feat(#19): Manage exceptions by default and allow the gem's consumer …

…to manage them by itself

CHANGELOG.md

@@ -4,7 +4,7 @@ All changes to `grape-idempotency` will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [1.0.1] - (Next)
+## [1.1.0] - (Next)
 
 ### Fix
 
@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Feature
 
+* [#20](https://github.com/jcagarcia/grape-idempotency/pull/20): Manage `Redis` exceptions by default and allow the gem's consumer to manage them by itself - [@jcagarcia](https://github.com/jcagarcia).
 * Your contribution here.
 
 ## [1.0.0] - 2023-11-23

README.md

@@ -12,7 +12,8 @@ Topics covered in this README:
 - [Installation](#installation-)
 - [Basic Usage](#basic-usage-)
 - [How it works](#how-it-works-)
-- [Making idempotency key header mandatory](#making-idempotency-key-header-mandatory-)
+  - [Making idempotency key header mandatory](#making-idempotency-key-header-mandatory-)
+  - [Redis Storage Connectivity Issue](#redis-storage-connectivity-issue)
 - [Configuration](#configuration-)
 - [Changelog](#changelog)
 - [Contributing](#contributing)
@@ -81,7 +82,7 @@ Results are only saved if an API endpoint begins its execution. If incoming para
 
 Additionally, this gem automatically appends the `Original-Request` header and the `Idempotency-Key` header to your API's response, enabling you to trace back to the initial request that generated that specific response.
 
-## Making idempotency key header mandatory ⚠️
+### Making idempotency key header mandatory ⚠️
 
 For some endpoints, you want to enforce your consumers to provide idempotency key. So, when wrapping the code inside the `idempotent` method, you can mark it as `required`:
 
@@ -113,6 +114,14 @@ If the Idempotency-Key request header is missing for a idempotent operation requ
 
 If you want to change the error message returned in this scenario, check [How to configure idempotency key missing error message](#mandatory_header_response) section.
 
+### Redis Storage Connectivity Issue
+
+By default, the `grape-idempotency` gem is configured to handle potential `Redis` exceptions.
+
+Therefore, if an exception arises while attempting to read, write or delete data from the `Redis` storage, the gem will safeguard against a crash by returning empty results. Consequently, the associated `block` will execute without considering potential prior calls made with the provided idempotency key. As a result, the expected idempotent behavior will not be enforced.
+
+If you want to avoid this functionality, you have the option to configure the gem to refrain from handling these `Redis` exceptions. Please refer to the [manage_redis_exceptions](#manage_redis_exceptions) configuration property.
+
 ## Configuration 🪚
 
 In addition to the storage aspect, you have the option to supply additional configuration details to tailor the gem to the specific requirements of your project.
@@ -195,6 +204,44 @@ I, [2023-11-23T22:41:39.148523 #1]  DEBUG -- : [my-own-prefix] Request has been
 I, [2023-11-23T22:41:39.148537 #1]  DEBUG -- : [my-own-prefix] Returning the response from the original request.
 ```
 
+### manage_redis_exceptions
+
+By default, the `grape-idempotency` gem is configured to handle potential `Redis` exceptions.
+
+However, this approach carries a certain level of risk. In the case that `Redis` experiences an outage, the idempotent functionality will be lost, and this issue may go unnoticed.
+
+If you prefer to take control of handling potential `Redis` exceptions, you have the option to configure the gem to abstain from managing Redis exceptions.
+
+```ruby
+Grape::Idempotency.configure do |c|
+  c.storage = @storage
+  c.manage_redis_exceptions = false
+end
+```
+
+Now, if a `Redis` exception arises while attempting to utilize the `Redis` storage, the gem will re-raise the identical exception to your application. Thus, you will be responsible for handling it within your own code, such as:
+
+```ruby
+require 'grape'
+require 'grape-idempotency'
+
+class API < Grape::API
+    post '/payments' do
+      begin
+        idempotent do
+          status 201
+          Payment.create!({
+            amount: params[:amount]
+          })
+        end
+      rescue Redis::BaseError => e
+        error!("Redis error! Idempotency is very important here and we cannot continue.", 500)
+      end
+    end
+  end
+end
+```
+
 ### conflict_error_response
 
 When providing a `Idempotency-Key: <key>` header, this gem compares incoming parameters to those of the original request (if exists) and returns a `409 - Conflict` status code if they don't match, preventing accidental misuse. The response body returned by the gem looks like:

grape-idempotency.gemspec

@@ -22,7 +22,8 @@ Gem::Specification.new do |spec|
 
   spec.required_ruby_version = '>= 2.6'
 
-  spec.add_runtime_dependency 'grape', '~> 1'
+  spec.add_runtime_dependency 'grape', '>= 1'
+  spec.add_runtime_dependency 'redis', '>= 4'
 
   spec.add_development_dependency 'bundler'
   spec.add_development_dependency 'rspec'

lib/grape/idempotency.rb

@@ -1,4 +1,5 @@
 require 'grape'
+require 'redis'
 require 'logger'
 require 'securerandom'
 require 'grape/idempotency/version'
@@ -33,21 +34,21 @@ def idempotent(grape, required: false, &block)
         grape.error!(configuration.mandatory_header_response, 400) if required && !idempotency_key
         return block.call if !idempotency_key
 
-        cached_request = get_from_cache(idempotency_key)
-        log(:debug, "Request has been found for the provided idempotency key => #{cached_request}") if cached_request
-        if cached_request && (cached_request["params"] != grape.request.params || cached_request["path"] != grape.request.path)
-          log(:debug, "Request has conflicts. Same params? => #{cached_request["params"] != grape.request.params}. Same path? => #{cached_request["path"] != grape.request.path}")
+        stored_request = get_from_storage(idempotency_key)
+        log(:debug, "Request has been found for the provided idempotency key => #{stored_request}") if stored_request
+        if stored_request && (stored_request["params"] != grape.request.params || stored_request["path"] != grape.request.path)
+          log(:debug, "Request has conflicts. Same params? => #{stored_request["params"] != grape.request.params}. Same path? => #{stored_request["path"] != grape.request.path}")
           log(:debug, "Returning conflict error response.")
           grape.error!(configuration.conflict_error_response, 422)
-        elsif cached_request && cached_request["processing"] == true
+        elsif stored_request && stored_request["processing"] == true
           log(:debug, "Returning processing error response.")
           grape.error!(configuration.processing_response, 409)
-        elsif cached_request
+        elsif stored_request
           log(:debug, "Returning the response from the original request.")
-          grape.status cached_request["status"]
-          grape.header(ORIGINAL_REQUEST_HEADER, cached_request["original_request"])
+          grape.status stored_request["status"]
+          grape.header(ORIGINAL_REQUEST_HEADER, stored_request["original_request"])
           grape.header(configuration.idempotency_key_header, idempotency_key)
-          return cached_request["response"]
+          return stored_request["response"]
         end
 
         log(:debug, "Previous request information has NOT been found for the provided idempotency key.")
@@ -76,26 +77,32 @@ def idempotent(grape, required: false, &block)
 
         grape.header(ORIGINAL_REQUEST_HEADER, original_request_id)
         grape.body response
+      rescue Redis::BaseError => e
+        raise
       rescue => e
         log(:debug, "An unexpected error was raised when performing the block.")
-        if !cached_request && !response
+        if !stored_request && !response
           validate_config!
           log(:debug, "Storing error response.")
           original_request_id = get_request_id(grape.request.headers)
           stored_key = store_error_request(idempotency_key, grape.request.path, grape.request.params, grape.status, original_request_id, e)
-          log(:debug, "Error response stored.")
-          grape.header(ORIGINAL_REQUEST_HEADER, original_request_id)
-          grape.header(configuration.idempotency_key_header, stored_key)
+          if stored_key
+            log(:debug, "Error response stored.")
+            grape.header(ORIGINAL_REQUEST_HEADER, original_request_id)
+            grape.header(configuration.idempotency_key_header, stored_key)
+          end
         end
         log(:debug, "Re-raising the error.")
         raise
       ensure
-        if !cached_request && response
+        if !stored_request && response
           validate_config!
           log(:debug, "Storing response.")
           stored_key = store_request_response(idempotency_key, grape.request.path, grape.request.params, grape.status, original_request_id, response)
-          log(:debug, "Response stored.")
-          grape.header(configuration.idempotency_key_header, stored_key)
+          if stored_key
+            log(:debug, "Response stored.")
+            grape.header(configuration.idempotency_key_header, stored_key)
+          end
         end
       end
 
@@ -113,6 +120,10 @@ def update_error_with_rescue_from_result(error, status, response)
 
         store_request_response(idempotency_key, path, params, status, original_request_id, response)
         storage.del(stored_error[:error_key])
+      rescue Redis::BaseError => e
+        log(:error, "Storage error => #{e.message} - #{e}")
+        return if configuration.manage_redis_exceptions
+        raise
       end
 
       private
@@ -122,7 +133,10 @@ def validate_config!
       end
 
       def valid_storage?
-        configuration.storage && configuration.storage.respond_to?(:set)
+        configuration.storage &&
+        configuration.storage.respond_to?(:get) &&
+        configuration.storage.respond_to?(:set) &&
+        configuration.storage.respond_to?(:del)
       end
 
       def get_idempotency_key(headers)
@@ -141,11 +155,15 @@ def get_request_id(headers)
         request_id || "req_#{SecureRandom.hex}"
       end
 
-      def get_from_cache(idempotency_key)
+      def get_from_storage(idempotency_key)
         value = storage.get(key(idempotency_key))
         return unless value
 
         JSON.parse(value)
+      rescue Redis::BaseError => e
+        log(:error, "Storage error => #{e.message} - #{e}")
+        return if configuration.manage_redis_exceptions
+        raise
       end
 
       def store_processing_request(idempotency_key, path, params, request_id)
@@ -157,6 +175,9 @@ def store_processing_request(idempotency_key, path, params, request_id)
         }
 
         storage.set(key(idempotency_key), body.to_json, ex: configuration.expires_in, nx: true)
+      rescue Redis::BaseError => e
+        return true if configuration.manage_redis_exceptions
+        raise
       end
 
       def store_request_response(idempotency_key, path, params, status, request_id, response)
@@ -171,6 +192,10 @@ def store_request_response(idempotency_key, path, params, status, request_id, re
         storage.set(key(idempotency_key), body.to_json, ex: configuration.expires_in, nx: false)
 
         idempotency_key
+      rescue Redis::BaseError => e
+        log(:error, "Storage error => #{e.message} - #{e}")
+        return if configuration.manage_redis_exceptions
+        raise
       end
 
       def store_error_request(idempotency_key, path, params, status, request_id, error)
@@ -188,6 +213,10 @@ def store_error_request(idempotency_key, path, params, status, request_id, error
         storage.set(error_key(idempotency_key), body, ex: 30, nx: false)
 
         idempotency_key
+      rescue Redis::BaseError => e
+        log(:error, "Storage error => #{e.message} - #{e}")
+        return if configuration.manage_redis_exceptions
+        raise
       end
 
       def get_error_request_for(error)
@@ -207,6 +236,10 @@ def get_error_request_for(error)
             }
           end
         end.first
+      rescue Redis::BaseError => e
+        log(:error, "Storage error => #{e.message} - #{e}")
+        return if configuration.manage_redis_exceptions
+        raise
       end
 
       def is_an_error?(response)
@@ -252,7 +285,8 @@ def configuration
 
     class Configuration
       attr_accessor :storage, :logger, :logger_level, :logger_prefix, :expires_in, :idempotency_key_header,
-        :request_id_header, :conflict_error_response, :processing_response, :mandatory_header_response
+        :request_id_header, :conflict_error_response, :processing_response, :mandatory_header_response,
+        :manage_redis_exceptions
 
       class Error < StandardError; end
 
@@ -264,6 +298,7 @@ def initialize
         @expires_in = 216_000
         @idempotency_key_header = "idempotency-key"
         @request_id_header = "x-request-id"
+        @manage_redis_exceptions = true
         @conflict_error_response = {
           "title" => "Idempotency-Key is already used",
           "detail" => "This operation is idempotent and it requires correct usage of Idempotency Key. Idempotency Key MUST not be reused across different payloads of this operation."

lib/grape/idempotency/version.rb

@@ -2,6 +2,6 @@
 
 module Grape
   module Idempotency
-    VERSION = '1.0.1'
+    VERSION = '1.1.0'
   end
 end