ruby client sdk generation - host and base_path issues

Description

When generating a ruby client SDK from an OpenAPI V: 3.0.3 yaml api documentation, the swagger_client configuration.rb module (SwaggerClient) contains the Configuration class with the default variables host and base_path as follows:
@host = 'localhost'
@base_path = 'http://localhost:4010'

When executing any client app that uses any endpoint provided by the generated client the it fails to connect to the base_path (http://localhost:4010) the swagger client attempts to connect to the localhost port 80 instead, which ultimately fails. A mock server is running on port 4010

Swagger-codegen version

Swagger Codegen version: 3.0.24

Swagger declaration file content or url

Array of Server Objects which provide connectivity information to target servers.
Only using the localhost:4010

servers:
  - url: "http://localhost:4010"
  - url: "https://localhost:4433"

Command line used for generation

Generated the client SDK via the Swagger Editor

Steps to reproduce

irb(main):008:0> api_instance = SwaggerClient::TestApi.new
=> #<SwaggerClient::TestApi:0x00000000067f01b0 @api_client=#<SwaggerClient::ApiClient:0x00000000067f0188 @config=#<SwaggerClient::Configuration:0x0000000005e87b00 @scheme="http", @host="localhost", @base_path="http://localhost:4010", @api_key={"api-key"=>"dsfg-dsfg-sdfg-sdfg-45dfg-dfgdr44", "user-uid"=>"1234567"}, @api_key_prefix={}, @timeout=0, @client_side_validation=true, @verify_ssl=true, @verify_ssl_host=true, @params_encoding=nil, @cert_file=nil, @key_file=nil, @debugging=true, @inject_format=false, @force_ending_format=false, @logger=#<Logger:0x0000000005e879c0 @level=0, @progname=nil, @default_formatter=#<Logger::Formatter:0x0000000005e87970 @datetime_format=nil>, @formatter=nil, @logdev=#<Logger::LogDevice:0x0000000005e87920 @shift_period_suffix=nil, @shift_size=nil, @shift_age=nil, @filename=nil, @dev=#<IO:<STDOUT>>, @mon_mutex=#<Thread::Mutex:0x0000000005e878a8>, @mon_mutex_owner_object_id=49560720, @mon_owner=nil, @mon_count=0>>>, @user_agent="Swagger-Codegen/1.0.0/ruby", @default_headers={"Content-Type"=>"application/json", "User-Agent"=>"Swagger-Codegen/1.0.0/ruby"}>>
irb(main):009:0> begin
irb(main):010:1>   #Test connection to the API
irb(main):011:1>   result = api_instance.test_connection
irb(main):012:1>   p result
irb(main):013:1> rescue SwaggerClient::ApiError => e
irb(main):014:1>   puts "Exception when calling TestApi->test_connection: #{e}"
irb(main):015:1> end
D, [2021-02-03T11:29:33.843728 #4936] DEBUG -- : Calling API: TestApi.test_connection ...
  Trying 127.0.0.1:80...
  Trying ::1:80...
connect to 127.0.0.1 port 80 failed: Connection refused
connect to ::1 port 80 failed: Connection refused
Failed to connect to localhost port 80: Connection refused
Closing connection 0
D, [2021-02-03T11:29:37.098151 #4936] DEBUG -- : HTTP response body ~BEGIN~

~END~

Exception when calling TestApi->test_connection: Couldn't connect to server
HTTP status code: 0
=> nil

Related issues/PRs

Suggest a fix/enhancement

To rectify the problem the def initialize was modify as follows:

    def initialize
      @scheme = 'http'
      #@host = 'localhost'
      #@base_path = 'http://localhost:4010'
      @host = 'localhost:4010'
      @base_path = '/'       
      @api_key = {}
      @api_key_prefix = {}
      @timeout = 0
      @client_side_validation = true
      @verify_ssl = true
      @verify_ssl_host = true
      @params_encoding = nil
      @cert_file = nil
      @key_file = nil
      @debugging = false
      @inject_format = false
      @force_ending_format = false
      @logger = defined?(Rails) ? Rails.logger : Logger.new(STDOUT)

      yield(self) if block_given?
    End

After modifying these variables the client connects to the defined host (localhost) on the defined port (4010).
Here is the results after making the changes:

irb(main):023:0> begin
irb(main):024:1>   #Test connection to the API
irb(main):025:1>   result = api_instance.test_connection
irb(main):026:1>   p result
irb(main):027:1> rescue SwaggerClient::ApiError => e
irb(main):028:1>   puts "Exception when calling TestApi->test_connection: #{e}"
irb(main):029:1> end
D, [2021-02-03T12:03:14.694226 #18528] DEBUG -- : Calling API: TestApi.test_connection ...
  Trying 127.0.0.1:4010...
Connected to localhost (127.0.0.1) port 4010 (#0)
GET /api HTTP/1.1
Host: localhost:4010
User-Agent: Swagger-Codegen/1.0.0/ruby
Content-Type: application/json
Accept: application/json
api-key: f32516cc-57d3-43f5-9e16-8f86780a4cce
user-uid: 1647389405

Mark bundle as not supporting multiuse
HTTP/1.1 200 OK
Access-Control-Allow-Origin: *
Access-Control-Allow-Headers: *
Access-Control-Allow-Credentials: true
Access-Control-Expose-Headers: *
Content-type: application/json
Content-Length: 45
Date: Wed, 03 Feb 2021 18:03:14 GMT
Connection: keep-alive
Keep-Alive: timeout=5

Connection #0 to host localhost left intact
D, [2021-02-03T12:03:14.767184 #18528] DEBUG -- : HTTP response body ~BEGIN~
{"data":{"success":true},"meta":{"code":200}}
~END~

D, [2021-02-03T12:03:14.767752 #18528] DEBUG -- : API called: TestApi#test_connection
Data: #<SwaggerClient::Test:0x0000000006891c18 @meta={:code=>200}, @data={:success=>true}>
Status code: 200
Headers: {"Access-Control-Allow-Origin"=>"*", "Access-Control-Allow-Headers"=>"*", "Access-Control-Allow-Credentials"=>"true", "Access-Control-Expose-Headers"=>"*", "Content-type"=>"application/json", "Content-Length"=>"45", "Date"=>"Wed, 03 Feb 2021 18:03:14 GMT", "Connection"=>"keep-alive", "Keep-Alive"=>"timeout=5"}
#<SwaggerClient::Test:0x0000000006891c18 @meta={:code=>200}, @data={:success=>true}>
=> #<SwaggerClient::Test:0x0000000006891c18 @meta={:code=>200}, @data={:success=>true}>

Is there any miss configuration in the yaml that is causing the issue?

Start with the generated swagger_client configuration.rb and the TestApi#test_connection entry point. Reproduce generation from the shown OpenAPI 3.0.3 servers entry, then trace how the Ruby client assembles the request URL. Done means requests use localhost:4010 rather than port 80 without requiring manual edits to the generated configuration.