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Extracting Tiles from PMTiles

There are a couple ways to extract map tiles from the various archives - the most popular being MBTiles and PMTiles these days. The best way, though, is using tile-join from felt/tippecanoe:

tile-join -e dir/ input.pmtiles

This will output all tiles as a hierarchy in dir - dir/{z}/{x}/{y}.{ext}. When working with vector tiles, you might need to specify -pC (no tile compression). By default, tiles are compressed in the archive, but if you need the raw tiles in a directory, specifying this option will output the raw, uncompressed files.

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IAM Policy for KMS-Encrypted Remote Terraform State in S3

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "s3:GetObject",
                "s3:PutObject",
                "s3:DeleteObject"
            ],
            "Resource": [
                "arn:aws:s3:::<bucket name>/*",
                "arn:aws:s3:::<bucket name>"
            ]
        },
        {
            "Effect": "Allow",
            "Action": [
                "kms:Encrypt",
                "kms:Decrypt",
                "kms:GenerateDataKey"
            ],
            "Resource": [
                "<arn of KMS key>"
            ]
        }
    ]
}

Don’t forget to update the KMS Key Policy, too. I spent a bit of time trying to figure out why it wasn’t working, until CloudTrail helpfully told me that the kms:GenerateDataKey permission was also required. Turn it on today, even if you don’t need the auditing. It’s an excellent permissions debugging tool.

Authenticating Linux logins via LDAP (Samba / Active Directory)

I’ve been working on infrastructure of a fleet of a few dozen Amazon EC2 instances for the past week, and with a rapidly-growing team, we decided it was appropriate to make a central authentication / authorization service.

So, that meant setting up some sort of LDAP server.

I was a bit intimidated at first (the most I’ve done is seen people manage and complain about Active Directory), but I finally got it set up. Here are the components:

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Upgrading PostgreSQL on Ubuntu

I recently started using Ubuntu Linux on my main development machine. That means that my PostgreSQL database is running under Ubuntu, as well. I’ve written guides to upgrading PostgreSQL using Homebrew in the past, but the upgrade process under Ubuntu was much smoother.

These steps are assuming that you use Ubuntu 16.04 LTS, and PostgreSQL 9.6 is already installed via apt.

  1. Stop the postgresql service.

    $ sudo service postgresql stop

  2. Move the newly-created PostgreSQL 9.6 cluster elsewhere.

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macOS Sierra

Here are the headline features of Sierra, and my thoughts about them.

Siri

Don’t use it on the phone, won’t use it on the Mac. It would be nice if I could use it by typing, though.

Universal Clipboard

This seems like a massive security risk. It works via iCloud, so if someone (like my daughter) is using my iPad, then it will sync the clipboard to that, too. How do I turn it off?

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Convox

I stumbled upon Convox a couple weeks ago, and found it pretty interesting. It’s led by a few people formerly from Heroku, and it certainly feels like it. A simple command-line interface to manage your applications on AWS, with almost no AWS-specific configuration required.

An example of how simple it is to deploy a new application:

$ cd ~/my-new-application
$ convox apps create
$ convox apps info
Name       my-new-application
Status     creating
Release    (none)
Processes  (none)
Endpoints
$ convox deploy
Deploying my-new-application
Creating tarball... OK
Uploading... 911 B / 911 B  100.00 % 0
RUNNING: tar xz
...
... wait 5-10 minutes for the ELB to be registered ...
$ convox apps info
Name       my-new-application
Status     running
Release    RIIDWNBBXKL
Processes  web
Endpoints  my-new-application-web-L7URZLD-XXXXXXX.ap-northeast-1.elb.amazonaws.com:80 (web)

Now, you can access your application at that ELB specified in the “Endpoints” section.

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A month with Linux on the Desktop

It’s been a bit over a month since I installed Linux as my main desktop OS on a PC I built to replace OS X on a (cylinder) Mac Pro. I installed Ubuntu MATE 16.04.

Here are my general thoughts:

  • Linux has come a far way in 6 years (last time I used it full-time on the desktop).

  • There are Linux versions of popular software that is vital to my workflows – Firefox, Chrome, Dropbox, Slack, Sublime Text, etc.

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Elixir anonymous function shorthand

Elixir’s Getting Started guides go over the &Module.function/arity and &(...) anonymous function shorthand, but there are a couple neat tricks that are not immediately apparent about this shorthand.

For example, you can do something like &"...".

iex> hello_fun = &"Hello, #{&1}"
iex> hello_fun.("Keita")
"Hello, Keita"

Let’s have some more fun.

iex> fun = &~r/hello #{&1}/
iex> fun.("world")
~r/hello world/

iex> fun = &~w(hello #{&1})
iex> fun.("world")
["hello", "world"]
iex> fun.("world moon mars")
["hello", "world", "moon", "mars"]

iex> fun = &if(&1, do: "ok", else: "not ok")
iex> fun.(true)
"ok"
iex> fun.(false)
"not ok"

You can even use defmodule to create an anonymous function that defines a new module.

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Elixir: A year (and a few months) in

In the beginning of 2015, I wrote a blog post about how my then-current programming language of choice (Ruby) was showing itself to not be as future-proof as I would have liked it to be.

A lot has changed since then, but a lot has remained the same.

First: I have started a few open-source Elixir projects:

  • Exfile -- a file upload handling, persistence, and processing library. Extracted from an image upload service I’m working on (also in Elixir).
  • multistream-downloader -- a quick tool to monitor and download HTTP-based live streams.
  • runroller -- a redirect “unroller” API, see the blog post about it.

The initial push to get me in to Elixir was indeed its performance, but that’s not what kept me. At the same time, I also tried learning Go and more recently, Rust has caught my attention.

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tokyo.ex #1

I attended my first Elixir-related meetup yesterday, tokyo.ex #1.

(If the slides don’t work here, I have also uploaded them to YouTube.)

In my 5-minute lightning talk, I talked about the basics of using Exfile. Exfile is a file upload persistence and processing library for Elixir with integrations for Ecto and Phoenix.

Playing around with AWS Certificate Manager

I’m a big Let’s Encrypt fan. They provide free SSL certificates for your web servers so you can protect the traffic from prying eyes. In fact, the connection between your web browser and my blog server is made private thanks to Let’s Encrypt.

Using Let’s Encrypt requires some setup and automation on your part if you want to use it in the AWS cloud, but AWS recently launched something called the AWS Certificate Manager or “ACM”. ACM takes care of issuing, renewing, and provisioning certificates for you – which is great because uploading SSL certificates to CloudFront and Elastic Load Balancers is not the most fun thing to do. I would pay for this, but Amazon has decided to give it to everyone for free. :-)

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