huynhbaoan

A few show tricks to find slow queries in mongodb

Enable profiling

First, you have to enable profiling

> db.setProfilingLevel(1)

Now let it run for a while. It collects the slow queries ( > 100ms) into a capped collections, so queries go in and if it's full, old queries go out, so don't be surprised that it's a moving target...

huynhbaoan

#
# Config file for collectd(1).
# Please read collectd.conf(5) for a list of options.
# http://collectd.org/
#

##################
# Global settings
##################

huynhbaoan

#
# Acts as a nginx HTTPS proxy server
# enabling CORS only to domains matched by regex 
# /https?://.*\.mckinsey\.com(:[0-9]+)?)/
#
# Based on: 
# * http://blog.themillhousegroup.com/2013/05/nginx-as-cors-enabled-https-proxy.html
# * http://enable-cors.org/server_nginx.html
#
server {

huynhbaoan

acm.amazonaws.com
apigateway.amazonaws.com
athena.amazonaws.com
autoscaling.amazonaws.com
clouddirectory.amazonaws.com
cloudformation.amazonaws.com
cloudfront.amazonaws.com
cloudsearch.amazonaws.com
cloudtrail.amazonaws.com
codecommit.amazonaws.com

huynhbaoan

AWS S3 bucket and IAM policy recipes

• Anonymous GET access
• Anonymous GET access - match HTTP referrer
• Full access for specific IAM user/role
• GET/PUT/DELETE access to specific path within a bucket
• Restricted LIST & PUT/DELETE access to specific path within a bucket
• Full access (and S3 console) for specific IAM users
• Reference

Anonymous GET access

huynhbaoan

#!/bin/bash

set -u
set -e

set -o pipefail

export PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin

cat <<'EOF' > /etc/modprobe.d/blacklist-ipv6.conf

huynhbaoan

proxy_cache_path /tmp/cacheapi levels=1:2 keys_zone=microcacheapi:100m max_size=1g inactive=1d use_temp_path=off;
server {
    listen 443 ssl http2 default_server;
    listen [::]:443 ssl http2 default_server;
    server_name example.com;

    location /api/ {
        # Rate Limiting
        limit_req zone=reqlimit burst=20; # Max burst of request

huynhbaoan

Concept

• People talk about two servers: a web server (e.g. Nginx, Apache, etc.) and a app server (e.g. Language specific servers like Unicorn, Node.js, Tomcat, Http-Kit, etc.). There are exceptions where app servers not required at all (as web server itself provides preprocessors for handling), but let's not talk about now.
• Web servers are really fast and supports lot of standard and commonly used MIME-type requests. Concept of serving a file is -- forming and sending a response of bytes of data and labeling it with requested MIME-type by a client (e.g. web browser).
• Every response format (in layman's language, a file) is recognized by it's MIME-type, for e.g. a PNG image file has "image/png" MIME-type. JavaScript file has "text/javascript". HTML responses (or files) has "text/html". Plain text files have "text/plain".
• Modern Browsers supports a lot of standard MIME-types. Images, videos, text files (XML, HTML, SVG, JS), and they better know how to visualize it. Browser also knows unrec

huynhbaoan

###
### This gist contains 2 files : settings.json and lambda_function.py
###

### settings.json
{
    "extensions" : ["*.hdr", "*.glb", "*.wasm"]
}

### lambda_function.py