A month or two ago, I decided to remove Varnish from my site and replace it with Nginx's built-in caching system. I was already using Nginx to proxy to my Python sites, so getting rid of Varnish meant one less thing to fiddle with. I spent a few days reading up on how to configure Nginx's cache and overhauling the various config files for my Python sites (yes, irony). In the course of my reading I bookmarked a number of interesting Nginx modules to return to, among them the Image Filter module.
I thought it would be neat to combine Nginx's reverse proxying, caching, and image filtering to create a thumbnailing server for my images hosted on S3. If you look closely at the
<img> tag below (and throughout this site), you can see Nginx in action.
walrus is my go-to toolkit for working with Redis in Python, and hopefully this post will convince you that it can be your go-to as well. I've tried to include lots of high-level Python APIs built on Redis primitives and the result is quite a lot of functionality. In this post I'll take you on a tour of the library and show examples of how it might be useful in your next project.
If you haven't heard, SQLite is an amazing database capable of doing real work in real production environments. In this post, I'll outline 5 reasons why I think you should use SQLite in 2016.
Sophia is a powerful key/value database with loads of features packed into a simple C API. In order to use this database in some upcoming projects I've got planned, I decided to write some Python bindings and the result is sophy. In this post, I'll describe the features of Sophia database, and then show example code using
sophy, the Python wrapper.
Here is an overview of the features of the Sophia database:
- Append-only MVCC database
- ACID transactions
- Consistent cursors
- Ordered key/value store
- Range searches
- Prefix searches
About three years ago I posted some instructions for building the Python SQLite driver for use with BerkeleyDB. While those instructions still work, they have the unfortunate consequence of stomping on any other SQLite builds you've installed in
/usr/local. I haven't been able to build
pysqlite with BerkeleyDB compiled in, because the source amalgamation generated by BerkeleyDB is invalid. So that leaves us with dynamically linking, and that requires that we use the BerkeleyDB
libsqlite, which is exactly what the previous post described.
In this post I'll describe a better approach. Instead of building a modified version of
libsqlite3, we'll modify
pysqlite to use the BerkeleyDB
The SQLite source tree is full of wonders. There is the the lemon parser generator, a btree implementation (well, kind of not surprising), multiple search engines, a json library, and more. It looks like Dr. Hipp is also experimenting with integrating the LSM key/value store from SQLite4 as a standalone virtual table.
I've written about the json and full-text search extensions, the lsm key/value store, and the transitive closure extension (useful when querying hierarchical data). In this post I'll be covering another interesting extension, the
spellfix1 extension (documentation).
One of the benefits of running an embedded database like SQLite is that you can configure SQLite to call into your application's code. SQLite provides APIs that allow you to create your own scalar functions, aggregate functions, collations, and even your own virtual tables. In this post I'll describe how I used the virtual table APIs to expose a nice API for creating table-valued (or, multi-value) functions in Python. The project is called
sqlite-vtfunc and is hosted on GitHub.
I've been working on some new features for Scout and thought they might be worth a short blog post. The super-short version is that Scout now supports complex filtering on metadata, adding another layer of filtering besides the full-text search. Additionally, I've added support for SQLite FTS5, using it by default if it's available otherwise falling back to FTS4.
I admit, I'm a little on edge right now. A book I co-authored on Flask is going to be published soon and I was sent a copy of the preface to approve. When I opened the preface, I was horrified. All my original work was gone and had been replaced by a bland, nonsensical paragraph written by someone I suspect was not a native English speaker.
Back in September, word started getting around trendy programming circles about a new file that had appeared in the SQLite fossil repo named json1.c. I originally wrote up a post that contained some gross hacks in order to get pysqlite to compile and work with the new
json1 extension. With the release of SQLite 3.9.0, those hacks are no longer necessary.
SQLite 3.9.0 is a fantastic release. In addition to the much anticipated
json1 extension, there is a new version of the full-text search extension called
fts5 improves performance of complex search queries and provides an out-of-the-box BM25 ranking implementation. You can also boost the significance of particular fields in the ranking. I suggest you check out the release notes for the full list of enhancements
This post will describe how to compile SQLite with support for
fts5. We'll use the new SQLite library to compile a python driver so we can use the new features from python. Because I really like
apsw, I've included instructions for building both of them. Finally, we'll use peewee ORM to run queries using the