chore(electric): Clean up the response returned from /api/status (#412)

We should review the usage of connectors in the code base and refactor
those bits of code now that we have a single connector. In this PR I'm
only addressing the issue raised on Linear because it made sense to me
to make the Status API return a human-readable explanation of the
server's status.

components/electric/lib/electric/plug/status.ex

@@ -5,25 +5,20 @@ defmodule Electric.Plug.Status do
   use Plug.Router
   import Plug.Conn
 
-  plug(:match)
-  plug(:dispatch)
+  plug :match
+  plug :dispatch
 
   get "/" do
-    origins =
-      PostgresConnector.connectors()
-      |> Enum.map(fn origin ->
-        case PostgresConnectorMng.status(origin) do
-          :ready -> {origin, true}
-          :migration -> {origin, :migration}
-          _ -> {origin, false}
-        end
-      end)
+    [origin] = PostgresConnector.connectors()
 
-    data = %{
-      connectors: Map.new(origins)
-    }
+    msg =
+      if :ready == PostgresConnectorMng.status(origin) do
+        "Connection to Postgres is up!"
+      else
+        "Initializing connection to Postgres..."
+      end
 
-    send_resp(conn, 200, Jason.encode!(data))
+    send_resp(conn, 200, msg)
   end
 
   match _ do

components/electric/lib/electric/postgres/postgres_manager.ex

@@ -23,7 +23,7 @@ defmodule Electric.Replication.PostgresConnectorMng do
               subscription: String.t(),
               electric_connection: %{host: String.t(), port: pos_integer, dbname: String.t()}
             },
-            state: :reinit | :init | :subscribe | :ready | :migration
+            state: :init | :subscribe | :ready
           }
   end
 
@@ -44,9 +44,9 @@ defmodule Electric.Replication.PostgresConnectorMng do
     Electric.name(__MODULE__, origin)
   end
 
-  @spec status(Connectors.origin()) :: :init | :subscribe | :ready | :migration
+  @spec status(Connectors.origin()) :: :init | :subscribe | :ready
   def status(origin) do
-    GenServer.call(name(origin), {:status})
+    GenServer.call(name(origin), :status)
   end
 
   @impl GenServer
@@ -68,8 +68,7 @@ defmodule Electric.Replication.PostgresConnectorMng do
   end
 
   @impl GenServer
-  def handle_continue(init, %State{origin: origin} = state)
-      when init == :init or init == :reinit do
+  def handle_continue(:init, %State{origin: origin} = state) do
     case initialize_postgres(state) do
       {:ok, state1} ->
         :ok = PostgresConnector.start_children(state.config)
@@ -79,7 +78,7 @@ defmodule Electric.Replication.PostgresConnectorMng do
 
       error ->
         Logger.error("initialization for postgresql failed with reason: #{inspect(error)}")
-        {:noreply, schedule_retry(init, state)}
+        {:noreply, schedule_retry(:init, state)}
     end
   end
 
@@ -94,7 +93,7 @@ defmodule Electric.Replication.PostgresConnectorMng do
   end
 
   @impl GenServer
-  def handle_call({:status}, _from, state) do
+  def handle_call(:status, _from, state) do
     {:reply, state.state, state}
   end
 

e2e/tests/01.01_simple_startup.lux

@@ -5,7 +5,7 @@
 
 [newshell electric_curl]
     !curl http://localhost:5133/api/status
-    ?{"connectors":{"postgres_1":true}}
+    ??Connection to Postgres is up!
 
 [cleanup]
-    [invoke teardown]
+    [invoke teardown]

examples/beer-stars/README.md

@@ -92,7 +92,7 @@ Another service is an Electric sync service running replication on port `5133`:
 
 ```shell
 $ curl http://localhost:5133/api/status
-{"connectors":{"postgres_1":true}}
+Connection to Postgres is up!
 ```
 
 Finally, the app backend that talks to GitHub's GraphQL API runs on port `40001`: