Best practices to generate pretty reports

[Tobias Pfeiffer]

Hi,

I have a fairly long history of transactions in my ledger files and I
would like to generate some pretty reports from this data. Think a one-
page PDF (or HTML) file that opens with a sentence like "this month's
revenue was X, expenses were Y, P% higher than average" and then has
some charts about, say, distribution of expenses, historical data,
comparison with forecast data.

I guess many people on this list have a similar thing running already,
so I would like to hear about recommendations with respect to
toolchain, libraries, etc. that you are using.

Currently I have an emacs org-mode file and use babel to get the ledger
output, as follows:

```
#+TITLE: Financial Report
#+PROPERTY: header-args :results output :exports results :cache true
#+PROPERTY: header-args+ :var F="-f all.ledger" :var MONTH="sep 2019"

#+BEGIN_HTML
<link rel="stylesheet" href="web/graphs.js" />
#+END_HTML

#+BEGIN_SRC sh
PARAMS="${F} --effective -p ${MONTH}"
ledger balance $PARAMS Expenses
#+END_SRC
```

Then the HTML export contains a <pre> block with the ledger output and
my script in `web/graphs.js` parses it and creates some charts.

It somehow works that way, but I don't think it's a very nice pipeline.
It's all very tightly coupled and seems fairly fragile, I need to parse
the output of ledger in JavaScript, the application logic to compute
averages etc. is also in JavaScript, there are a lot of components
involved (which makes it hard to debug), and still it is not simple to
generate a simple sentence like "this month's revenue was X".

If anyone has any suggestions or can point at tools suited for that
purpose, please let me know.

Thanks
Tobias

[Jim Robinson]

Have you considered using the Python API?

https://www.ledger-cli.org/3.0/doc/ledger3.html#Extending-with-Python

Python has lots of libraries, including statistics, html templating and PDF APIs, so I imagine you could build what you wanted within it.

[Tobias Pfeiffer]

Hi,

To be honest, since the openSUSE ledger packages don't come with Python
bindings I haven't looked into the Python API too deeply; but I guess I
will end up using Python one way or another for the reasons you
mentioned. Maybe I should start by packaging the Python bindings for
openSUSE ;-)

Thanks for your help
Tobias

[Yuri Khan]

On Thu, 17 Oct 2019 at 19:39, Tobias Pfeiffer <tgpfe...@web.de> wrote:

> To be honest, since the openSUSE ledger packages don't come with Python
> bindings I haven't looked into the Python API too deeply; but I guess I
> will end up using Python one way or another for the reasons you
> mentioned. Maybe I should start by packaging the Python bindings for
> openSUSE ;-)

You can also parse the output of ‘ledger xml’. It gives you the data
equivalent to ‘ledger register’ though, so you may have to calculate
the balances on your own.