r3code

Используем protobuff версии 3 https://developers.google.com/protocol-buffers/docs/proto3

Придерживаемся стиля https://developers.google.com/protocol-buffers/docs/style

Если вы удалили поля message определенные ранее, то для сохранения совместимости, их номера должны быть помечены как reserved, чтобы их нельзя было использовать повторно после.

Поддержка версионирования API - см. https://google.aip.dev/215

Переиспользуем готовые определения часто используемых типов (время, деньги, дата и др.) см. https://google.aip.dev/213

gkeep

background #e8e9ec
foreground #33374c

selection_background #d2d4dd
selection_foreground #33374c

cursor #33374c
cursor_text_color #e8e9ec

# white

max-rocket-internet

CPU: percentage of limit

A lot of people land when trying to find out how to calculate CPU usage metric correctly in prometheus, myself included! So I'll post what I eventually ended up using as I think it's still a little difficult trying to tie together all the snippets of info here and elsewhere.

This is specific to k8s and containers that have CPU limits set.

To show CPU usage as a percentage of the limit given to the container, this is the Prometheus query we used to create nice graphs in Grafana:

sum(rate(container_cpu_usage_seconds_total{name!~".*prometheus.*", image!="", container_name!="POD"}[5m])) by (pod_name, container_name) /

vasanthk

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

1. Clarify and agree on the scope of the system

• User cases (description of sequences of events that, taken together, lead to a system doing something useful)
  • Who is going to use it?
  • How are they going to use it?

ungoldman

How do you POST a JSON file with curl??

You can post a json file with curl like so:

curl -X POST -H "Content-Type: application/json" -d @FILENAME DESTINATION

so for example:

scaryguy

-- Firstly, remove PRIMARY KEY attribute of former PRIMARY KEY
ALTER TABLE <table_name> DROP CONSTRAINT <table_name>_pkey;

-- Then change column name of  your PRIMARY KEY and PRIMARY KEY candidates properly.
ALTER TABLE <table_name> RENAME COLUMN <primary_key_candidate> TO id;

jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

douglas

#!/bin/bash

# store the current dir
CUR_DIR=$(pwd)

# Let the person running the script know what's going on.
echo "\n\033[1mPulling in latest changes for all repositories...\033[0m\n"

# Find all git repositories and update it to the master latest revision
for i in $(find . -name ".git" | cut -c 3-); do