client.go

// Copyright (c) 2017 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

package kafkaclient

import (
	"os"

	"github.com/uber-go/kafka-client/kafka"
	"github.com/uber-go/tally"
	"go.uber.org/zap"
)

type (
	// Client refers to the kafka client. Serves as
	// the entry point to producing or consuming
	// messages from kafka
	Client interface {
		// NewConsumer returns a new instance of kafka consumer.
		NewConsumer(config *kafka.ConsumerConfig, consumerOpts ...ConsumerOption) (kafka.Consumer, error)
	}

	client struct {
		tally    tally.Scope
		logger   *zap.Logger
		resolver kafka.NameResolver
	}
)

// New returns a new kafka client.
func New(resolver kafka.NameResolver, logger *zap.Logger, scope tally.Scope) Client {
	return &client{
		resolver: resolver,
		logger:   logger,
		tally:    scope,
	}
}

// NewConsumer returns a new instance of kafka consumer.
//
// It is possible for NewConsumer to start a consumer which consumes from a subset of topics if EnablePartialConsumption,
// ConsumerOption is used.
// If partial consumption is enabled, error will not be returned.
func (c *client) NewConsumer(config *kafka.ConsumerConfig, consumerOpts ...ConsumerOption) (kafka.Consumer, error) {
	return newConsumerBuilder(config, c.resolver, c.tally, c.logger, consumerOpts...).build()
}

func clientID() string {
	name, err := os.Hostname()
	if err != nil {
		name = "unknown-kafka-client"
	}
	return name
}