Experimenting with Nginx worker_processes
February 14, 2019
0 comments Web development, Nginx, MacOSX, Linux
I have Nginx 1.15.8 installed with Homebrew on my macOS. By default the /usr/local/etc/nginx/nginx.conf
it set to...:
worker_processes 1;
But, from the documentation, it says:
"The optimal value depends on many factors including (but not limited to) the number of CPU cores, the number of hard disk drives that store data, and load pattern. When one is in doubt, setting it to the number of available CPU cores would be a good start (the value “auto” will try to autodetect it)." (bold emphasis mine)
What is the ideal number for me? The performance of Nginx on my laptop doesn't really matter. But for my side-projects it's important to have a fast Nginx since it serves static HTML and lots of static assets. However, on my personal servers I have a bunch of other resource hungry stuff going on that I know is more likely to need the resources, like Elasticsearch and uwsgi
.
To figure this out, I wrote a benchmark program that requested a small index.html
about 10,000 times across 10 concurrent clients with hey.
hey -n 10000 -c 10 http://peterbecom.local/plog/variable_cache_control/awspa
I ran this 10 times between changing the worker_processes
in the nginx.conf
file. Here's the output:
1 WORKER PROCESSES BEST : 13,607.24 reqs/s 2 WORKER PROCESSES BEST : 17,422.76 reqs/s 3 WORKER PROCESSES BEST : 18,886.60 reqs/s 4 WORKER PROCESSES BEST : 19,417.35 reqs/s 5 WORKER PROCESSES BEST : 19,094.18 reqs/s 6 WORKER PROCESSES BEST : 19,855.32 reqs/s 7 WORKER PROCESSES BEST : 19,824.86 reqs/s 8 WORKER PROCESSES BEST : 20,118.25 reqs/s
Or, as a graph:
Now note, this is done here on my MacBook Pro. Not on my Ubuntu DigitalOcean servers. For now, I just want to get a feeling for how these numbers correlate.
Conclusion
The benchmark isn't good enough. The numbers are pretty stable but I'm doing this on my laptop with multiple browsers idling, Slack, and Spotify running. Clearly, the throughput goes up a bit when you allocate more workers but if anything can be learned from this, start with going beyond 1 for a quick fix and from there start poking and more exhaustive benchmarks. And don't forget, if you have time to go deeper on this, to look at the combination of worker_connections
and worker_processes
.
How to encrypt a file with Emacs on macOS (ccrypt)
January 29, 2019
0 comments MacOSX, Linux
Suppose you have a cleartext file that you want to encrypt with a password, here's how you do that with ccrypt
on macOS. First:
▶ brew install ccrypt
Now, you have the ccrypt
program. Let's test it:
▶ cat secrets.txt
Garage pin: 123456
Favorite kid: bart
Wedding ring order no: 98c4de910X
▶ ccrypt secrets.txt
Enter encryption key: ▉▉▉▉▉▉▉▉▉▉▉
Enter encryption key: (repeat) ▉▉▉▉▉▉▉▉▉▉▉
# Note that the original 'secrets.txt' is replaced
# with the '.cpt' version.
▶ ls | grep secrets
secrets.txt.cpt
▶ less secrets.txt.cpt
"secrets.txt.cpt" may be a binary file. See it anyway?
There. Now you can back up that file on Dropbox or whatever and not have to worry about anybody being able to open it without your password. To read it again:
▶ ccrypt --decrypt --cat secrets.txt.cpt
Enter decryption key: ▉▉▉▉▉▉▉▉▉▉▉
Garage pin: 123456
Favorite kid: bart
Wedding ring order no: 98c4de910X
▶ ls | grep secrets
secrets.txt.cpt
Or, to edit it you can do these steps:
▶ ccrypt --decrypt secrets.txt.cpt
Enter decryption key: ▉▉▉▉▉▉▉▉▉▉▉
▶ vi secrets.txt
▶ ccrypt secrets.txt
Enter encryption key:
Enter encryption key: (repeat)
Clunky that you have you extract the file and remember to encrypt it back again. That's where you can use emacs
. Assuming you have emacs
already installed and you have a ~/.emacs
file. Add these lines to your ~/.emacs
:
(setq auto-mode-alist
(append '(("\\.cpt$" . sensitive-mode))
auto-mode-alist))
(add-hook 'sensitive-mode (lambda () (auto-save-mode nil)))
(setq load-path (cons "/usr/local/share/emacs/site-lisp/ccrypt" load-path))
(require 'ps-ccrypt "ps-ccrypt.el")
By the way, how did I know that the load path should be /usr/local/share/emacs/site-lisp/ccrypt
? I looked at the output from brew
:
▶ brew info ccrypt
ccrypt: stable 1.11 (bottled)
Encrypt and decrypt files and streams
...
==> Caveats
Emacs Lisp files have been installed to:
/usr/local/share/emacs/site-lisp/ccrypt
...
Anyway, now I can use emacs
to open the secrets.txt.cpt
file and it will automatically handle the password stuff:
This is really convenient. Now you can open an encrypted file, type in your password, and it will take care of encrypting it for you when you're done (saving the file).
Be warned! I'm not an expert at either emacs
or encryption so just be careful and if you get nervous take precaution and set aside more time to study this deeper.
elapsed function in bash to print how long things take
December 12, 2018
0 comments MacOSX, Linux
I needed this for a project and it has served me pretty well. Let's jump right into it:
# This is elapsed.sh
SECONDS=0
function elapsed()
{
local T=$SECONDS
local D=$((T/60/60/24))
local H=$((T/60/60%24))
local M=$((T/60%60))
local S=$((T%60))
(( $D > 0 )) && printf '%d days ' $D
(( $H > 0 )) && printf '%d hours ' $H
(( $M > 0 )) && printf '%d minutes ' $M
(( $D > 0 || $H > 0 || $M > 0 )) && printf 'and '
printf '%d seconds\n' $S
}
And here's how you use it:
# Assume elapsed.sh to be in the current working directory
source elapsed.sh
echo "Doing some stuff..."
# Imagine it does something slow that
# takes about 3 seconds to complete.
sleep 3
elapsed
echo "Some quick stuff..."
sleep 1
elapsed
echo "Doing some slow stuff..."
sleep 61
elapsed
The output of running that is:
Doing some stuff... 3 seconds Some quick stuff... 4 seconds Doing some slow stuff... 1 minutes and 5 seconds
Basically, if you have a bash script that does a bunch of slow things, it having a like of elapsed
there after some blocks of code will print out how long the script has been running.
It's not beautiful but it works.
hashin 0.14.0 with --update-all and a bunch of other features
November 13, 2018
0 comments Python, Linux
If you don't know it is, hashin
is a Python command line tool for updating your requirements file's packages and their hashes for use with pip install
. It takes the pain out of figuring out what hashes each package on PyPI has. It also takes the pain out of figuring out what version you can upgrade to.
In the 0.14.0 release (changelog) there are a bunch of new features. The most exciting one is --update-all
. Let's go through some of the new features:
Update all (--update-all
)
Suppose you want to bravely upgrade all the pinned packages to the latest and greatest. Before version 0.14.0 you'd have to manually open the requirements file and list every single package on the command line:
$ less requirements.txt
$ hashin Django requests Flask cryptography black nltk numpy
With --update-all
it's the same thing except it does that reading and copy-n-paste for you:
$ hashin --update-all
Particularly nifty is to combine this with --dry-run
if you get nervous about that many changes.
Interactive update all (--interactive
)
This new flag only makes sense when used together with --update-all
. Used together, it basically reads all packages in the requirements file, and for each one that there is a new version it asks you if you want to update it or skip it:
It looks like this:
$ hashin --update-all --interactive
PACKAGE YOUR VERSION NEW VERSION
Django 2.1.2 2.1.3 ✓
requests 2.20.0 2.20.1 ✘
numpy 1.15.2 1.15.4 ?
Update? [Y/n/a/q/?]:
You can also use the aliases hashin -u -i
to do the same thing.
Support for "extras"
If you want to have requests[security]
or markus[datadog]
in your requirements file, hashin used to not support that. This now works:
$ hashin "requests[security]"
Before, it would look for a package called verbatim requests[security]
on PyPI which obviously doesn't exist. Now, it parses that syntax, makes a lookup for requests
and when it's done it puts the extra syntax back into the requirements file.
Thanks Dustin Ingram for pushing for this one!
Atomic writes
Prior to this version, if you typed hashin requests flask numpy nltkay
it would go ahead and do one of those packages at a time and effectively open and edit the requirements file as many times as there are packages mentioned. The crux of that is that if you, for example, have a typo (e.g. nltkay
instead of nltk
) it would crash there and not roll back any of the other writes. It's not a huge harm but it certainly is counter intuitive.
Another place where this matters is with --dry-run
. If you specified something like hashin --dry-run requests flask numpy
you would get one diff per package and thus repeat the diff header 3 (excessive) times.
The other reason why atomic writes is important is if you use hashin --update-all --interactive
and it asks you if you want to update package1
, package2
, package3
, and then you decide "Nah. I don't want any of this. I quit!" it would just do that without updating the requirements file.
Better not-found errors
This was never a problem if you used Python 2.7 but for Python 3.x, if you typoed a package name you'd get a Python exception about the HTTP call and it wasn't obvious that the mistake lies with your input and not the network. Basically, it traps any HTTP errors and if it's 404
it's handled gracefully.
(Internal) Black everything and pytest everything
All source code is now formatted with Black which, albeit imperfect, kills any boring manual review of code style nits. And, it uses therapist
to wrap the black
checks and fixes.
And all unit tests are now written for pytest
. pytest
was already the tool used in TravisCI but now all of those self.assertEqual(foo, bar)
s have been replaced with assert foo == bar
.
The best grep tool in the world; ripgrep
June 19, 2018
3 comments Linux, Web development, MacOSX
tl;dr; ripgrep (aka. rg
) is the best tool to grep today.
ripgrep is a tool for searching files. Its killer feature is that it's fast. Like, really really fast. Faster than sift, git grep, ack, regular grep etc.
If you don't believe me, either read this detailed blog post from its author or just jump straight to the conclusion:
-
For both searching single files and huge directories of files, no other tool obviously stands above ripgrep in either performance or correctness.
-
ripgrep is the only tool with proper Unicode support that doesn’t make you pay dearly for it.
-
Tools that search many files at once are generally slower if they use memory maps, not faster.
I used to use git grep
whenever I was inside a git repo and sift
for everything else. That alone, was a huge step up from regular grep
. Granted, almost all my git repos are small enough that regular git grep
is faster than I can perceive many times. But with ripgrep
I can just add --no-ignore-vcs
and it searches in all the files mentioned in .gitignore
too. That's useful when you want to search in your own source as well as the files in node_modules
.
The installation instructions are easy. I installed it with brew install ripgrep
and the best way to learn how to use it is rg --help
. Remember that it has a lot of cool features that are well worth learning. It's written in Rust and so far I haven't had a single crash, ever. The ability to search by file type gets some getting used to (tip! use: rg --type-list
) and remember that you can pipe rg
output to another rg
. For example, to search for all lines that contain query
and string
you can use rg query | rg string
.
How to unset aliases set by Oh My Zsh
June 14, 2018
4 comments Linux, MacOSX
I use Oh My Zsh and I highly recommend it. However, it sets some aliases that I don't want. In particular, there's a plugin called git.plugin.zsh
(located in ~/.oh-my-zsh/plugins/git/git.plugin.zsh
) that interfers with a global binary I have in $PATH
. So when I start a shell the executable gg
becomes...:
▶ which gg
gg: aliased to git gui citool
That overrides /usr/local/bin/gg
which is the one I want to execute when I type gg
. To unset that I can run...:
▶ unset gg
▶ which gg
/usr/local/bin/gg
To override it "permanently", I added, to the end of ~/.zshrc
:
# This unsets ~/.oh-my-zsh/plugins/git/git.plugin.zsh
# So my /usr/local/bin/gg works instead
unalias gg
Now whenever I start a new terminal, it defaults to the gg
in /usr/local/bin/gg
instead.