add support for displaying prefix

commands/info.js

@@ -34,6 +34,10 @@ function formatInfo (info) {
     values: [`${topicCount} ${humanize.pluralize(topicCount, 'topic')}, see heroku kafka:topics`]
   })
 
+  if (cluster.topic_prefix) {
+    lines.push({ name: 'Prefix', values: [cluster.topic_prefix] })
+  }
+
   lines.push({
     name: 'Messages',
     values: [`${humanize.intComma(cluster.messages_in_per_sec)} ${humanize.pluralize(cluster.messages_in_per_sec, 'message')}/s`]

commands/prefix.js

@@ -0,0 +1,40 @@
+'use strict'
+
+let cli = require('heroku-cli-util')
+let co = require('co')
+let withCluster = require('../lib/clusters').withCluster
+let request = require('../lib/clusters').request
+
+const VERSION = 'v0'
+
+function * kafkaPrefix (context, heroku) {
+  yield withCluster(heroku, context.app, context.args.CLUSTER, function * (addon) {
+    let info = yield request(heroku, {
+      path: `/data/kafka/${VERSION}/clusters/${addon.id}`
+    })
+
+    if (info.topic_prefix) {
+      cli.log(info.topic_prefix)
+    } else {
+      cli.log('No prefix found.')
+    }
+  })
+}
+
+module.exports = {
+  topic: 'kafka',
+  command: 'prefix',
+  description: 'display user prefix',
+  help: `
+    Displays user prefix.
+
+    Examples:
+
+    $ heroku kafka:prefix
+    $ heroku kafka:prefix HEROKU_KAFKA_BROWN_URL
+`,
+  needsApp: true,
+  needsAuth: true,
+  args: [{name: 'CLUSTER', optional: true}],
+  run: cli.command({preauth: true}, co.wrap(kafkaPrefix))
+}

index.js

@@ -14,6 +14,7 @@ exports.commands = [
   require('./commands/consumer_groups_create.js'),
   require('./commands/consumer_groups_destroy.js'),
   require('./commands/fail.js'),
+  require('./commands/prefix.js'),
   require('./commands/upgrade.js'),
   require('./commands/info.js').info,
   require('./commands/info.js').root,

test/commands/prefix_test.js

@@ -0,0 +1,53 @@
+'use strict'
+
+const expect = require('chai').expect
+const mocha = require('mocha')
+const describe = mocha.describe
+const it = mocha.it
+const beforeEach = mocha.beforeEach
+const afterEach = mocha.afterEach
+const proxyquire = require('proxyquire')
+
+const cli = require('heroku-cli-util')
+const nock = require('nock')
+
+const withCluster = function * (heroku, app, cluster, callback) {
+  yield callback({ name: 'kafka-1', id: '00000000-0000-0000-0000-000000000000' })
+}
+
+const VERSION = 'v0'
+
+const cmd = proxyquire('../../commands/prefix', {
+  '../lib/clusters': {
+    withCluster
+  }
+})
+
+describe('kafka:prefix', () => {
+  let kafka
+
+  let consumerGroupsUrl = (cluster) => {
+    return `/data/kafka/${VERSION}/clusters/${cluster}`
+  }
+
+  beforeEach(() => {
+    kafka = nock('https://kafka-api.heroku.com:443')
+    cli.mockConsole()
+    cli.exit.mock()
+  })
+
+  afterEach(() => {
+    nock.cleanAll()
+    kafka.done()
+  })
+
+  it('displays a prefix', () => {
+    kafka.get(consumerGroupsUrl('00000000-0000-0000-0000-000000000000')).reply(200, {
+      attachment_name: 'HEROKU_KAFKA',
+      topic_prefix: 'nile-123.'
+    })
+
+    return cmd.run({app: 'myapp', args: {}})
+      .then(() => expect(cli.stdout).to.equal(`nile-123.\n`))
+  })
+})