Manage and preserve timezone information

[jeromesimeon]

Executing operations on date and time always returns output in UTC, even if it uses the local timezone of the engine. This can lead to confusion, for instance, calling startOf endOf on EST returns EST results but converted to UTC:

bash-3.2$ cat logic.ergo 
namespace org.accordproject.startendtest

import org.accordproject.time.*

contract StartEndTest over TemplateModel {
  // Simple Clause
    clause test(request : Request) : TestResponse {
    let date : DateTime = dateTime("2018-01-01T12:00:00.000Z");
    return TestResponse{
      startOfDay: startOf(date, "days"),
      endOfDay: endOf(date, "days")
    }
  }
}
bash-3.2$ ergorun model.cto logic.ergo --contract contract.json --request request.json --state state.json --contractname org.accordproject.startendtest.StartEndTest
12:22:11 - info:
{
  "response": {
    "startOfDay": "2018-01-01T05:00:00.000Z",
    "endOfDay": "2018-01-02T04:59:59.999Z",
    "$class": "org.accordproject.startendtest.TestResponse"
  },
  "state": {
    "$class": "org.accordproject.cicero.contract.AccordContractState",
    "stateId": "1"
  },
  "emit": []
}

The DateTime support in Ergo should allow:

• To parse/print in a given timezone
• To set the local timezone (possibly it should be part of the context)
• Maintain the timezone throughout the processing
• Handle UTC offset (e.g., +5:00)
• Handle legal timezones (e.g., EST)

[jeromesimeon]

Some better support for utcOffset in PR #522

[jeromesimeon]

Contract time zone is now obtained from API during execution and time zone-dependent operations take it into account.

See release 0.7.0

No plans to support legal time zones at the moment so I’m closing.