PR: Ping to Wake Heroku Dyno

[nelsonic]

Similar to dwyl/phoenix-content-negotiation-tutorial#5
This does not add any functionality, it's just to wake the Heroku Dyno
so the UX is better for the person reading the tutorial.
Review/merge after #35 👍

[nelsonic]

Well this is lame ...

On localhost I'm seeing:

20:44:20.728 [info]  Already up
...........................

  1) test GET /ping (GIF) renders 1x1 pixel (AppWeb.PingControllerTest)
     test/app_web/controllers/ping_controller_test.exs:5
     ** (CaseClauseError) no case clause matching: "ping"
     code: conn = get(conn, "/ping")
     stacktrace:
       (app 1.5.3) lib/app_web/views/item_view.ex:29: AppWeb.ItemView.filter/2
       (app 1.5.3) lib/app_web/templates/item/index.html.eex:17: AppWeb.ItemView."index.html"/1
       (phoenix 1.5.3) lib/phoenix/view.ex:310: Phoenix.View.render_within/3
       (phoenix 1.5.3) lib/phoenix/view.ex:472: Phoenix.View.render_to_iodata/3
       (phoenix 1.5.3) lib/phoenix/controller.ex:776: Phoenix.Controller.render_and_send/4
       (app 1.5.3) lib/app_web/controllers/item_controller.ex:1: AppWeb.ItemController.action/2
       (app 1.5.3) lib/app_web/controllers/item_controller.ex:1: AppWeb.ItemController.phoenix_controller_pipeline/2
       (phoenix 1.5.3) lib/phoenix/router.ex:352: Phoenix.Router.__call__/2
       (app 1.5.3) lib/app_web/endpoint.ex:1: AppWeb.Endpoint.plug_builder_call/2
       (app 1.5.3) lib/app_web/endpoint.ex:1: AppWeb.Endpoint.call/2
       (phoenix 1.5.3) lib/phoenix/test/conn_test.ex:225: Phoenix.ConnTest.dispatch/5
       test/app_web/controllers/ping_controller_test.exs:6: (test)



Finished in 0.5 seconds
28 tests, 1 failure

Randomized with seed 894831

When I run mix phx.routes I see it there:

ping_path  GET     /ping                                    AppWeb.PingController :ping

After running mix deps.clean --all followed by mix deps.get and then mix test
I see:

===> Compiling parse_trans
==> ping
Compiling 1 file (.ex)

== Compilation error in file lib/ping.ex ==
** (CompileError) lib/ping.ex:2: module Plug.Conn is not loaded and could not be found

could not compile dependency :ping, "mix compile" failed. You can recompile this dependency with "mix deps.compile ping", update it with "mix deps.update ping" or clean it with "mix deps.clean ping"

This is consistent with the error on Travis-CI:
https://travis-ci.com/github/dwyl/phoenix-todo-list-tutorial/builds/168870290#L335

So it seems we can't rely on the fact that Plug is included in Phoenix (which is a bummer!)
We have to make Plug an explicit dependency of ping for this to work.

[nelsonic]

This is working on: https://phoenix-content-negotiation.herokuapp.com/ping

(the 1x1 pixel is transparent, so it's not visible in this screenshot but it rendered)

[nelsonic]

Ok, I really don't understand this. It works on the other PR: dwyl/phoenix-content-negotiation-tutorial#5 which has virtually identical code.

[nelsonic]

Figured it out!
The /:filter route was taking precedence over the /ping route:

phoenix-todo-list-tutorial/lib/app_web/router.ex

Lines 23 to 26 in ab4a45b

	get "/:filter", ItemController, :index
	# see: https://github.com/dwyl/ping
	get "/ping", PingController, :ping

Moving the /ping route definition above the /:filter:

phoenix-todo-list-tutorial/lib/app_web/router.ex

Lines 15 to 23 in d4ed703

	# see: https://github.com/dwyl/ping
	get "/ping", PingController, :ping
	get "/", ItemController, :index
	resources "/items", ItemController
	get "/items/toggle/:id", ItemController, :toggle
	get "/clear", ItemController, :clear_completed
	# this route will "catch all" so has to be last:
	get "/:filter", ItemController, :index

Appears to work now. 👍

[codecov]

Codecov Report

Merging #39 into master will increase coverage by 8.16%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           master       #39      +/-   ##
===========================================
+ Coverage   91.83%   100.00%   +8.16%     
===========================================
  Files           5         6       +1     
  Lines          49        50       +1     
===========================================
+ Hits           45        50       +5     
+ Misses          4         0       -4     

Impacted Files	Coverage Δ
lib/app_web/controllers/ping_controller.ex	100.00% <100.00%> (ø)
lib/app_web/views/item_view.ex	100.00% <100.00%> (ø)
lib/app_web/controllers/item_controller.ex	100.00% <0.00%> (+13.33%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 3449bd1...61a2303. Read the comment docs.

[SimonLab]

🏓