Class: ClickhouseRuby::Connection

Inherits:
Object
  • Object
show all
Defined in:
lib/clickhouse_ruby/connection.rb

Overview

Single HTTP connection wrapper for ClickHouse communication

Provides a thin wrapper around Net::HTTP with:

  • SSL/TLS with verification ON by default (security best practice)

  • Configurable timeouts

  • Keep-alive support

  • Health check via ping

Examples:

Creating a connection

connection = ClickhouseRuby::Connection.new(
  host: 'localhost',
  port: 8123,
  use_ssl: false
)
connection.ping  # => true

With SSL (verification enabled by default)

connection = ClickhouseRuby::Connection.new(
  host: 'clickhouse.example.com',
  port: 8443,
  use_ssl: true,
  ssl_verify: true,  # This is the default!
  ssl_ca_path: '/path/to/ca-bundle.crt'
)

Defined Under Namespace

Classes: DecompressedResponse

Constant Summary collapse

NETWORK_ERROR_MAPPING =

Error mapping for network issues to ClickhouseRuby exceptions Each entry maps an exception class to a lambda that creates the appropriate error

{
  OpenSSL::SSL::SSLError => lambda { |e, _conn|
    SSLError.new("SSL connection failed: #{e.message}", original_error: e)
  },
  Errno::ECONNREFUSED => lambda { |e, conn|
    ConnectionNotEstablished.new("Connection refused to #{conn.host}:#{conn.port}: #{e.message}", original_error: e)
  },
  Errno::EHOSTUNREACH => lambda { |e, conn|
    ConnectionNotEstablished.new("Host unreachable #{conn.host}:#{conn.port}: #{e.message}", original_error: e)
  },
  SocketError => lambda { |e, conn|
    ConnectionNotEstablished.new("Socket error to #{conn.host}:#{conn.port}: #{e.message}", original_error: e)
  },
  Net::OpenTimeout => lambda { |e, conn|
    ConnectionTimeout.new("Connection timeout to #{conn.host}:#{conn.port}", original_error: e)
  },
  Net::ReadTimeout => lambda { |e, _conn|
    ConnectionTimeout.new("Read timeout: #{e.message}", original_error: e)
  },
  Net::WriteTimeout => lambda { |e, _conn|
    ConnectionTimeout.new("Write timeout: #{e.message}", original_error: e)
  },
  Errno::ECONNRESET => lambda { |e, _conn|
    ConnectionError.new("Connection reset: #{e.message}", original_error: e)
  },
  Errno::EPIPE => lambda { |e, _conn|
    ConnectionError.new("Broken pipe: #{e.message}", original_error: e)
  },
  IOError => lambda { |e, _conn|
    ConnectionError.new("IO error: #{e.message}", original_error: e)
  },
}.freeze
NETWORK_ERRORS =

All exception classes that should be caught and mapped

NETWORK_ERROR_MAPPING.keys.freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(host:, port: 8123, database: "default", username: nil, password: nil, use_ssl: false, ssl_verify: true, ssl_ca_path: nil, connect_timeout: 10, read_timeout: 60, write_timeout: 60, compression: nil, compression_threshold: 1024) ⇒ Connection

Creates a new connection



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# File 'lib/clickhouse_ruby/connection.rb', line 110

def initialize(
  host:,
  port: 8123,
  database: "default",
  username: nil,
  password: nil,
  use_ssl: false,
  ssl_verify: true,
  ssl_ca_path: nil,
  connect_timeout: 10,
  read_timeout: 60,
  write_timeout: 60,
  compression: nil,
  compression_threshold: 1024
)
  @host = host
  @port = port
  @database = database
  @username = username
  @password = password
  @use_ssl = use_ssl
  @ssl_verify = ssl_verify
  @ssl_ca_path = ssl_ca_path
  @connect_timeout = connect_timeout
  @read_timeout = read_timeout
  @write_timeout = write_timeout
  @compression = compression
  @compression_threshold = compression_threshold

  @http = nil
  @connected = false
  @last_used_at = nil
  @mutex = Mutex.new
end

Instance Attribute Details

#connected ⇒ Boolean (readonly) Also known as: connected? 



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# File 'lib/clickhouse_ruby/connection.rb', line 89

def connected
  @connected
end

#database ⇒ String (readonly) 



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# File 'lib/clickhouse_ruby/connection.rb', line 80

def database
  @database
end

#host ⇒ String (readonly) 



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# File 'lib/clickhouse_ruby/connection.rb', line 74

def host
  @host
end

#last_used_at ⇒ Time? (readonly) 



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# File 'lib/clickhouse_ruby/connection.rb', line 93

def last_used_at
  @last_used_at
end

#port ⇒ Integer (readonly) 



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# File 'lib/clickhouse_ruby/connection.rb', line 77

def port
  @port
end

#use_ssl ⇒ Boolean (readonly) 



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# File 'lib/clickhouse_ruby/connection.rb', line 86

def use_ssl
  @use_ssl
end

#username ⇒ String? (readonly) 



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# File 'lib/clickhouse_ruby/connection.rb', line 83

def username
  @username
end

Instance Method Details

#connect ⇒ self

Establishes the HTTP connection

Raises:



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# File 'lib/clickhouse_ruby/connection.rb', line 150

def connect
  @mutex.synchronize do
    return self if @connected && @http&.started?

    with_error_handling do
      @http = build_http
      @http.start
      @connected = true
      @last_used_at = Time.now
    end
  end

  self
end

#disconnect ⇒ self

Closes the HTTP connection



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# File 'lib/clickhouse_ruby/connection.rb', line 168

def disconnect
  @mutex.synchronize do
    if @http&.started?
      begin
        @http.finish
      rescue StandardError
        nil
      end
    end
    @http = nil
    @connected = false
  end

  self
end

#get(path, headers = {}) ⇒ Net::HTTPResponse

Executes an HTTP GET request



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# File 'lib/clickhouse_ruby/connection.rb', line 231

def get(path, headers = {})
  ensure_connected

  request = Net::HTTP::Get.new(path)
  request["Accept"] = "application/json"
  request["User-Agent"] = "ClickhouseRuby/#{ClickhouseRuby::VERSION} Ruby/#{RUBY_VERSION}"

  request.basic_auth(@username, @password || "") if @username

  headers.each { |k, v| request[k] = v }

  execute_request(request)
end

#healthy? ⇒ Boolean

Returns whether the connection is healthy



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# File 'lib/clickhouse_ruby/connection.rb', line 260

def healthy?
  @connected && @http&.started?
end

#inspect ⇒ String

Returns a string representation of the connection



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# File 'lib/clickhouse_ruby/connection.rb', line 277

def inspect
  scheme = @use_ssl ? "https" : "http"
  status = @connected ? "connected" : "disconnected"
  "#<#{self.class.name} #{scheme}://#{@host}:#{@port} #{status}>"
end

#ping ⇒ Boolean

Checks if ClickHouse is reachable and responsive



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# File 'lib/clickhouse_ruby/connection.rb', line 248

def ping
  connect unless connected?

  response = get("/ping")
  response.code == "200" && response.body&.strip == "Ok."
rescue StandardError
  false
end

#post(path, body, headers = {}) ⇒ Net::HTTPResponse

Executes an HTTP POST request

Raises:



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# File 'lib/clickhouse_ruby/connection.rb', line 200

def post(path, body, headers = {})
  ensure_connected

  request = Net::HTTP::Post.new(path)

  # Set default headers
  request["Content-Type"] = "application/x-www-form-urlencoded"
  request["Accept"] = "application/json"
  request["User-Agent"] = "ClickhouseRuby/#{ClickhouseRuby::VERSION} Ruby/#{RUBY_VERSION}"

  # Add compression headers if enabled
  request["Accept-Encoding"] = "gzip" if @compression == "gzip"

  # Add authentication
  request.basic_auth(@username, @password || "") if @username

  # Merge custom headers
  headers.each { |k, v| request[k] = v }

  # Handle request body compression
  setup_body(request, body)

  response = execute_request(request)
  decompress_response(response)
end

#reconnect ⇒ self

Reconnects by closing and reopening the connection



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# File 'lib/clickhouse_ruby/connection.rb', line 187

def reconnect
  disconnect
  connect
end

#stale?(max_idle_seconds = 300) ⇒ Boolean

Returns whether the connection has been idle too long



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# File 'lib/clickhouse_ruby/connection.rb', line 268

def stale?(max_idle_seconds = 300)
  return true unless @last_used_at

  Time.now - @last_used_at > max_idle_seconds
end