From a12889cbe0f6e82b25271410af9413c45de6a190 Mon Sep 17 00:00:00 2001
From: Pericles Theodorou <periclestheo@gmail.com>
Date: Thu, 7 Mar 2024 11:38:20 +0200
Subject: [PATCH 1/2] Validate naming

---
 lib/prometheus_exporter/client.rb | 28 +++++++++++++++++++++++++++-
 test/client_test.rb               | 21 +++++++++++++++++++++
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/lib/prometheus_exporter/client.rb b/lib/prometheus_exporter/client.rb
index 2302bd4c..58b3dbc9 100644
--- a/lib/prometheus_exporter/client.rb
+++ b/lib/prometheus_exporter/client.rb
@@ -5,7 +5,9 @@
 
 module PrometheusExporter
   class Client
-    class RemoteMetric
+    NAMING_VALIDATION_REGEX = /^[a-zA-Z_][a-zA-Z0-9_]*$/
+
+   class RemoteMetric
       attr_reader :name, :type, :help
 
       def initialize(name:, help:, type:, client:, opts: nil)
@@ -128,6 +130,8 @@ def find_registered_metric(name, type: nil, help: nil)
     end
 
     def send_json(obj)
+      return false unless valid_naming?(obj)
+
       payload =
         if @custom_labels
           if obj[:custom_labels]
@@ -269,6 +273,28 @@ def wait_for_empty_queue_with_timeout(timeout_seconds)
         sleep(0.05)
       end
     end
+
+    def valid_naming?(obj)
+      if obj[:name]
+        return false unless obj[:name].match?(NAMING_VALIDATION_REGEX)
+      end
+
+      custom_label_names = []
+      if obj[:custom_labels]
+        custom_label_names.concat(obj[:custom_labels].keys)
+      end
+
+      if @custom_labels
+        custom_label_names.concat(@custom_labels.keys)
+      end
+
+      return true if custom_label_names.empty?
+
+      custom_label_names.all? { |name|
+        str = name.to_s
+        str.match?(NAMING_VALIDATION_REGEX) && !str.start_with?("__")
+      }
+    end
   end
 
   class LocalClient < Client
diff --git a/test/client_test.rb b/test/client_test.rb
index 55051140..763da55e 100644
--- a/test/client_test.rb
+++ b/test/client_test.rb
@@ -65,4 +65,25 @@ def test_overriding_logger
 
     assert_includes(logs.string, "dropping message cause queue is full")
   end
+
+  def test_invalid_naming
+    client = PrometheusExporter::Client.new(custom_labels: {"label" => 1})
+
+    refute_same(false, client.send_json({}))
+    refute_same(false, client.send_json({name: "valid_name"}))
+    refute_same(false, client.send_json({name: "__valid_name"}))
+    refute_same(false, client.send_json({name: "__valid_name_1"}))
+    refute_same(false, client.send_json({name: "__valid_name_1", custom_labels: {"valid_name" => "value"}}))
+    refute_same(false, client.send_json({name: "valid_name", custom_labels: {"_valid_name" => "value"}}))
+
+    assert_equal(false, client.send_json({name: "invalid-name"}))
+    assert_equal(false, client.send_json({name: "valid_name", custom_labels: {"__invalid_name" => "value"}}))
+    assert_equal(false, client.send_json({name: "valid_name", custom_labels: {"invalid-name" => "value"}}))
+
+    client.custom_labels = {"__invalid_name" => "value"}
+    assert_equal(false, client.send_json({}))
+
+    client.custom_labels = {"invalid-name" => "value"}
+    assert_equal(false, client.send_json({}))
+  end
 end

From fe16e355933776a90bc481bbd86624fd40d5729b Mon Sep 17 00:00:00 2001
From: Pericles Theodorou <periclestheo@gmail.com>
Date: Thu, 7 Mar 2024 12:00:38 +0200
Subject: [PATCH 2/2] Indentation

---
 lib/prometheus_exporter/client.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/prometheus_exporter/client.rb b/lib/prometheus_exporter/client.rb
index 58b3dbc9..fac774c9 100644
--- a/lib/prometheus_exporter/client.rb
+++ b/lib/prometheus_exporter/client.rb
@@ -7,7 +7,7 @@ module PrometheusExporter
   class Client
     NAMING_VALIDATION_REGEX = /^[a-zA-Z_][a-zA-Z0-9_]*$/
 
-   class RemoteMetric
+    class RemoteMetric
       attr_reader :name, :type, :help
 
       def initialize(name:, help:, type:, client:, opts: nil)