From 399073f77b1db34f958a691aefad17d4b5b41b83 Mon Sep 17 00:00:00 2001
From: Jose Diaz-Gonzalez <email@josediazgonzalez.com>
Date: Wed, 28 Feb 2018 02:27:29 -0500
Subject: [PATCH] feat: add support for checking if an application exists

This is useful for creating review applications in CI/CD pipelines.
---
 docs/deployment/application-management.md | 15 +++++++++++++++
 plugins/apps/functions                    |  9 +++++++++
 plugins/apps/subcommands/exists           | 11 +++++++++++
 tests/unit/10_apps.bats                   | 19 +++++++++++++++++++
 4 files changed, 54 insertions(+)
 create mode 100755 plugins/apps/subcommands/exists

diff --git a/docs/deployment/application-management.md b/docs/deployment/application-management.md
index b1e809205..6caa19a58 100644
--- a/docs/deployment/application-management.md
+++ b/docs/deployment/application-management.md
@@ -6,6 +6,7 @@
 apps:clone <old-app> <new-app>                 # Clones an app
 apps:create <app>                              # Create a new app
 apps:destroy <app>                             # Permanently destroy an app
+apps:exists <app>                              # Checks if an app exists
 apps:list                                      # List your apps
 apps:rename <old-app> <new-app>                # Rename an app
 apps:report [<app>] [<flag>]                   # Display report about an app
@@ -40,6 +41,20 @@ node-js-app
 python-app
 ```
 
+### Checking if an application exists
+
+For CI/CD pipelines, it may be useful to see if an application exists before creating a "review" application for a specific branch. You can do so via the `apps:exists` command:
+
+```shell
+dokku apps:exists  node-js-app
+```
+
+```
+App does not exist
+```
+
+The `apps:exists` command will return non-zero if the application does not exist, and zero if it does.
+
 ### Manually creating an application
 
 A common pattern for deploying applications to Dokku is to configure an application before deploying it. You can do so via the `apps:create` command:
diff --git a/plugins/apps/functions b/plugins/apps/functions
index 815aa4d74..97eafdd00 100755
--- a/plugins/apps/functions
+++ b/plugins/apps/functions
@@ -49,3 +49,12 @@ apps_destroy() {
 
   plugn trigger post-delete "$APP" "$IMAGE_TAG"
 }
+
+apps_exists() {
+  declare desc="checks if an app exists"
+  declare APP="$1"
+  is_valid_app_name "$APP"
+
+  [[ -d "$DOKKU_ROOT/$APP" ]] || dokku_log_fail "App does not exist"
+  dokku_log_info1 "App already exists"
+}
diff --git a/plugins/apps/subcommands/exists b/plugins/apps/subcommands/exists
new file mode 100755
index 000000000..792590fa7
--- /dev/null
+++ b/plugins/apps/subcommands/exists
@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
+source "$PLUGIN_AVAILABLE_PATH/apps/functions"
+
+apps_exists_cmd() {
+  declare desc="checks if an app exists"
+  local cmd="apps:exists"
+  apps_exists "$2"
+}
+
+apps_exists_cmd "$@"
diff --git a/tests/unit/10_apps.bats b/tests/unit/10_apps.bats
index 4cc4db573..d0ff646f2 100644
--- a/tests/unit/10_apps.bats
+++ b/tests/unit/10_apps.bats
@@ -132,3 +132,22 @@ teardown () {
   echo "status: "$status
   assert_success
 }
+
+@test "(apps) apps:exists" {
+  run dokku apps:exists $TEST_APP
+  echo "output: "$output
+  echo "status: "$status
+  assert_failure
+
+  create_app
+  run dokku apps:exists $TEST_APP
+  echo "output: "$output
+  echo "status: "$status
+  assert_success
+
+  run bash -c "dokku --force apps:destroy $TEST_APP"
+  echo "output: "$output
+  echo "status: "$status
+  assert_success
+
+}
\ No newline at end of file