akoutmos · djthread · Dec 5, 2023 · Dec 5, 2023 · StandardMikeBenza · Dec 5, 2023
diff --git a/.gitignore b/.gitignore
@@ -30,3 +30,4 @@ erl_crash.dump
 # Ignore package tarball (built via "mix hex.build").
 prom_ex-*.tar
 
+/.elixir-tools
diff --git a/README.md b/README.md
@@ -64,7 +64,7 @@ Documentation can be found at [https://hexdocs.pm/prom_ex](https://hexdocs.pm/pr
 
 ## Supporting PromEx
 
-PromEx has an ambition goal: To provide Prometheus metrics and Grafana dashboards for as many of the libraries in the Elixir ecosystem as possible as well as a framework so that you can manage the lifecycle of your own metrics and dashboards.
+PromEx has an ambitious goal: To provide Prometheus metrics and Grafana dashboards for as many of the libraries in the Elixir ecosystem as possible as well as a framework so that you can manage the lifecycle of your own metrics and dashboards.
 
 If you rely on PromEx to monitor your production applications, it would much appreciated if you can give back to the
 project in order to help ensure its continued development.
@@ -93,7 +93,7 @@ project in order to help ensure its continued development.
 
 ## Setting Up PromEx
 
-The goal of PromEx is to have metrics set up be as simple and streamlined as possible. In that spirit, all
+The goal of PromEx is to make setting up metrics as simple and streamlined as possible. In that spirit, all
 that you need to do to start leveraging PromEx along with the built-in plugins is to run the following mix
 task (the `YOUR_PROMETHEUS_DATASOURCE_ID` value should align with what is configured in Grafana as the name of the
 Prometheus data source):

diff --git a/guides/howtos/Writing PromEx Plugins.md b/guides/howtos/Writing PromEx Plugins.md
@@ -22,7 +22,7 @@ provided to the struct `build` function.
 
 To have your custom plugin expose event based metrics, implement a `event_metrics/1` function and build out a collection
 of `Telemetry.Metrics` structs (`distribution`, `counter`, `last_value`, and `sum`). Be sure to look at plugins like
-`PromEx.Plugins.Phoenix` for more in depth examples.
+`PromEx.Plugins.Phoenix` for more in-depth examples.
 
 ```elixir
 defmodule MyApp.PromEx.Plugins.MyPhoenix do
@@ -61,7 +61,7 @@ end
 ## Adding Polling Metrics
 
 Polling metrics are similar to event metrics in that they require similar fields (`group_name` and `metrics` to be
-specific). In addition, the `PromEx.MetricTypes.Polling.build/4` function requires an `measurements_mfa` argument which
+specific). In addition, the `PromEx.MetricTypes.Polling.build/4` function requires a `measurements_mfa` argument which
 specifies what function will be executed on the polling interval. This function should run `:telemetry.execute/3`
 somewhere in its function body. Once that event is executed, the corresponding event in the struct will be triggered and
 you will capture the desired data point. The following example from `PromEx.Plugins.Beam` should highlight this concept:

diff --git a/lib/prom_ex/config.ex b/lib/prom_ex/config.ex
@@ -105,7 +105,7 @@ defmodule PromEx.Config do
       via the API.
 
     * `:auth_token` - The auth token that was created in Grafana so that PromEx can upload dashboards
-      via the API.
+      via the API. Alternatively, an MFA tuple is allowed. This function must return the auth token string.
 
     * `:upload_dashboards_on_start` - Using the config values that you set in your application config
       (`config.exs`, `dev.exs`, `prod.exs`, etc) PromEx will attempt to upload your Dashboards to
@@ -216,7 +216,8 @@ defmodule PromEx.Config do
       config value. When using `:basic` strategy you'll need to provide `:auth_user` and `:auth_password` values.
 
     * `:auth_token` - When using a `:bearer` authentication strategy, this field is required to validate the
-      incoming request against a valid auth token.
+      incoming request against a valid auth token. Alternatively, an MFA tuple is allowed. This function must
+      return the auth token string.
 
     * `:auth_user` - When using a `:basic` authentication strategy, this field is required to validate the
       incoming request against a valid user.

diff --git a/lib/prom_ex/grafana_client/connection.ex b/lib/prom_ex/grafana_client/connection.ex
@@ -24,6 +24,14 @@ defmodule PromEx.GrafanaClient.Connection do
     }
   end
 
+  def build(finch_process, %{host: host, auth_token: {m, f, a}}) do
+    %__MODULE__{
+      finch_process: finch_process,
+      base_url: normalize_host(host),
+      authorization: "Bearer #{apply(m, f, a)}"
+    }
+  end
+
   def build(finch_process, %{host: host, auth_token: auth_token}) do
     %__MODULE__{
       finch_process: finch_process,

diff --git a/lib/prom_ex/metrics_server/plug.ex b/lib/prom_ex/metrics_server/plug.ex
@@ -45,7 +45,7 @@ defmodule PromEx.MetricsServer.Plug do
         {:bearer, %{auth_token: auth_token, path: path} = plug_opts}
       ) do
     with ["Bearer " <> req_auth_token] <- get_req_header(conn, "authorization"),
-         true <- req_auth_token == auth_token do
+         true <- req_auth_token == resolve_auth_token(auth_token) do
       call(conn, {:none, plug_opts})
     else
       _ ->
@@ -78,4 +78,7 @@ defmodule PromEx.MetricsServer.Plug do
     |> put_resp_content_type("text/plain")
     |> send_resp(404, "Not Found")
   end
+
+  defp resolve_auth_token({m, f, a}), do: apply(m, f, a)
+  defp resolve_auth_token(token), do: token
 end
diff --git a/test/prom_ex/grafana_client/connection_test.exs b/test/prom_ex/grafana_client/connection_test.exs
@@ -3,6 +3,8 @@ defmodule PromEx.GrafanaClient.ConnectionTest do
 
   alias PromEx.GrafanaClient.Connection
 
+  def build_auth_token, do: "made_from_mfa"
+
   describe "build/1" do
     test "should properly build a connection struct with provided host, username, and password values" do
       finch_name = PromEx.TestFinchName
@@ -27,5 +29,17 @@ defmodule PromEx.GrafanaClient.ConnectionTest do
                authorization: "Bearer " <> ^auth_token
              } = Connection.build(finch_name, %{host: base_url, username: nil, password: nil, auth_token: auth_token})
     end
+
+    test "connection struct with MFA auth_token" do
+      finch_name = PromEx.TestFinchName
+      base_url = "http://localhost:3000"
+      auth_token = {__MODULE__, :build_auth_token, []}
+
+      assert %Connection{
+               finch_process: ^finch_name,
+               base_url: ^base_url,
+               authorization: "Bearer made_from_mfa"
+             } = Connection.build(finch_name, %{host: base_url, username: nil, password: nil, auth_token: auth_token})
+    end
   end
 end
diff --git a/test/prom_ex/metrics_server/plug_test.exs b/test/prom_ex/metrics_server/plug_test.exs
@@ -25,6 +25,8 @@ defmodule PromEx.MetricsServer.PlugTest do
     end
   end
 
+  def build_auth_token, do: "abcd"
+
   setup_all do
     System.put_env("GIT_SHA", "395459c")
     System.put_env("GIT_AUTHOR", "Alex")
@@ -119,6 +121,28 @@ defmodule PromEx.MetricsServer.PlugTest do
       assert response.resp_body =~ "Alex"
     end
 
+    test "should return the metrics for a PromEx instance if the bearer token is MFA" do
+      opts =
+        MetricsServer.Plug.init(%{
+          path: "/metrics",
+          prom_ex_module: DefaultPromExSetUp,
+          auth_strategy: :bearer,
+          auth_token: {__MODULE__, :build_auth_token, []}
+        })
+
+      conn =
+        :get
+        |> conn("/metrics")
+        |> put_req_header("authorization", "Bearer abcd")
+
+      response = MetricsServer.Plug.call(conn, opts)
+
+      assert response.status == 200
+      assert response.resp_body =~ "prom_ex_application_primary_info"
+      assert response.resp_body =~ "395459c"
+      assert response.resp_body =~ "Alex"
+    end
+
     test "should return a 401 if the request has an invalid bearer token" do
       opts =
         MetricsServer.Plug.init(%{
Original file line number	Diff line number	Diff line change
Expand Up		@@ -30,3 +30,4 @@ erl_crash.dump
		# Ignore package tarball (built via "mix hex.build").
		prom_ex-*.tar

		/.elixir-tools