Fixed unit tests on Logstash 8.x

Unit tests were failing due to a new requirement to include the `rackup`
gem. This commit includes the version of `rackup` prior to the Fiber based rework,
as that was causing test failures.

This commit also ensures that the request body is rewound before being read in tests.

Author: robbavey

CHANGELOG.md

@@ -1,3 +1,6 @@
+## 5.7.1
+  - Added new development `rackup` dependency to fix tests 
+
 ## 5.7.0
   - Added new `ssl_enabled` setting for enabling/disabling the SSL configurations [#144](https://github.com/logstash-plugins/logstash-output-http/pull/144)
 

logstash-output-http.gemspec

@@ -1,6 +1,6 @@
 Gem::Specification.new do |s|
   s.name            = 'logstash-output-http'
-  s.version         = '5.7.0'
+  s.version         = '5.7.1'
   s.licenses        = ['Apache License (2.0)']
   s.summary         = "Sends events to a generic HTTP or HTTPS endpoint"
   s.description     = "This gem is a Logstash plugin required to be installed on top of the Logstash core pipeline using $LS_HOME/bin/logstash-plugin install gemname. This gem is not a stand-alone program"
@@ -25,4 +25,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'logstash-devutils'
   s.add_development_dependency 'sinatra'
   s.add_development_dependency 'webrick'
+
+  # Pin to avoid using new Fiber-based implementation that breaks tests here
+  s.add_development_dependency 'rackup', "< 2.1.0"
 end

spec/outputs/http_spec.rb

@@ -255,7 +255,7 @@
       end
 
       let(:last_request) { TestApp.last_request }
-      let(:body) { last_request.body.read }
+      let(:body) {  read_last_request_body(last_request) }
       let(:content_type) { last_request.env["CONTENT_TYPE"] }
 
       it "should receive the request" do
@@ -458,7 +458,7 @@
   after  { subject.close }
 
   let(:last_request) { TestApp.last_request }
-  let(:last_request_body) { last_request.body.read }
+  let(:last_request_body) { read_last_request_body(last_request) }
 
   let(:event) { LogStash::Event.new("message" => "hello!") }
 
@@ -530,3 +530,10 @@
   end if tls_version_enabled_by_default?('TLSv1.3') && JOpenSSL::VERSION > '0.12' # due WEBrick uses OpenSSL
 
 end
+
+# Pre-emptively rewind the retrieval of `last_request.body` - for form based endpoints, the body
+# is placed in params, and body is empty, requiring a `rewind` for the body to be available for comparison
+def read_last_request_body(last_request)
+  last_request.body.rewind
+  last_request.body.read
+end