steve-chavez

({ lib, newScope, stdenv, pkgs }: let

  # nicer aliases
  derive = stdenv.mkDerivation;
  concat = builtins.concatStringsSep " ";

  # vendored libuvc: don't build, just make sources available
  libuvc-src = derive {
    name = "libuvc-src";
    # using fetchgit instead fetchFromGitHub because

steve-chavez

There's no history in the database itself, if you're using psql you can use "\s" to see your command history there.

You can get future queries or other types of operations into the log files by setting log_statement in the postgresql.conf file. What you probably want instead is log_min_duration_statement, which if you set it to 0 will log all queries and their durations in the logs. That can be helpful once your apps goes live, if you set that to a higher value you'll only see the long running queries which can be helpful for optimization (you can run EXPLAIN ANALYZE on the queries you find there to figure out why they're slow).

Another handy thing to know in this area is that if you run psql and tell it "\timing", it will show how long every statement after that takes. So if you have a sql file that loo

steve-chavez

all: spi.so

spi.so: spi.o makefile
	g++ -shared -o spi.so spi.o
	cp --remove-destination spi.so /var/lib/postgresql/spi.so

spi.o: spi.cc makefile
	g++ -g -O2 -Wall -std=c++11 -fpic -c -o spi.o -I/usr/include/postgresql -I/usr/include/postgresql/9.4/server spi.cc

clean:

steve-chavez

-- from https://gist.github.com/ruslantalpa/b2f10eb1b5f6dd0fc1c154e071a1c91b

\set API_SCHEMA_NAME test

with tables as (
    -- Return a list of entities in the database (tables/views/materialized views)
    select
        n.nspname as table_schema,
        relname as table_name,
        case

steve-chavez

Scaling your API with rate limiters

The following are examples of the four types rate limiters discussed in the accompanying blog post. In the examples below I've used pseudocode-like Ruby, so if you're unfamiliar with Ruby you should be able to easily translate this approach to other languages. Complete examples in Ruby are also provided later in this gist.

In most cases you'll want all these examples to be classes, but I've used simple functions here to keep the code samples brief.

Request rate limiter

This uses a basic token bucket algorithm and relies on the fact that Redis scripts execute atomically. No other operations can run between fetching the count and writing the new count.

steve-chavez

Moved to git repository: https://github.com/denji/nginx-tuning

NGINX Tuning For Best Performance

For this configuration you can use web server you like, i decided, because i work mostly with it to use nginx.

Generally, properly configured nginx can handle up to 400K to 500K requests per second (clustered), most what i saw is 50K to 80K (non-clustered) requests per second and 30% CPU load, course, this was 2 x Intel Xeon with HyperThreading enabled, but it can work without problem on slower machines.

You must understand that this config is used in testing environment and not in production so you will need to find a way to implement most of those features best possible for your servers.

steve-chavez

let
  pkgs =
    let
      pinnedPkgs =
        builtins.fetchGit {
          name = "nixos-unstable-2019-12-05";
          url = https://github.com/nixos/nixpkgs/;
          rev = "cc6cf0a96a627e678ffc996a8f9d1416200d6c81";
        };
    in

steve-chavez

# Automatic nginx virtual subdomains with sub-folders or sub-directories
#
# Since the original source where I found this code is now offline, I have decided to mirror it here.
# All credit goes to: http://web.archive.org/web/20150307193208/http://www.messaliberty.com/2010/10/automatic-nginx-virtual-subdomains-with-sub-folders-or-sub-directories
#
# Description: In my web root directory I wanted create a folder called photos, and another called
# music using a sftp program. Without manually going back to the config file or to the shell I like to
# be able to access them at photos.nginxdomain.com and music.nginxdomain.com. That is what this config does.

# Redirect visitors from http://nginxdomain.com/ to http://www.nginxdomain.com/

steve-chavez

# Automatic nginx virtual subdomains with sub-folders or sub-directories
#
# Since the original source where I found this code is now offline, I have decided to mirror it here.
# All credit goes to: http://web.archive.org/web/20150307193208/http://www.messaliberty.com/2010/10/automatic-nginx-virtual-subdomains-with-sub-folders-or-sub-directories
#
# Description: In my web root directory I wanted create a folder called photos, and another called
# music using a sftp program. Without manually going back to the config file or to the shell I like to
# be able to access them at photos.nginxdomain.com and music.nginxdomain.com. That is what this config does.

# Redirect visitors from http://nginxdomain.com/ to http://www.nginxdomain.com/

steve-chavez

CREATE EXTENSION pgcrypto;
CREATE OR REPLACE FUNCTION totp(key BYTEA, clock_offset INT DEFAULT 0) RETURNS INT AS $$
DECLARE
    c BYTEA := '\x000000000' || TO_HEX(FLOOR(EXTRACT(EPOCH FROM NOW()) / 30)::INT + clock_offset);
    mac BYTEA := HMAC(c, key, 'sha1');
    trunc_offset INT := GET_BYTE(mac, 19) % 16;
    result INT := SUBSTRING(SET_BIT(SUBSTRING(mac FROM 1 + trunc_offset FOR 4), 7, 0)::TEXT, 2)::BIT(32)::INT % 1000000;
BEGIN
    RETURN result;
END;