feat(KNO-10406): add support for specifying a branch (#45)

Author: mattmikolay

README.md

@@ -49,6 +49,24 @@ Or you can pass it through when creating a client instance:
 knock_client = MyApp.Knock.client(api_key: "sk_12345")
 ```
 
+To use a branch, set the `branch` option in your configuration or client instance:
+
+```elixir
+config :my_app, MyApp.Knock,
+  api_key: "sk_12345"
+  branch: "my-feature-branch"
+
+# OR
+
+knock_client = MyApp.Knock.client(api_key: "sk_12345", branch: "my-feature-branch")
+```
+
+Alternatively, you can set it as an environment variable:
+
+```bash
+KNOCK_BRANCH="my-feature-branch"
+```
+
 ## Usage
 
 ### Identifying users

lib/knock.ex

@@ -49,13 +49,28 @@ defmodule Knock do
     json_client: JSX
   ```
 
-  You can read more about the availble adapters in the [Tesla documentation](https://hexdocs.pm/tesla/readme.html#adapters)
+  You can read more about the available adapters in the [Tesla documentation](https://hexdocs.pm/tesla/readme.html#adapters)
+
+  To use a branch, set the `branch` option in your configuration or client instance.
+
+  ```elixir
+  # config/runtime.exs
+
+  config :my_app, MyApp.KnockClient,
+    api_key: "sk_12345",
+    branch: "my-feature-branch"
+
+  # OR
+
+  knock_client = MyApp.Knock.client(api_key: "sk_12345", branch: "my-feature-branch")
+  ```
   """
 
   defmacro __using__(opts) do
     quote do
       @app_name Keyword.fetch!(unquote(opts), :otp_app)
       @api_key_env_var "KNOCK_API_KEY"
+      @branch_env_var "KNOCK_BRANCH"
 
       alias Knock.Client
 
@@ -72,6 +87,7 @@ defmodule Knock do
       defp fetch_options(overrides) do
         Application.get_env(@app_name, __MODULE__, [])
         |> maybe_resolve_api_key()
+        |> maybe_resolve_branch()
         |> Keyword.merge(overrides)
       end
 
@@ -82,6 +98,14 @@ defmodule Knock do
           _ -> Keyword.put(opts, :api_key, System.get_env(@api_key_env_var))
         end
       end
+
+      defp maybe_resolve_branch(opts) do
+        case Keyword.get(opts, :branch) do
+          branch when is_binary(branch) -> opts
+          {:system, var_name} -> Keyword.put(opts, :branch, System.get_env(var_name))
+          _ -> Keyword.put(opts, :branch, System.get_env(@branch_env_var))
+        end
+      end
     end
   end
 

lib/knock/api.ex

@@ -91,7 +91,9 @@ defmodule Knock.Api do
        [
          {"Authorization", "Bearer " <> config.api_key},
          {"User-Agent", "knocklabs/knock-elixir@#{library_version()}"}
-       ] ++ maybe_idempotency_key_header(Map.new(opts))}
+       ] ++
+         maybe_idempotency_key_header(Map.new(opts)) ++
+         maybe_branch_header(config)}
     ]
 
     Tesla.client(middleware, config.adapter)
@@ -101,4 +103,9 @@ defmodule Knock.Api do
     do: [{"Idempotency-Key", to_string(key)}]
 
   defp maybe_idempotency_key_header(_), do: []
+
+  defp maybe_branch_header(%{branch: branch}) when not is_nil(branch),
+    do: [{"X-Knock-Branch", to_string(branch)}]
+
+  defp maybe_branch_header(_), do: []
 end

lib/knock/client.ex

@@ -7,12 +7,16 @@ defmodule Knock.Client do
   ```elixir
   # Setup a client instance directly
   client = Knock.Client.new(api_key: "sk_test_12345")
+
+  # With optional branch
+  client = Knock.Client.new(api_key: "sk_test_12345", branch: "my-feature-branch")
   ```
   """
 
   @enforce_keys [:api_key]
   defstruct host: "https://api.knock.app",
             api_key: nil,
+            branch: nil,
             adapter: Tesla.Adapter.Hackney,
             json_client: Jason
 
@@ -22,6 +26,7 @@ defmodule Knock.Client do
   @type t :: %__MODULE__{
           host: String.t(),
           api_key: String.t(),
+          branch: String.t() | nil,
           adapter: atom(),
           json_client: atom()
         }
@@ -38,7 +43,7 @@ defmodule Knock.Client do
 
     opts =
       opts
-      |> Keyword.take([:host, :api_key, :adapter, :json_client])
+      |> Keyword.take([:host, :api_key, :branch, :adapter, :json_client])
       |> Map.new()
       |> maybe_set_adapter_default()
 

test/knock_test.exs

@@ -14,6 +14,14 @@ defmodule KnockTest do
       assert knock.adapter == Tesla.Adapter.Hackney
       assert knock.json_client == Jason
       assert knock.host == "https://api.knock.app"
+      assert knock.branch == nil
+    end
+
+    test "it allows configuring a branch" do
+      knock = TestClient.client(api_key: "sk_test_12345", branch: "my-feature-branch")
+
+      assert knock.api_key == "sk_test_12345"
+      assert knock.branch == "my-feature-branch"
     end
 
     test "it will default to reading the api key from env vars" do
@@ -24,7 +32,18 @@ defmodule KnockTest do
       assert knock.api_key == "sk_test_12345"
     end
 
-    test "it can read from application config" do
+    test "it will default to reading the branch from env vars" do
+      System.put_env("KNOCK_API_KEY", "sk_test_12345")
+      System.put_env("KNOCK_BRANCH", "test-branch")
+
+      knock = TestClient.client()
+
+      assert knock.branch == "test-branch"
+
+      System.delete_env("KNOCK_BRANCH")
+    end
+
+    test "it can read the api key from application config" do
       Application.put_env(:knock, KnockTest.TestClient,
         api_key: "sk_test_12345",
         foo: "bar"
@@ -35,6 +54,20 @@ defmodule KnockTest do
       assert knock.api_key == "sk_test_12345"
     end
 
+    test "it can read the branch from application config" do
+      Application.put_env(:knock, KnockTest.TestClient,
+        api_key: "sk_test_12345",
+        branch: "config-branch"
+      )
+
+      knock = TestClient.client()
+
+      assert knock.api_key == "sk_test_12345"
+      assert knock.branch == "config-branch"
+
+      Application.delete_env(:knock, KnockTest.TestClient)
+    end
+
     test "if set, will use the Tesla default adapter if one is not provided" do
       Application.put_env(:tesla, :adapter, Tesla.Adapter.Hackney)