From 874053bda2a402710cb48bdaef6aa69e20cc8bd5 Mon Sep 17 00:00:00 2001
From: Dmytro Shteflyuk <kpumuk@kpumuk.info>
Date: Tue, 24 Sep 2024 14:39:52 -0400
Subject: [PATCH] Added support for custom SSL certificate

---
 lib/kamal/configuration/docs/proxy.yml     | 11 +++++++++++
 lib/kamal/configuration/proxy.rb           |  2 ++
 lib/kamal/configuration/validator/proxy.rb |  8 ++++++++
 test/commands/app_test.rb                  |  8 ++++++++
 test/configuration/proxy_test.rb           | 10 ++++++++++
 5 files changed, 39 insertions(+)

diff --git a/lib/kamal/configuration/docs/proxy.yml b/lib/kamal/configuration/docs/proxy.yml
index 76ec3e41d..977e9014b 100644
--- a/lib/kamal/configuration/docs/proxy.yml
+++ b/lib/kamal/configuration/docs/proxy.yml
@@ -49,6 +49,17 @@ proxy:
   # Defaults to `false`:
   ssl: true
 
+  # Custom SSL certificate
+  #
+  # In scenarios where Let's Encrypt is not an option, or you already have your own
+  # certificates from a different Certificate Authority, you can configure kamal-proxy
+  # to load the certificate and the corresponding private key from disk.
+  #
+  # The certificate must be in PEM format and contain the full chain. The private key
+  # must also be in PEM format.
+  ssl_certificate_path: /data/cert/foo.example.com/fullchain.pem
+  ssl_private_key_path: /data/cert/foo.example.com/privkey.pem
+
   # Response timeout
   #
   # How long to wait for requests to complete before timing out, defaults to 30 seconds:
diff --git a/lib/kamal/configuration/proxy.rb b/lib/kamal/configuration/proxy.rb
index 6232c3e03..cc7ed3be7 100644
--- a/lib/kamal/configuration/proxy.rb
+++ b/lib/kamal/configuration/proxy.rb
@@ -30,6 +30,8 @@ def deploy_options
     {
       host: hosts,
       tls: proxy_config["ssl"].presence,
+      "tls-certificate-path": proxy_config["ssl_certificate_path"],
+      "tls-private-key-path": proxy_config["ssl_private_key_path"],
       "deploy-timeout": seconds_duration(config.deploy_timeout),
       "drain-timeout": seconds_duration(config.drain_timeout),
       "health-check-interval": seconds_duration(proxy_config.dig("healthcheck", "interval")),
diff --git a/lib/kamal/configuration/validator/proxy.rb b/lib/kamal/configuration/validator/proxy.rb
index b9e11cd99..5eb91a7af 100644
--- a/lib/kamal/configuration/validator/proxy.rb
+++ b/lib/kamal/configuration/validator/proxy.rb
@@ -10,6 +10,14 @@ def validate!
       if (config.keys & [ "host", "hosts" ]).size > 1
         error "Specify one of 'host' or 'hosts', not both"
       end
+
+      if config["ssl_certificate_path"].present? && config["ssl_private_key_path"].blank?
+        error "Must set a private key path to use a custom SSL certificate"
+      end
+
+      if config["ssl_private_key_path"].present? && config["ssl_certificate_path"].blank?
+        error "Must set a certificate path to use a custom SSL private key"
+      end
     end
   end
 end
diff --git a/test/commands/app_test.rb b/test/commands/app_test.rb
index 0e5cad796..58986309b 100644
--- a/test/commands/app_test.rb
+++ b/test/commands/app_test.rb
@@ -143,6 +143,14 @@ class CommandsAppTest < ActiveSupport::TestCase
       new_command.deploy(target: "172.1.0.2").join(" ")
   end
 
+  test "deploy with custom SSL certificate" do
+    @config[:proxy] = { "ssl" => true, "host" => "example.com", "ssl_certificate_path" => "/path/to/cert.pem", "ssl_private_key_path" => "/path/to/key.pem" }
+
+    assert_equal \
+      "docker exec kamal-proxy kamal-proxy deploy app-web --target=\"172.1.0.2:80\" --host=\"example.com\" --tls --tls-certificate-path=\"/path/to/cert.pem\" --tls-private-key-path=\"/path/to/key.pem\" --deploy-timeout=\"30s\" --drain-timeout=\"30s\" --buffer-requests --buffer-responses --log-request-header=\"Cache-Control\" --log-request-header=\"Last-Modified\" --log-request-header=\"User-Agent\"",
+      new_command.deploy(target: "172.1.0.2").join(" ")
+  end
+
   test "remove" do
     assert_equal \
       "docker exec kamal-proxy kamal-proxy remove app-web",
diff --git a/test/configuration/proxy_test.rb b/test/configuration/proxy_test.rb
index 588e5a350..9ece1637c 100644
--- a/test/configuration/proxy_test.rb
+++ b/test/configuration/proxy_test.rb
@@ -38,6 +38,16 @@ class ConfigurationProxyTest < ActiveSupport::TestCase
     assert_not config.proxy.ssl?
   end
 
+  test "ssl with certificate path and no private key path" do
+    @deploy[:proxy] = { "ssl" => true, "ssl_certificate_path" => "/path/to/cert.pem" }
+    assert_raises(Kamal::ConfigurationError) { config.proxy.ssl? }
+  end
+
+  test "ssl with private key path and no certificate path" do
+    @deploy[:proxy] = { "ssl" => true, "ssl_private_key_path" => "/path/to/key.pem" }
+    assert_raises(Kamal::ConfigurationError) { config.proxy.ssl? }
+  end
+
   private
     def config
       Kamal::Configuration.new(@deploy)