Add dispatcher utility

[mraspaud]

Add the dispatcher utility.

client1:
  host: ftp://ftp.client1.com
  connection_parameters:
    credential_file: .netrc
  filepattern: '{platform_name}_{start_time}.{format}'
  directory: /input_data/{sensor}
  dispatch:
    - topics:
        - /level2/viirs
        - /level2/avhrr
      conditions:
        # key matches metadata items or provides default
        - product: [green_snow, true_color]
          sensor: viirs
        - product: [green_snow, overview]
          sensor: avhrr
          # special section "except" for negating
          except:
            platform_name: NOAA-15
    - topics:
        - /level3/cloudtype
      directory: /input/cloud_products
      conditions:
        - area: omerc_bb
          daylight: '<30'
          coverage: '>50'

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@358a759). Click here to learn what that means.
The diff coverage is 65.19%.

@@            Coverage Diff            @@
##             master      #37   +/-   ##
=========================================
  Coverage          ?   29.82%           
=========================================
  Files             ?       12           
  Lines             ?     1750           
  Branches          ?        0           
=========================================
  Hits              ?      522           
  Misses            ?     1228           
  Partials          ?        0

Impacted Files	Coverage Δ
trollmoves/server.py	0% <0%> (ø)
setup.py	0% <0%> (ø)
trollmoves/utils.py	64.47% <100%> (ø)
trollmoves/movers.py	28.04% <28.04%> (ø)
trollmoves/hooks.py	75% <75%> (ø)
trollmoves/dispatcher.py	89.67% <89.67%> (ø)
trollmoves/tests/test_dispatcher.py	98.06% <98.06%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 358a759...168697a. Read the comment docs.

[pnuu]

LGTM. Couple of typos in the docstrings

[pnuu]

Oh, and inotify needs to be added to install_requires.

[pnuu]

I'll give some more comments tomorrow morning.

[pnuu]

Could there be a condition for filename patterns? I'm thinking about messages coming from trollmoves transfers, which might need additional transfers to servers without trollmoves client capabilities, like external customers. Although now that I look at those messages I think there might be enought information even without this feature 🤔

[mraspaud]

I was hoping to be free from the filenames and just work with metadata...

[pnuu]

Isn't filename (or uid/uri) also metadata? 😁 Anyway, this can also be handled by having specific topics.

[pnuu]

LGTM, feel free to merge if you don't find anything to change.

[mraspaud]

Thanks. I'll test my current dispatch chains with the modifications to make sure it still works