Allow reading facets from filenames

[schlunma]

Description

This PR allows reading facets from filenames and also makes it much more flexible. Examples:

path = "/climate_data/value1/xyz/filename.nc"
template = "{facet1}/xyz/{facet2}.nc"
path2facets(path, template) = {"facet1": "value1", "facet2": "filename"}

path = "/climate_data/Tier3/ds/tas_ds_Amon_1993.nc"
template = "Tier{tier}/{dataset}/{short_name}_*.nc"
path2facets(path, template) = {"tier": "3", "dataset": "ds", "short_name": "tas"}

path = "/climate_data/value-1-value-2/value-2/filename.nc"
template = "{facet1}-{facet2}/{facet2}/{facet3}.nc"
path2facets(path, template) = {"facet1": "value-1", "facet2": "value-2", "facet3", "filename"}

path = "/climate_data/1/2345/678/910/11/filename.nc"
template = "{f1}/{f2}{f3}{f4}{f5}/{f6}{f7}{f8}/{f9}{f10}/{f11}/{filename}.nc"
path2facets(path, template) = {"f1": "1", "f11": "11", "filename": "filename"}

# To be backwards-compatible
path = "/climate_data/value1/xyz/filename.nc"
template = "{facet1.upper}/xyz/{facet2.lower}.nc"
path2facets(path, template) = {"facet1": "value1", "facet2": "filename"}

Internally, this uses the regex engine to do all the heavy lifting. For this, the templates are converted to regex patterns that include named capture groups, e.g.

template = "{f2}/{f3}[._]{f4}*"
regex_pattern = r"(?P<f2>[^_/]*?)/(?P<f3>[^_/]*?)[\._](?P<f4>[^_/]*?).*?"

Supersedes #1943.

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Checklist

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• 🧪 The new functionality is relevant and scientifically sound
• 🛠 This pull request has a descriptive title and labels
• 🛠 Code is written according to the code quality guidelines
• 🧪 and 🛠 Documentation is available
• 🛠 Unit tests have been added
• 🛠 Changes are backward compatible
• 🛠 Any changed dependencies have been added or removed correctly
• 🛠 The list of authors is up to date
• 🛠 All checks below this pull request were successful --> I think the remaining Codacy issue can be ignored since it's probably not a good idea to mess with the __init__ method of a dataclass.

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.12%. Comparing base (7f23600) to head (d1d8c5a).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2725      +/-   ##
==========================================
+ Coverage   95.10%   95.12%   +0.01%     
==========================================
  Files         258      258              
  Lines       15028    15053      +25     
==========================================
+ Hits        14293    14319      +26     
+ Misses        735      734       -1     

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