Posts from 2026

Having had Copilot crash out the other day, while working on the linter for BlogMore, I decided to lean into Gemini CLI a little more and see how that got on.

When I first tried it out, a week back, I found it worked fairly well but could be rather slow at times. On the whole though, I found it easy enough to work with; the results weren't too bad, even if it could throw out some mildly annoying code at times.

Yesterday evening though, because of the failure of Copilot, I decided to go just with Gemini and work on the problem of speeding up BlogMore. This worked really well. I found that it followed instructions well¹ when given them, and also did a good job of applying what it was told, constantly, without needing to be told again. I actually found I had a bit of a flow going (in the minimal way that you can get any sort of flow going when you're not hand-coding).

Using it, I tackled all the main bottlenecks in BlogMore and got things working a lot faster (at this point it's generating a site in about 1/4 of the time it used to take). By the time that work was done, I wanted to do some last tidying up.

This was where it suddenly got unreliable. I asked it a simple question, not even tasking it with something to do, and it went into "Thinking..." mode and never came back out of it. I seem to remember I gave it 10 minutes and then cancelled the request.

After that I tried again with a different question, having quit the program and started it again with --resume. This time I asked it a different question and the same thing happened. I hit cancel again and then, a moment later, finally got an answer to the previous question.

From this point onwards I could barely ever get a reply out of it. I even tried quitting and starting up again without --resume, only for the same result.

A quick search turns up reports similar to this issue on Reddit, Google's support forums and on GitHub. It looks like I'm not alone in running into this.

This here is one of the things that concerns me about the idea of ever adopting agents as the primary tool for getting code written: the unreliability of their availability, and so the resulting inconsistency of the output. It feels like any perceived win in terms of getting the code written is going to be lost in the frustration of either waiting and trying again when it just gives up playing along, or in running from one agent to another, hoping you find the one that is capable of working with you at that given moment.

Meanwhile folk talk like it's the solution to the problem of software development. It's especially concerning when those folk are in "engineering leadership" or a position with a similar name. When they talk like this they are either displaying a lack of foresight, or betraying a lack of care for the craft they are supposed to represent (amongst other reasons).

It's very timely that this post from Rob Pike popped up in my feed this morning:

Although trained in physics, I worked in the computing industry with pride and purpose for over 40 years. And now I can do nothing but sit back and watch it destroy itself for no valid reason beyond hubris (if I'm being charitable).

Ineffable sadness watching something I once loved deliberately lose its soul.

Yup.

It has arrived!

I feel that Valve have upped their presentation game a little. Even the box feels quality; I don't remember my Steam Deck turning up in such a nice box.

I might give it a go tonight. I probably should. On the other hand there's some coding I want to mess with so I have competing desires!

The plan, at the moment, given my Windows gaming PC is still kind of packed up after moving late last year, is to pair this up with either the Deck, or perhaps even my MacBook (it's got Steam on it now too) and try out a couple of games and see how it feels.

As mentioned recently, Andy did a nifty bit of testing of BlogMore to measure the performance hit of each of the optional generation features. Performance is something I haven't really spent much time thinking about; I cared more about how the result looked than I did about how quickly a site got generated.

I seem to remember that, early on, I did have a bit of a play with trying to get Copilot to tackle the idea of parallel generation of parts of the site, but I didn't seem to get any sort of win out of it so I closed the PR and gave up on the idea.

Now though, especially having added the elapsed time of each step to the progress report during generation, I am curious about what wins there are. One that came to mind right away, and I have been considering dealing with for a wee while, is the fact that every generation downloads the FontAwesome metadata. Caching that would be a simple win, for example.

But, if I'm going to do this, it makes sense that I stick to the spirit of this project and get one or more agents to tackle the problem. So I asked Gemini CLI to look over the codebase and give me some big easy wins. I made clear I didn't want it to do any work yet, I just wanted it to report back what it could find.

The result made a lot of sense. Here's what it said:

Performance Optimization Recommendations for BlogMore¶

I have conducted a comprehensive review of the blogmore codebase and identified several areas where measurable and significant speedups can be achieved, particularly for larger sites.

1. Backlink Snippet Extraction (Highest Impact)¶

The most significant bottleneck is in src/blogmore/backlinks.py. The build_backlink_map function iterates through every internal link in every post. For each link, it calls _extract_snippet, which re-parses the entire Markdown content of the source post to generate a plain-text snippet.

• The Issue: If a post has 20 internal links, it is parsed 20 times just for backlinks.
• The Win: Modify the logic to insert unique markers for all links in a post and perform a single Markdown-to-plain-text conversion per post.

2. Redundant Markdown Parsing for Metadata¶

The Post object in src/blogmore/parser.py has properties like description and reading_time that are accessed frequently (on the post page, index pages, RSS feeds, search index, etc.).

• The Issue: Post.description calls extract_first_paragraph, and Post.reading_time calls calculate_reading_time. Both of these functions perform a full Markdown conversion every time they are called because they are not cached.
• The Win: Use functools.cached_property on these fields. Additionally, these should be calculated by extracting text from the html_content that has already been generated during the initial parse, rather than re-parsing the raw Markdown.

3. Sequential Processing¶

The generator currently processes everything sequentially in a single thread.

• The Issue: For a site with hundreds or thousands of posts, the initial Markdown parsing and the subsequent Jinja2 rendering are strictly serial, leaving multi-core CPUs mostly idle.
• The Win: Use multiprocessing (e.g., ProcessPoolExecutor) to parallelize the parsing of Markdown files and the rendering of HTML pages. Since these tasks are CPU-bound and independent, this would scale almost linearly with the number of CPU cores.

4. Asset Management Inefficiencies¶

The AssetManager in src/blogmore/generator/assets.py performs some operations that could be optimized:

• FontAwesome Metadata: It downloads icon metadata from GitHub on every build to optimize CSS. This can be cached locally to avoid network latency.
• Icon Generation: It regenerates favicons and Apple touch icons on every build. This should be skipped if the source icon hasn't changed.

5. Minor Algorithmic Improvements¶

• Navigation Lookups: In PageGenerator.generate_post_page, the code uses all_posts.index(post) to find the current post's position for prev/next links. This is an O(N) operation called N times, leading to O(N^2) behavior. Pre-calculating a mapping would make this O(1).
• Markdown Instance Reuse: Several utility functions (markdown_to_plain_text, extract_first_paragraph) create a fresh markdown.Markdown instance on every call. Reusing a single instance (and calling .reset()) or caching the instance creation would reduce overhead.

Summary¶

The "Big Wins" are definitely optimizing backlink snippet extraction and implementing parallel parsing/rendering. Together, these would likely reduce generation time for large sites by 60-80% on modern hardware.

At first glance they all seem pretty sensible, and I like that it seems to have found some really obvious big improvements, and also the little wins that might have a cumulative effect. I strongly suspect the parallel generation suggestion is again going to be a non-win (and so for now I'm going to pass on it), but most of the other suggestions seem doable and worth trying out.

I think what I will do, rather than work through them all in one PR, is tackle one at a time. So, over the next few days, expect to see some PRs turn up and get merged (hopefully), as I try and tease some speed wins out of the code.

Looks like my Steam Controller is close! Very close!

Good job I updated the OS on the Steam Deck yesterday. It's almost like I anticipated this.

The new linting tool I've added to BlogMore has paid off already. While it is the case that it helped me find a couple of broken links and one or two other things to tidy, as I was working on the feature; by the time I released it, my blog was lint-free.

But last night I did a little more work on the slow migration of images over to WebP. As I've mentioned before: this is a process I'm doing by hand, one post at a time, for a couple of different reasons. The thing is, I'm in a part of my blog now where I was often posting about updates to projects I was working on (Tinboard being a good example), and the cover for all of the posts would be the same. To save having multiple copies of the cover image, all subsequent posts would point back to the first cover image¹.

So what was happening was, I'd have a cover image that got transitioned from PNG to WebP, and then the covers of a number of posts, later in time, would be broken. While I would get to them eventually, if I'd called it a day there and rebuilt my blog, those would have been published broken.

Using blogmore lint while making those changes yesterday evening alerted me to this right away.

After noticing a broken link in a post yesterday, I got to thinking that it would be useful to add a linter to BlogMore. So I've released v2.21.0 which adds linting support.

A number of things are checked and the results are broken down into things that are errors or warnings. Errors result from any of these checks:

• Ensures all posts and pages have valid YAML frontmatter. If a file cannot be parsed, it is reported as an error.
• Scans the generated HTML for links to non-existent internal paths (other posts, pages, categories, tags, archives, site features like search, or files in extras/).
• Checks that all <img> sources resolve to valid internal paths or files in the extras/ directory.
• Checks that the cover property in a post or page frontmatter points to a valid resource.
• Verifies that all page slugs listed in sidebar_pages actually exist.
• Checks that all internal-looking URLs in the links: and socials: configuration settings point to valid targets.

On the other hand, the following just result in a warning:

• Flags if a post is missing a title, category, tags, or a date.
• Reports if a post's date or modified date is set in the future.
• Notes if a post's modified date is earlier than its original publication date.
• Identifies if two or more posts share the exact same title.
• Flags inline images missing an alt attribute, or those with an empty/whitespace-only alt attribute.
• If clean_urls is enabled, warns if internal links point explicitly to index.html.
• Reports internal links using the full site_url (e.g., https://example.com/path/) instead of a root-relative path (/path/).

I feel like all of these cover most of the things that are low-cost to detect but have a positive impact on the state of the content of a blog.

One thing I've not done is any sort of checking of external links. This would be costly and could possibly have unintended consequences that I don't want to be messing with (perhaps a tool to export the list of external links for checking could be useful, at some point).

Having run this against this blog, I did find some things that needed cleaning up, mostly absolute links that could be turned into root-relative links (always good for making the content portable).

I'm going to make this a standard part of my "I'm ready to publish" check for this blog, and it should also be helpful as I carry on migrating the images in the blog over to WebP.

At the moment I'm working on a linting command for BlogMore. Having given up on Copilot/Claude for this, I've been having quite a bit of success with Gemini CLI. But while doing this, I've noticed some odd things with it. It does have this habit of cargo-culting some changes, or just rewriting code that doesn't need it.

For example, the tests for the new linting tool: it keeps adding import pytest near the top of the test file despite the fact that pytest doesn't get used anywhere in the code. Every time, I'll remove it, every time it adds more tests, it'll add it back.

Another thing I've noticed is it seems to be obsessed with adding indentation to empty lines. So, if you've got a line of code indented 8 spaces, then an empty line, then another line of code indented 8 spaces, it'll add 8 spaces on that empty line. That sort of thing annoys the hell out of me¹.

But the worst thing I just ran into was this. It had written this bit of code:

def lint_site(site_config: SiteConfig) -> int:
    """Convenience function to run the linter.

    Args:
        site_config: The site configuration.

    Returns:
        0 if no errors, 1 if errors were found.
    """
    linter = Linter(site_config)
    return linter.lint()

On the surface this seems fine: a function that hides just a little bit of detail while providing a simple function interface to a feature. But that use of a variable to essentially "discard" it the next line... nah. I dislike that sort of thing. The code can be just a little more elegant. So seeing this I edited it to be (removing the docstring for the purposes of this post):

def lint_site(site_config: SiteConfig) -> int:
    return Linter(site_config).lint()

Nice and tidy.

I then had Gemini work on something else in the linting code. What did I see towards the end of the diff? This!

Sneaky little shit!

Now, sure, the idea is you review all changes before you run with them, but knowing that it's likely that any given change might rewrite parts of the code that aren't related to the problem at hand adds a lot more overhead, and I wonder how often people using these tools even bother.

Following on from my first post about this, I've tweaked the script I'm using to backup a repo to GitLab and Codeberg:

#!/bin/sh

# Check if the current directory is a Git repository
if ! git rev-parse --is-inside-work-tree > /dev/null 2>&1; then
    echo "Error: This directory is not a Git repository."
    exit 1
fi

REPO_NAME="$1"

# If no repository name was provided, try to get it from the origin remote
if [ -z "$REPO_NAME" ]; then
    ORIGIN_URL=$(git remote get-url origin 2>/dev/null)
    if [ -n "$ORIGIN_URL" ]; then
        REPO_NAME=$(basename -s .git "$ORIGIN_URL")
    else
        echo "Error: No repository name provided and no 'origin' remote found."
        echo "Usage: $0 <repo-name>"
        exit 1
    fi
fi

echo "Configuring multi-forge backup sync for: $REPO_NAME"

# Set up the remote called backups. Anchor it to Codeberg.
git remote remove backups > /dev/null 2>&1
git remote add backups "ssh://git@codeberg.org/davep/${REPO_NAME}.git"

# Set up the push URLs.
git remote set-url --push backups "ssh://git@codeberg.org/davep/${REPO_NAME}.git"
git remote set-url --add --push backups "git@gitlab.com:davep/${REPO_NAME}.git"

# Only ever backup main.
git config remote.backups.push refs/heads/main:refs/heads/main

# Also backup all tags.
git config --add remote.backups.push 'refs/tags/*:refs/tags/*'

echo "----------------------------------------------------"
echo "Backups configured:"
git remote -v
echo "----------------------------------------------------"
echo "To perform the initial sync, run: git push backups"

### setup-forge-sync ends here

The changes from last time include:

• The repo name now defaults to whatever is used for GitHub, so I don't have to copy/paste it or type it out.
• It now backs up all the tags too.

I've been running with this for a couple of days now and it's proving really useful. Well, when Codeberg is available to push anything to...

At some point this morning I was looking for something on this blog and stumbled on a post that had a broken link. Not an external link, but an internal link. This got me thinking: perhaps I should add some sort of linting tool to BlogMore? I figured this should be doable using much of the existing code: pretty much work out the list of internal links, run through all pages and posts, see what links get generated, look for internal links¹, and see if they're all amongst those that are expected.

Later on in the day I prompted Copilot to have a go. Now, sure, I didn't tell it how to do it, instead I told it what I wanted it to achieve. I hoped it would (going via Claude, as I've normally let it) decide on what I felt was the most sensible solution (use the existing configuration-reading, page/post-finding and post-parsing code) and run with that.

It didn't.

Once again, as I've seen before, it seemed to understand and take into account the existing codebase and then copy bits from it and drop it in a new file. Worse, rather than tackle this using the relevant parts of the existing build engine, it concocted a whole new approach, again obsessing over throwing a regex or three at the problem.

I then spent the next 90 minutes or so, testing the results, finding false reports, finding things it missed, and telling it what I found and getting it to fix them. It did, but on occasion it seemed to special-case the fix rather than understand the general case of what was going on and address that.

Eventually, probably too late really, I gave up trying to nudge it in the right direction and, instead, decided it was time to be more explicit about how it should handle this². The first thing that bothered me was that it seemed to ignore the configuration object. Where BlogMore has a method of loading the configuration into an object, which can be passed around the code, but with the linter it loaded it up, pulled it all apart, and then passed some of the values as a huge parameter list. Because... reasons?

Anyway, I told it to cut that shit out and prompted it about a few other things that looked pretty bad too. Copilot/Claude went off and worked away on this for a while, using up my 6th premium request of the session, and then eventually came back with an error telling me I'd hit a rate limit and to come back in a few hours.

Could I have got it to where I wanted to be a bit earlier, with more careful prompting? No doubt. Will a lot of people? I suspect that's rather unlikely. This is one of the many things that make me pretty sceptical about this as the tool some sell it as, at least for the moment. I see often that it's written about or talked about as if it's a really useful coding buddy. It can be, at times, but it's hugely unreliable. Here I'm testing it by building something as a hobby, and I'm doing so knowing that there's no real consequence if it craps out on me. I'm also doing it safe in the knowledge that I could write the code myself, albeit at a far slower pace and with less available time. Not everyone this is aimed at has that going for them.

But these tools are still sold like they're the most reliable coding buddies going.

All that said: having hit the rate limit, and having squandered six premium requests on the problem with no real progress, I decided to use my Google Gemini coding allowance instead (which, in my experience so far, seems pretty generous). I threw more or less the same initial prompt at it, but this time I stressed that I really wanted it to use the existing engine where possible. It managed to pretty much one-shot the problem in about 9 minutes and used up just 2% of my daily quota³.

I've done a little more tidying up since, and I still need to properly review the result, but from what I can see of the initial results it's found all of the issues I wanted it to find, first time (something Claude didn't manage) and hasn't found any issues that don't exist (also something Claude didn't manage).

So I guess this time Gemini was the reliable buddy. But not knowing which buddy you can rely on makes for a pretty unreliable group of buddies.

I've just released BlogMore v2.20.0. There are five main changes in this release, and a lot of changes under the hood.

First, the under-the-hood stuff: while this isn't going to make a difference to anyone using BlogMore (at least it shouldn't make a difference -- if it does that's a bug that deserves reporting), the main site generation code has had a lot of work done on it to break it up. The motivation for this is to make the code easier to maintain, and to try and steer it in a direction closer to how I'd have laid things out had I written it by hand. The outcome of this is that, where the generator was over 2,000 lines of code in a single file, it's now a lot more modular and easier to follow.

Some other internals have been cleaned up too. Generally I've had a period of reviewing some of the code and reducing obvious duplication of effort, that sort of thing.

Now for the visible changes and enhancements in this release:

Improved word counts¶

Until now the word counting (and so the reading time calculations) were done by stripping most of the Markdown and HTML markup from the Markdown source. I wasn't too keen on this approach given that the codebase had a method of turning Markdown into plain text. So in this release the regex-based cleanup code is gone and word counts (and so reading times) use the same Markdown to plain text pipeline as anything else that needs to work on plain text.

Fixed a word count and reading time disparity¶

It was possible, in the stats page, to have one post appear to have the lowest or highest word count, but to not have the lowest or highest reading time. This was because reading times are always calculated to the minute and so there could be a disparity due to this rounding. The calculation of those stats now takes this into account.

Added an optional title to the socials¶

The socials setting in the configuration file has had an optional title property added for each entry. Until now the tooltip for an entry would be whatever the site was set to. Generally this works but if you have two or more accounts on the same site, or if you want to use a site value for something different, there was no way of making the tooltip more descriptive.

As an example, currently it's not possible to support Codeberg as a site. On the other hand git is available so it can be used as a substitute icon. The problem is, with this:

- site: git
  url: https://codeberg.org/davep

the tooltip will just say "git". With this update you can do this:

- site: git
  title: Codeberg
  url: https://codeberg.org/davep

and the tooltip will say "Codeberg".

As mentioned: this is optional. If there is no title the previous behaviour still applies.

Wall-clock time measurement¶

Yesterday, Andy posted about BlogMore's performance with respect to the different optional features. It's something I haven't really considered yet (possibly in part because this blog isn't anywhere near as big as his), but could be a good source of tinkering in the near future. His work to test the different parts of the tool did get me thinking though: it would be neat to know how long each part of the generation process takes.

So now, when a site is generated (either when using build or serve), the time of each step is printed, as is the overall generation time.

Markdown in HTML support¶

Yesterday I noticed that, on one of my posts, what had been written as a simple caption for an image wasn't rendering as it used to. The actual content of the Markdown source for the post contained this:

<center>
*(Yes, the tin was once mine and was once full; the early 90s were a
different time)*
</center>

While the text was centred, the raw Markdown was left in place (it should have been italic text). The reason for this is that BlogMore had never enabled Markdown-in-HTML support. So, as of this release, if the enclosing tag has markdown="1", any Markdown inside the tags will be parsed. This means the above becomes this:

<center markdown="1">
*(Yes, the tin was once mine and was once full; the early 90s were a
different time)*
</center>

I did think about doing something to turn it on by default (the fact that I didn't have such a "switch" in the post before suggests that Pelican did just always do this), but really I feel this approach is more flexible and less likely to result in unintended consequences.