convert "top2" to "top1" for host url

lib/fly_postgres.ex

@@ -32,7 +32,7 @@ defmodule Fly.Postgres do
   end
 
   @doc """
-  Rewrite the `:url` value to include DNS helpers of "top2.nearest.of" to find
+  Rewrite the `:url` value to include DNS helpers of "top1.nearest.of" to find
   the closes database to target. If the host already contains that, leave it
   unchanged. If it is missing, add it and return the updated the url in the
   config.
@@ -42,13 +42,20 @@ defmodule Fly.Postgres do
     uri = URI.parse(Keyword.get(config, :url))
 
     # if detected DNS helpers in the URI, return unchanged
-    if String.contains?(uri.host, ".nearest.of.") do
-      config
-    else
-      # Not detected. Add them to the Host and return new config with replaced
-      # host that includes DNS helpers
-      updated_uri = %URI{uri | host: "top2.nearest.of.#{uri.host}"} |> URI.to_string()
-      Keyword.put(config, :url, updated_uri)
+    cond do
+      String.contains?(uri.host, "top1.nearest.of.") ->
+        config
+
+      String.contains?(uri.host, "top2.nearest.of.") ->
+        new_host = String.replace(uri.host, "top2.nearest.of.", "top1.nearest.of.", global: false)
+        updated_uri = %URI{uri | host: new_host} |> URI.to_string()
+        Keyword.put(config, :url, updated_uri)
+
+      true ->
+        # Not detected. Add them to the Host and return new config with replaced
+        # host that includes DNS helpers
+        updated_uri = %URI{uri | host: "top1.nearest.of.#{uri.host}"} |> URI.to_string()
+        Keyword.put(config, :url, updated_uri)
     end
   end
 

test/fly_postgres_test.exs

@@ -4,7 +4,7 @@ defmodule Fly.PostgresTest do
 
   doctest Fly.Postgres
 
-  @url_dns "postgres://some-user:some-pass@top2.nearest.of.my-app-db.internal:5432/some_app"
+  @url_dns "postgres://some-user:some-pass@top1.nearest.of.my-app-db.internal:5432/some_app"
   @url_base "postgres://some-user:some-pass@my-app-db.internal:5432/some_app"
 
   setup do
@@ -24,13 +24,13 @@ defmodule Fly.PostgresTest do
       config = [stuff: "THINGS", url: @url_base]
       System.put_env([{"FLY_REGION", "xyz"}, {"DATABASE_URL", @url_base}])
       config = Fly.Postgres.rewrite_database_url(config)
-      assert Keyword.get(config, :url) |> String.contains?("top2.nearest.of.")
+      assert Keyword.get(config, :url) |> String.contains?("top1.nearest.of.")
     end
 
     test "changes port when not in primary region" do
       config = [stuff: "THINGS", url: System.get_env("DATABASE_URL")]
       # NOTE: Only the port number changed
-      expected = "postgres://some-user:some-pass@top2.nearest.of.my-app-db.internal:5433/some_app"
+      expected = "postgres://some-user:some-pass@top1.nearest.of.my-app-db.internal:5433/some_app"
       updated = Fly.Postgres.rewrite_database_url(config)
       assert expected == Keyword.get(updated, :url)
       # other things are altered
@@ -40,7 +40,7 @@ defmodule Fly.PostgresTest do
     test "changes port and adds DNS helpers if missing when not in primary region" do
       config = [stuff: "THINGS", url: @url_base]
       # NOTE: Port number changed and DNS parts added to host
-      expected = "postgres://some-user:some-pass@top2.nearest.of.my-app-db.internal:5433/some_app"
+      expected = "postgres://some-user:some-pass@top1.nearest.of.my-app-db.internal:5433/some_app"
       updated = Fly.Postgres.rewrite_database_url(config)
       assert Keyword.get(updated, :url) == expected
     end
@@ -49,15 +49,23 @@ defmodule Fly.PostgresTest do
   describe "rewrite_host/1" do
     test "adds dns helpers if missing from host" do
       config = [stuff: "THINGS", url: @url_base]
-      expected = "postgres://some-user:some-pass@top2.nearest.of.my-app-db.internal:5432/some_app"
+      expected = "postgres://some-user:some-pass@top1.nearest.of.my-app-db.internal:5432/some_app"
       updated = Fly.Postgres.rewrite_host(config)
       assert Keyword.get(updated, :url) == expected
     end
 
-    test "returns unmodified if dns helpers detected" do
-      config = [stuff: "THINGS", url: @url_dns]
+    test "returns unmodified if dns top1 helper detected" do
+      no_change = "postgres://some-user:some-pass@top1.nearest.of.my-app-db.internal:5432/some_app"
+      config = [stuff: "THINGS", url: no_change]
       updated = Fly.Postgres.rewrite_host(config)
-      assert Keyword.get(updated, :url) == @url_dns
+      assert Keyword.get(updated, :url) == no_change
+    end
+
+    test "changes to top1 if top2 is detected" do
+      config = [stuff: "THINGS", url: "postgres://some-user:some-pass@top2.nearest.of.my-app-db.internal:5432/some_app"]
+      expected = "postgres://some-user:some-pass@top1.nearest.of.my-app-db.internal:5432/some_app"
+      updated = Fly.Postgres.rewrite_host(config)
+      assert Keyword.get(updated, :url) == expected
     end
   end
 
@@ -77,7 +85,7 @@ defmodule Fly.PostgresTest do
       config = [stuff: "THINGS", url: @url_dns]
       updated = Fly.Postgres.rewrite_replica_port(config)
       # NOTE: Port number should change
-      expected = "postgres://some-user:some-pass@top2.nearest.of.my-app-db.internal:5433/some_app"
+      expected = "postgres://some-user:some-pass@top1.nearest.of.my-app-db.internal:5433/some_app"
       assert Keyword.get(updated, :url) == expected
       assert @url_dns != expected
     end
@@ -93,15 +101,15 @@ defmodule Fly.PostgresTest do
       System.put_env([{"FLY_REGION", "xyz"}])
       config = [stuff: "THINGS", url: @url_base]
       # NOTE: Only the port number changed
-      expected = "postgres://some-user:some-pass@top2.nearest.of.my-app-db.internal:5432/some_app"
+      expected = "postgres://some-user:some-pass@top1.nearest.of.my-app-db.internal:5432/some_app"
       {:ok, updated} = Fly.Postgres.config_repo_url(config)
       assert expected == Keyword.get(updated, :url)
     end
 
     test "update url for replica PORT when given" do
       config = [stuff: "THINGS", url: System.get_env("DATABASE_URL")]
       # NOTE: Only the port number changed
-      expected = "postgres://some-user:some-pass@top2.nearest.of.my-app-db.internal:5433/some_app"
+      expected = "postgres://some-user:some-pass@top1.nearest.of.my-app-db.internal:5433/some_app"
       {:ok, updated} = Fly.Postgres.config_repo_url(config)
       assert expected == Keyword.get(updated, :url)
     end