[CT-662] [Feature] Allow the configuration of the timezone for timestamps in event logging

[Stefan-Rann]

Is this your first time opening an issue?

• [X] I have read the expectations for open source contributors

Describe the Feature

Currently the timestamp in event logging is always output in utc. It would be helpful to be able to set the time zone via a configuration or parameter (either local or any other time zone).

Describe alternatives you've considered

I have not found any alternatives. One has to live with utc.

Who will this benefit?

This would make it easier to evaluate the logs and help to avoid confusion. Additionally the evaluation of dbt logs in combination with other logs using lokal or any other timezone would be easier.

Are you interested in contributing this feature?

No response

Anything else?

No response

[gshank]

This sounds like a reasonable request. We're going to be looking at logging updates later in this quarter. I'm not sure if it would get onto the schedule or not, but we can take a look.

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[jtcohen6]

Reopening because we just got a duplicate opened in https://github.com/dbt-labs/dbt-core/issues/6319

Things I'm curious about: How would you want to configure this? Should there only be two options (local system time versus UTC)?

[ahuiiiiiii]

Reopening because we just got a duplicate opened in #6319

Things I'm curious about: How would you want to configure this? Should there only be two options (local system time versus UTC)?

can i add an option that set zonetime in dbt-core project configuration file?

[ahuiiiiiii]

sorry spelling error above should be timezone

[Stefan-Rann]

can i add an option that set zonetime in dbt-core project configuration file?

Yes, a project level setting would be cool to set the timezone by name. Additionally the option "local" would be great to use the system timezone without the need to explicitly define the timezone.

[Gunnnn]

Please! I see timestamps in log in UTC and its annoying =(

[Frunkh]

Atleast change record.extra[self.name] = datetime.utcnow().isoformat() to record.extra[self.name] = datetime.now().isoformat()

in logger.py So it respects the timezone of the system.. this is really annoying.

[sgaraycoa-de]

Adding my vote in favor of this issue

[jtcohen6]

Putting aside, for the moment, the question of creating a standalone configuration for this — I'd be supportive of switching from datetime.utcnow() to datetime.now(), so that the user's local system timezone is what's displayed in the logs. My sense is that most remotely-running orchestration systems would be in UTC, so it wouldn't be a change there.

Timestamp Doug (@dbeatty10) - does that proposed switch give you any trepidation?

[dbeatty10]

Main trepidation

For both datetime.utcnow() and datetime.now(), the Python datetimes are naive rather than aware [1][2] so the UTC offset is not explicit in either case.

Consequences

With the current dbt log output standardized to UTC, it's still comparable to other dbt logs (as long as you know it's UTC). But most human beings think about time in their local time zone.

When logs from dbt (or other systems) use naive timestamps that are localized, then comparing them really becomes quite the forensic exercise 😰

Possible solution

A possible solution is to use aware datetimes and print out the UTC offset. The trade-off is that this costs 6 extra characters in the log output.

$ dbt run
07:42:18-06:00  Running with dbt=1.4.4

============================== 2023-04-18 07:42:18.050150-06:00 | 07e7091e-7086-4fb5-9cab-643f3579e090 ==============================
07:42:18.050150-06:00 [info ] [MainThread]: Running with dbt=1.4.4

Python examples

from datetime import timezone, datetime as dt

Python	Output		UTC Offset
dt.utcnow().isoformat()	2023-04-18T13:42:18.050150	Naive	N/A
dt.now().isoformat()	2023-04-18T07:42:18.050150	Naive	N/A
dt.now().astimezone().isoformat()	2023-04-18T07:42:18.050150-06:00	Aware	System time zone
dt.now(timezone.utc).isoformat()	2023-04-18T13:42:18.050150+00:00	Aware	UTC

[nevdelap]

Just having it log in the system's timezone would be great. I'm lucky enough to be at UTC+10 so it is only mildly annoying, but still strange that it would be that way.

I've created this workaround, which also adds an elapsed time to the output. Someone might find it useful. 😉

[dbeatty10]

I'd propose two new configurations to handle this use case:

1. log_timestamp_tz_source: utc (default) | system
2. log_timestamp_print_offset: false (default) | true

*I didn't put a ton of thought into the names, so they could be shorted during design refinement as-needed. For example, maybe log_timestamp_tz_offset_print would be better, etc. Or maybe these two for brevity:

• log_tz_source
• log_tz_offset_print

### Example logic

`ts.py` ```python from datetime import timezone, datetime as dt OPTIONS_LOG_TIMESTAMP_TZ_SOURCE = ["utc", "system"] OPTIONS_LOG_TIMESTAMP_PRINT_OFFSET = [False, True] def get_now_aware_utc_tz(): return dt.now(timezone.utc) def get_now_aware_system_tz(): return dt.now().astimezone() def get_now_formatted(log_timestamp_tz_source="utc", log_timestamp_print_offset=False): # default to UTC aware_timestamp = get_now_aware_utc_tz() # default to omitting the UTC offset format = "%H:%M:%S" # use the system timezone if specfied if log_timestamp_tz_source == "system": aware_timestamp = get_now_aware_system_tz() # include the UTC offset if specfied if log_timestamp_print_offset: format = "%H:%M:%S %z" return aware_timestamp.strftime(format) for log_timestamp_tz_source in OPTIONS_LOG_TIMESTAMP_TZ_SOURCE: for log_timestamp_print_offset in OPTIONS_LOG_TIMESTAMP_PRINT_OFFSET: now_formatted = get_now_formatted(log_timestamp_tz_source, log_timestamp_print_offset) print(f"\nlog_timestamp_tz_source: {log_timestamp_tz_source}; log_timestamp_print_offset: {log_timestamp_print_offset}") print(now_formatted) ``` Run it: ```shell python ts.py ``` Example output: ``` $ python ts.py log_timestamp_tz_source: utc; log_timestamp_print_offset: False 19:58:19 log_timestamp_tz_source: utc; log_timestamp_print_offset: True 19:58:19 +0000 log_timestamp_tz_source: system; log_timestamp_print_offset: False 12:58:19 log_timestamp_tz_source: system; log_timestamp_print_offset: True 12:58:19 -0700 ```

Flags / global configs

CLI flags:

• --log-timestamp-tz-source
• --no-log-timestamp-print-offset / --log-timestamp-print-offset

environment variables:

• LOG_TIMESTAMP_TZ_SOURCE
• LOG_TIMESTAMP_PRINT_OFFSET

dbt_project.yml flags:

• log_timestamp_tz_source
• log_timestamp_print_offset

Usage

CLI flags:

dbt compile --log-timestamp-tz-source system
dbt compile --log-timestamp-tz-source utc
dbt compile --no-log-timestamp-print-offset
dbt compile --log-timestamp-print-offset

environment variables:

export LOG_TIMESTAMP_TZ_SOURCE=system
export LOG_TIMESTAMP_TZ_SOURCE=utc
export LOG_TIMESTAMP_PRINT_OFFSET=1
export LOG_TIMESTAMP_PRINT_OFFSET=true
export LOG_TIMESTAMP_PRINT_OFFSET=T
export LOG_TIMESTAMP_PRINT_OFFSET=0
export LOG_TIMESTAMP_PRINT_OFFSET=false
export LOG_TIMESTAMP_PRINT_OFFSET=F

dbt_project.yml flags:

flags:
  log_timestamp_tz_source: system
  log_timestamp_tz_source: utc
  log_timestamp_print_offset: true
  log_timestamp_print_offset: false

Rationale

The defaults would preserve backwards-compatibility.

The first config would allow using the system timezone wherever dbt is running from (whether it is a user's machine or a container orchestrated somewhere remotely).

The second config would allow the timestamps to be interpreted in an aware fashion rather than forcing either a naive interpretation or assuming UTC.

Rejected idea

One thing I considered and decided against:

• a log_timestamp_format config that would accept a format that can be passed to the datetime.strftime method.

The reason is that logs display a different level of granularity when emitted to the CLI versus the file logs. The first does not include fractional seconds, whereas the second does.

Also there is a different format when --log-format json vs. not. The former always emits a ISO8601-formatted string that ends in Z whereas the latter does not.

Risk reduction

If you are certain that your orchestration environment system time zone is set to UTC (and won't ever change!) or that your log ingestion can interpret localized timestamps properly (somehow), then you can set these flags within dbt_project.yml.

But to reduce risk of a non-UTC orchestration environment messing up log ingestion and parsing by a tool like Datadog, etc., you could configure these via environment variable in your local environment rather than using flags within dbt_project.yml:

export DBT_LOG_TIMESTAMP_TZ_SOURCE=system
export LOG_TIMESTAMP_PRINT_OFFSET=0

[jim256]

I'd also really like to see two options (local system time versus UTC) rather than always defaulting to UTC only.

[PORXavierM]

As somebody find solution for this? is a problem from python or dbt himself?

[dbeatty10]

@PORXavierM the timestamps are coming from the logging of dbt.

There is some of amount of configurability of the timestamps via the LOG_FORMAT and LOG_FORMAT_FILE configs. Here's a brief summary:

Log format	Time zone	Aware vs. naive	Precision
text	UTC	naive timestamp	second
debug	system local time zone	naive timestamp	microsecond
json	UTC	aware timestamp	microsecond

There's some more nitty-gritty code details discussed here.