Fail and cancel deploy on Franklin Warning

[rikhuijzer]

As discussed in #1357.

Fixes #1357

This is the hacky and quick fix. It greps the logs, for "Franklin Warning". So, this assumes that Franklin prints the text "Franklin Warning" when something bad happens. In my experience, it works quite well because any parse or runtime error will give this warning. However, note that this doesn't detect missing images and/or probably other problems. For my own blog, this grep hack has worked for a year now and works quite well. CI has failed quite a lot of times without me expecting that it would fail, which is a good thing.

Note that the output isn't printed immediately to stdout and only to build.log. In my experience, that's fine. The only difference is that you have to wait a few more minutes before the stdout becomes visible.

Also, I've added some whitespace between the steps for readability.

[rikhuijzer]

Okay, it doesn't fail now for some reason, but this approach should work. The logs of the breaking post contain "Franklin Warning" (https://github.com/JuliaLang/www.julialang.org/runs/3383439513):

┌ Franklin Warning: in <index.md>
│ Encountered an issue processing 'index.md' in w.julialang.org/blog.
│ Verify, then re-start the Franklin server.
│ The error is displayed below:
│ Franklin.OCBlockError("I found the opening token 'MATH_A' but not the corresponding closing token.", "Context:\n\t... this year, raising ~\$4,000! If you missed ... (near line 32)\n\t                        ^---\n")

[giordano]

Let's add some colour

[DilumAluthge]

Just to test this out, can you intentionally introduce the kind of syntax error that #1356 had, and we can demonstrate that CI then fails.

[DilumAluthge]

Ah, I see you kind of tried that out above.

Maybe try a different kind of syntax error?

It would definitely be good to show that we can make CI fail with this.

[DilumAluthge]

@tlienart Any suggestions for a syntax error that we can push to this PR to demonstrate that CI fails?

[tlienart]

Note in passing that in the time we've had the site on Franklin the main issue I'm aware of is the $ sign not being escaped. So e.g. grant body XXX gave us $5000 instead of grant body XXX gave us \$5000 so if the deploy script here can catch that then it's already a big step in my opinion (and hopefully will last long enough for me to throw the error on the Franklin side)

[DilumAluthge]

I just pushed a commit that adds the text "one dollar plus one dollar equals $2" to one of the markdown files.

[DilumAluthge]

Success!

[DilumAluthge]

@rikhuijzer @tlienart Once CI is green, is this good to merge?

[tlienart]

Good stuff! merging, thanks @rikhuijzer and to all for the reviews :)

[DilumAluthge]

Thank you @rikhuijzer!