['space'] != null) {
+    if (app['space']['shield'] === true) {
       cli.error(`This feature is restricted for Shield Private Spaces`)
       cli.exit(1);
-    } else if (data.app['build_stack']['name'] === 'container') {
+    } else if (app['build_stack']['name'] === 'container') {
       cli.warn(`${context.app} is using the container stack which is not officially supported.`);
     } else if (buildpacks.length === 0) {
       cli.error(`${context.app} has no Buildpack URL set. You must deploy your application first!`)