Class: Presto::Client::StatementClient

Inherits:
Object
  • Object
show all
Defined in:
lib/presto/client/statement_client.rb

Constant Summary collapse

HEADERS = 
{
  "User-Agent" => "presto-ruby/#{VERSION}",
}
HTTP11_SEPARATOR = 
["(", ")", "<", ">", "@", ",", ";", ":", "\\", "<", ">", "/", "[", "]", "?", "=", "{", "}", " ", "\v"]
HTTP11_TOKEN_CHARSET = 
(32..126).map {|x| x.chr } - HTTP11_SEPARATOR
HTTP11_TOKEN_REGEXP = 
/^[#{Regexp.escape(HTTP11_TOKEN_CHARSET.join)}]+\z/
HTTP11_CTL_CHARSET = 
(0..31).map {|x| x.chr } + [127.chr]
HTTP11_CTL_CHARSET_REGEXP = 
/[#{Regexp.escape(HTTP11_CTL_CHARSET.join)}]/

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(faraday, query, options, next_uri = nil) ⇒ StatementClient

Returns a new instance of StatementClient.



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# File 'lib/presto/client/statement_client.rb', line 42

def initialize(faraday, query, options, next_uri=nil)
  @faraday = faraday
  @faraday.headers.merge!(HEADERS)

  @options = options
  @query = query
  @closed = false
  @exception = nil

  if model_version = @options[:model_version]
    @models = ModelVersions.const_get("V#{model_version.gsub(".", "_")}")
  else
    @models = Models
  end

  @faraday.headers.merge!(optional_headers)

  if next_uri
    body = faraday_get_with_retry(next_uri)
    @results = @models::QueryResults.decode(MultiJson.load(body))
  else
    post_query_request!
  end
end

Instance Attribute Details

#exception ⇒ Object (readonly)

Returns the value of attribute exception.



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# File 'lib/presto/client/statement_client.rb', line 132

def exception
  @exception
end

#query ⇒ Object (readonly)

Returns the value of attribute query.



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# File 'lib/presto/client/statement_client.rb', line 122

def query
  @query
end

Instance Method Details

#advance ⇒ Object 



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# File 'lib/presto/client/statement_client.rb', line 154

def advance
  if closed? || !has_next?
    return false
  end
  uri = @results.next_uri

  body = faraday_get_with_retry(uri)
  @results = load_json(uri, body, @models::QueryResults)

  return true
end

#cancel_leaf_stage ⇒ Object 



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# File 'lib/presto/client/statement_client.rb', line 222

def cancel_leaf_stage
  if uri = @results.next_uri
    response = @faraday.delete do |req|
      req.url uri
    end
    return response.status / 100 == 2
  end
  return false
end

#close ⇒ Object 



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# File 'lib/presto/client/statement_client.rb', line 253

def close
  return if @closed

  # cancel running statement
  # TODO make async reqeust and ignore response?
  cancel_leaf_stage

  @closed = true
  nil
end

#closed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/presto/client/statement_client.rb', line 128

def closed?
  @closed
end

#current_results ⇒ Object 



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# File 'lib/presto/client/statement_client.rb', line 146

def current_results
  @results
end

#debug? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/presto/client/statement_client.rb', line 124

def debug?
  !!@options[:debug]
end

#encode_properties(properties) ⇒ Object 



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# File 'lib/presto/client/statement_client.rb', line 238

def encode_properties(properties)
  # this is a hack to set same header multiple times.
  properties.map do |k, v|
    token = k.to_s
    field_value = v.to_s  # TODO LWS encoding is not implemented
    unless k =~ HTTP11_TOKEN_REGEXP
      raise Faraday::ClientError, "Key of properties can't include HTTP/1.1 control characters or separators (#{HTTP11_SEPARATOR.map {|c| c =~ /\s/ ? c.dump : c }.join(' ')})"
    end
    if field_value =~ HTTP11_CTL_CHARSET_REGEXP
      raise Faraday::ClientError, "Value of properties can't include HTTP/1.1 control characters"
    end
    "#{token}=#{field_value}"
  end.join("\r\n#{PrestoHeaders::PRESTO_SESSION}: ")
end

#exception? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/presto/client/statement_client.rb', line 134

def exception?
  @exception
end

#faraday_get_with_retry(uri, &block) ⇒ Object

Raises:



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# File 'lib/presto/client/statement_client.rb', line 187

def faraday_get_with_retry(uri, &block)
  start = Time.now
  attempts = 0

  begin
    begin
      response = @faraday.get(uri)
    rescue Faraday::Error::TimeoutError, Faraday::Error::ConnectionFailed
      # temporally error to retry
      response = nil
    rescue => e
      @exception = e
      raise @exception
    end

    if response
      if response.status == 200 && !response.body.to_s.empty?
        return response.body
      end

      if response.status != 503  # retry only if 503 Service Unavailable
        # deterministic error
        @exception = PrestoHttpError.new(response.status, "Presto API error at #{uri} returned #{response.status}: #{response.body}")
        raise @exception
      end
    end

    attempts += 1
    sleep attempts * 0.1
  end while (Time.now - start) < 2*60*60 && !@closed

  @exception = PrestoHttpError.new(408, "Presto API error due to timeout")
  raise @exception
end

#has_next? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/presto/client/statement_client.rb', line 150

def has_next?
  !!@results.next_uri
end

#query_failed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/presto/client/statement_client.rb', line 138

def query_failed?
  @results.error != nil
end

#query_info ⇒ Object 



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# File 'lib/presto/client/statement_client.rb', line 166

def query_info
  uri = "/v1/query/#{@results.id}"
  body = faraday_get_with_retry(uri)
  load_json(uri, body, @models::QueryInfo)
end

#query_succeeded? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/presto/client/statement_client.rb', line 142

def query_succeeded?
  @results.error == nil && !@exception && !@closed
end