Long Cheng kevinclcn

Benchmarking Nginx with Go

There are a lot of ways to serve a Go HTTP application. The best choices depend on each use case. Currently nginx looks to be the standard web server for every new project even though there are other great web servers as well. However, how much is the overhead of serving a Go application behind an nginx server? Do we need some nginx features (vhosts, load balancing, cache, etc) or can you serve directly from Go? If you need nginx, what is the fastest connection mechanism? This are the kind of questions I'm intended to answer here. The purpose of this benchmark is not to tell that Go is faster or slower than nginx. That would be stupid.

So, these are the different settings we are going to compare:

Go HTTP standalone (as the control group)
Nginx proxy to Go HTTP
Nginx fastcgi to Go TCP FastCGI
Nginx fastcgi to Go Unix Socket FastCGI

Kafka 0.11.0.0 (Confluent 3.3.0) added support to manipulate offsets for a consumer group via cli kafka-consumer-groups command.

List the topics to which the group is subscribed

kafka-consumer-groups --bootstrap-server <kafkahost:port> --group <group_id> --describe

Note the values under "CURRENT-OFFSET" and "LOG-END-OFFSET". "CURRENT-OFFSET" is the offset where this consumer group is currently at in each of the partitions.

Reset the consumer offset for a topic (preview)

Docker - How to cleanup (unused) resources

Once in a while, you may need to cleanup resources (containers, volumes, images, networks) ...

delete volumes

// see: https://github.com/chadoe/docker-cleanup-volumes

$ docker volume rm $(docker volume ls -qf dangling=true)

$ docker volume ls -qf dangling=true | xargs -r docker volume rm

Go vs. Scala (Akka) Concurrency

A comparison from 2 weeks using Go.

Actors vs. Functions

Akka's central principle is that there you have an ActorSystem which runs Actors. An Actor is defined as a class and it has a method to receive messages.

	vi /etc/environment

	add these lines...

	LANG=en_US.utf-8
	LC_ALL=en_US.utf-8

	package main

	import (
	"fmt"
	"log"
	"net"
	"time"
	)

	// Dialer .

	BenchmarkMutexCache/10-8 10000000 180 ns/op 0 B/op 0 allocs/op
	BenchmarkMutexCache/100-8 10000000 187 ns/op 0 B/op 0 allocs/op
	BenchmarkMutexCache/1000-8 10000000 214 ns/op 0 B/op 0 allocs/op
	BenchmarkMutexCache/10000-8 10000000 231 ns/op 0 B/op 0 allocs/op
	BenchmarkMutexCache/100000-8 5000000 254 ns/op 2 B/op 0 allocs/op
	BenchmarkMutexCache/1000000-8 1000000 1159 ns/op 102 B/op 1 allocs/op
	BenchmarkMutexCache/10000000-8 1000000 1481 ns/op 184 B/op 2 allocs/op
	BenchmarkMutexCache/100000000-8 1000000 1655 ns/op 187 B/op 3 allocs/op

	BenchmarkSyncMapCache/10-8 5000000 221 ns/op 0 B/op 0 allocs/op

	# from http://dzone.com/snippets/analyse-binary-log

	# cat /bin/mylog
	#!/bin/sh
	# usage:
	#$ mylog /mysql-bin-log/db-bin.000223
	# 2132 insert into customers
	# 1887 update userlog_access
	# 788 insert into gn_commission
	# 718 insert into con_tab

	# script used in consul
	# the following addition to sys is required:
	# https://gist.github.com/lefred/153448f7ea0341d6d0daa2738db6fcd8
	# v.0.1 - lefred 2018-02-14


	read -r mysql_primary mysql_readonly mysql_tx mysql_cert <<<$(mysql -h 127.0.0.1 -P 6446 -BNe "select * from sys.gr_member_routing_candidate_status")

	if [[ "${mysql_primary}" == "YES" ]] && [[ "${mysql_readonly}" == "NO" ]]
	then

	# script used in consul to check if mysql is primary master and asynchronous slave
	# v.0.1 - lefred 2018-02-16

	SLAVEOFDC="dc2"
	SLAVEUSER="async_repl"
	SLAVEPWD="asyncpwd"

	# check if we are the primary one
	ROLE=$(mysql -h 127.0.0.1 -BNe "select MEMBER_ROLE from performance_schema.replication_group_members where MEMBER_HOST=@@hostname")