add basic_auth config option

In favor of this `basic_auth_user` and `basic_auth_password` have been
removed.

Example:
```ruby
basic_auth: ->(topic) {
    username = ENV["TOPIC_#{topic.singularize.upcase}_USER"]
    password = ENV["SECRET_PASSWORD"]
    "#{username}:#{password}"
}
```
It should always return a string in the format `USERNAME:PASSWORD`. Instead
of using a proc this string can be set directly:
```ruby
basic_auth: "foo:bar"
```

Author: Crunch09

CHANGELOG.md

@@ -1,5 +1,22 @@
 # MagicPipe Changelog
 
+## Unreleased
+* Allow to set the `basic_auth` config as a proc which gets the topic name passed.
+Example:
+```ruby
+basic_auth: ->(topic) {
+    username = ENV["TOPIC_#{topic.singularize.upcase}_USER"]
+    password = ENV["SECRET_PASSWORD"]
+    "#{username}:#{password}"
+}
+```
+It should always return a string in the format `USERNAME:PASSWORD`. Instead
+of using a proc this string can be set directly:
+```ruby
+basic_auth: "foo:bar"
+```
+In favor of this `basic_auth_user` and `basic_auth_password` have been removed.
+
 ## v0.2.0
 
 Enhancing the HTTPS transport:

README.md

@@ -141,7 +141,7 @@ $magic_pipe = MagicPipe.build do |mp|
   }
   mp.https_transport_options = {
     url: "https://my.receiver.service/foo",
-    basic_auth_user: "bar",
+    basic_auth: "bar:foo",
   }
   mp.sqs_transport_options = {
     queue: "my_data_stream"
@@ -217,8 +217,7 @@ $magic_pipe = MagicPipe.build do |mp|
     url: "https://my.receiver.service/messages",
     dynamic_path_builder: -> (topic) { topic }
 
-    basic_auth_user: "foo",
-    basic_auth_password: "bar",
+    basic_auth: "foo:bar",
 
     timeout: 2,
     open_timeout: 3,

lib/magic_pipe/config.rb

@@ -74,8 +74,7 @@ def set_https_defaults
         #
         dynamic_path_builder: nil,
 
-        basic_auth_user: "missing",
-        basic_auth_password: "x",
+        basic_auth: "missing:x",
         timeout: 2,
         open_timeout: 3,
       }

lib/magic_pipe/transports/https.rb

@@ -21,6 +21,8 @@ def initialize(config, metrics)
       # So that it can be retried?
       #
       def submit(payload, metadata)
+        username, password = basic_auth(metadata[:topic])
+        @conn.basic_auth(username, password || "x")
         @conn.post do |r|
           path = dynamic_path(metadata[:topic])
           r.url(path) if path
@@ -45,12 +47,14 @@ def url
         @options.fetch(:url)
       end
 
-      def basic_auth_user
-        @options.fetch(:basic_auth_user)
-      end
-
-      def basic_auth_password
-        @options.fetch(:basic_auth_password)
+      def basic_auth(topic)
+        user_auth = @options.fetch(:basic_auth)
+        credentials = if user_auth.respond_to?(:call)
+          user_auth.call(topic)
+        else
+          user_auth
+        end
+        credentials.split(':')
       end
 
       def timeout
@@ -78,7 +82,6 @@ def user_agent
       def build_connection
         Faraday.new(url) do |f|
           f.request :retry, max: 2, interval: 0.1, backoff_factor: 2
-          f.request :basic_auth, basic_auth_user, basic_auth_password
 
           f.headers['Content-Type'] = content_type
           f.headers['User-Agent'] = user_agent

spec/magic_pipe/config_spec.rb

@@ -35,8 +35,7 @@
             actual = subject.https_transport_options
 
             expect(actual[:url]).to_not be_nil
-            expect(actual[:basic_auth_user]).to_not be_nil
-            expect(actual[:basic_auth_password]).to_not be_nil
+            expect(actual[:basic_auth]).to_not be_nil
             expect(actual[:timeout]).to_not be_nil
             expect(actual[:open_timeout]).to_not be_nil
 
@@ -59,8 +58,7 @@
             expect(actual[:url]).to eq "http://foo.bar"
             expect(actual[:dynamic_path_builder]).to eq fn
 
-            expect(actual[:basic_auth_user]).to_not be_nil
-            expect(actual[:basic_auth_password]).to_not be_nil
+            expect(actual[:basic_auth]).to_not be_nil
             expect(actual[:timeout]).to_not be_nil
             expect(actual[:open_timeout]).to_not be_nil
           end

spec/magic_pipe/transports/https_spec.rb

@@ -7,8 +7,7 @@
   let(:https_options) do
     {
       url: base_url,
-      basic_auth_user: basic_auth_user,
-      basic_auth_password: "x",
+      basic_auth: "#{basic_auth_user}:x",
     }
   end
 
@@ -108,5 +107,17 @@ def self.it_submits_a_request_with_the_correct_data
 
       it_submits_a_request_with_the_correct_data
     end
+
+    describe "when using a dynamic `basic_auth`" do
+      let(:target_url) { base_url }
+      let(:https_options) do
+        super().merge(
+          basic_auth: -> (topic) { "test-#{topic}:foobar" }
+        )
+      end
+      let(:auth_header) { "Basic " + Base64.strict_encode64("test-marsupials:foobar") }
+
+      it_submits_a_request_with_the_correct_data
+    end
   end
 end