Implement loop output

This merge request implements output writing from the loop block.

Following conversations with interested parties:

• The loop block must have an output
• The loop block shall be notified when a loop user block writes on its outputs

Part of beat.core#84 (closed)

added enhancement label

changed milestone to %Soft loops

@samuel.gaist: Is this the one to be merged?

Not yet.

I have to rebase it and fix the conflicts as well as ensure that it is working properly with beat.core before going further.

added 38 commits

• 836cdc13...3e146f57 - 11 commits from branch master
• 944e3c82 - [test][prefix] Rename invalid_loop_output to invalid_loop_validate_output
• 7b3d31a6 - [data] Add warning message when no files where found on CachedDataSource setup
• b5fc0451 - [outputs] Add RemotelySyncedOutput
• 040d6b72 - [helpers] Create remotely synced output if socket is given
• 40dfccfd - [execution][algorithm] Pass loop socket when creating outputs
• b554ed02 - [algorithm] Add write method to runner
• f8eabdc4 - [execution][loop] Implement output setup and writing
• 4eb0c5a6 - [execution][messagehandlers] Add handling of remote write sync
• 9aedbc01 - [helpers] Add output parsing for loop
• 0549151d - [scripts][loop_execute] pre-commit cleanup
• 94515dfa - [scripts][loop_execute] Add output closing
• 4f9f3157 - [test][algorithm] Add loop/loop_user loading tests
• 69ee30e2 - [test][loop_executor] Update tests for loop output
• 33889a5a - [output] Add end data index parameter and make it a synchronous operation
• d5359ab5 - [loop] Pass the data loaders for proper output creation
• b266d0aa - [execution][algorithm] Improve error handling during process
• 4cbd0d57 - [data] Make glob pattern more precise
• 8aca5dd6 - [data] Make the missing indices error more verbose
• 44c49345 - [algorithm] Improve dataformat loading code
• f241a438 - [test][loop_executor] Refactor test to ensure proper run
• 611af973 - [algorithm] Improved Dataformat parsing
• 122f0a4f - [scripts][loop_execute] Implement user adaptation as done in execute
• 6b8a780b - [scripts][execute] pre-commit cleanup
• 2d173a8e - [scripts][execute] Make database and loop address options
• c88c6ffc - [scripts][execute] Cleanup cache parameter handling
• 61f54bae - [scripts][execute] Clean run directory parameter handling
• 0df59c40 - [scripts][execute] Cleanup user id handling

Compare with previous version

added 5 commits

• 49ce9738 - [scripts][execute] Make loop address an option
• 851dc6bd - [scripts][execute] Cleanup db_addr handling
• 2309b0eb - [scripts][execute] Cleanup cache parameter handling
• 80f425e6 - [scripts][execute] Clean run directory parameter handling
• 4231c55a - [scripts][execute] Cleanup user id handling

Compare with previous version

unmarked as a Work In Progress

@andre.anjos The code is now ready to be reviewed.

changed the description

mentioned in merge request beat.core!83 (merged)

Apart from the comments above, code looks OK. Thx.

resolved all discussions

merged

mentioned in commit 89f83797