Update schema

[tacaswell]

This replaces #2

rendered docs: http://tacaswell.github.io/docs/arch/arch.html

[dchabot]

• update diagram to include sample & snowflake in run_header boundary \ xfig
• integration time in schema?
• capture rules for inserting arbitrary keys:values into documents (custom = { }, etc) **
• events - seqno should be required and clearly defined
• datetime not required; for human readability only
• re-examine value-field of event
• descriptor type-field ; probably not string

Naming:

ev_desc ——> descriptor seq_no ——> seq_num

begin_run_event

• owner, project are required. Maybe group id too.
• scan_id MUST be an int? shoot me now...

event

• ‘data’ properties are currently proposed in the schema to be a dict \ data : { ‘chanX’ : {‘value’: number, ‘timestamp’: number}, }
• new proposal is to represent this as a tuple (‘twopul’): \ data : { ‘chanX’: (number, number), ‘chanY’: (number, number), }

end_run

start_id - get rid of this? check with SW reason - string, optional. Can drop exception trace here, on occurrence. completion_state - required. DC to propose small enum pool?

[danielballan]

This is not quite up to date, but it's a step in the right directly and it includes some mocking that will help me build the docs on my OSX laptop. So, merging.