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

http://code.haleby.se/2017/01/27/markdown-to-pdf-in-macosx/

安装pandoc，mactex和xelatex
命令行程序都在/Libarary/Tex/Root/bin/x86_64-darwin/下面，需要将pdflatex, xelatex, tlmgr链接到/user/local/bin下面
需要使用tlmgr安装titling, lastpage
需要提供一个导出pdf的latex模板，默认的模板不支持中文
调用命令生成pdf

pandoc --pdf-engine=xelatex --template=template accesstoken.md create.md customer.md customerevent.md list.md tag.md -o customer.pdf

	# 遍历一个数字范围， https://stackoverflow.com/questions/169511/how-do-i-iterate-over-a-range-of-numbers-defined-by-variables-in-bash
	for i in $(seq 1 $END); do echo $i; done

	# 枚举多台机器上的java堆栈
	for i in $(seq 204 231); do ssh 192.168.12.$i "ls -lh /opt/log/stash/customer/java_pid1.hprof"; done

	# 使用sed做替换
	gsed -i -e 's/\(FROM .alpine-openjdk8[^:]\)$/\1:8u221/g' //Dockerfile

	# 使用ruby处理json行, 并设定encoding

	vi /etc/environment

	add these lines...

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

	https://raw.githubusercontent.com/ashleymcnamara/gophers/master/7TH_BIRTHDAY.png
	https://raw.githubusercontent.com/ashleymcnamara/gophers/master/ASHLEY_STEVE.png
	https://raw.githubusercontent.com/ashleymcnamara/gophers/master/Azure_Bit_Gopher.png
	https://raw.githubusercontent.com/ashleymcnamara/gophers/master/Azure_Gophers.png
	https://raw.githubusercontent.com/ashleymcnamara/gophers/master/BATMAN_GOPHER.png
	https://raw.githubusercontent.com/ashleymcnamara/gophers/master/BELGIUM.png
	https://raw.githubusercontent.com/ashleymcnamara/gophers/master/BLUE_GLASSES_GOPHER.png
	https://raw.githubusercontent.com/ashleymcnamara/gophers/master/BLUE_GOPHER.png
	https://raw.githubusercontent.com/ashleymcnamara/gophers/master/BUFFALO_CASTS.png
	https://raw.githubusercontent.com/ashleymcnamara/gophers/master/Biker_Gopher.png

	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