More precise timestamps in structured log view of dashboard

[KalleOlaviNiemitalo]

In Aspire 8.0.0-preview.4.24156.9, the "Timestamp" column of the "Structured logs" page of the dashboard shows only one-second precision, e.g. "19.01.29". I'd like to see timestamps with more precision, like "19.08.17,7547722". That would let me see how much time passed between consecutive log entries, even if they occurred during the same second. In OpenTelemetry Protocol, LogRecord appears to support nanosecond precision.

I found a related issue #115 but that one seems to concern how the Dashboard configures the console loggers of other processes, rather than how it displays the timestamps it has received over OTLP.

[leslierichardson95]

@JamesNK what's your take on this scenario?

[JamesNK]

I think showing up to 3 decimal places in the UI is good. That's what most people want, most of the time, while keeping a clean UI. However, I think the tooltip can be improved to show the full precision.

Current:

[KalleOlaviNiemitalo]

Aspire 8.0.0-preview.4.24156.9 already attempted to display milliseconds in the timestamp column:

aspire/src/Aspire.Dashboard/Components/Pages/StructuredLogs.razor

Lines 85 to 87 in 692dc41

	<TemplateColumn Title="@Loc[nameof(Dashboard.Resources.StructuredLogs.StructuredLogsTimestampColumnHeader)]" TooltipText="@(context => FormatHelpers.FormatDateTime(context.TimeStamp, true, CultureInfo.CurrentCulture))" Tooltip="true">
	@FormatHelpers.FormatTimeWithOptionalDate(context.TimeStamp, includeMilliseconds: true)
	</TemplateColumn>

I think that did not work because it searched for the seconds field using the regular expression (:ss|:s):

aspire/src/Aspire.Dashboard/Utils/FormatHelpers.cs

Lines 17 to 18 in 692dc41

	[GeneratedRegex("(:ss|:s)")]
	private static partial Regex MatchSecondsInTimeFormatPattern();

and CultureInfo.CurrentCulture.DateTimeFormat.LongTimePattern actually was "H.mm.ss", which does not include a colon, so FormatHelpers did not know where they should insert the milliseconds.

Now on the "main" branch, FormatHelpers are still using colons in the regular expression:

aspire/src/Aspire.Dashboard/Utils/FormatHelpers.cs

Lines 29 to 30 in e24eb81

	[GeneratedRegex("(:ss|:s)")]
	private static partial Regex MatchSecondsInTimeFormatPattern();

Because of that, I suspect it still does not work.

[JamesNK]

What culture are you using? Can you show a screenshot of what you see?

[KalleOlaviNiemitalo]

The culture is "fi-FI".

[KalleOlaviNiemitalo]

[KalleOlaviNiemitalo]

I wonder if the regexp could be just (s|ss) with no separators; that ought to find the longest leftmost match anyway. I guess not; it would incorrectly match s within quotation marks too.

[KalleOlaviNiemitalo]

"da-DK" doesn't use colons in LongTimePattern either: "HH.mm.ss"

[JamesNK]

Thanks, that's a bug. Fix looks pretty simple: #3215

[drewnoakes]

We should file an issue with the docs repo too, as this approach came from there.

[KalleOlaviNiemitalo]

The wrong regex was in https://github.com/dotnet/samples/blob/b6f2197113dfd947171bf99e79cb24b303b75b2d/samples/snippets/csharp/VS_Snippets_CLR/Formatting.HowTo.Millisecond/cs/Millisecond.cs#L31 already seven years ago.

[KalleOlaviNiemitalo]

I filed the docs issue at dotnet/docs#40356.

The French (Canada) culture "fr-CA" has LongTimePattern = HH 'h' mm 'min' ss 's'. The updated regular expression (:ss|\.ss|:s|\.s) from #3215 still won't match anything in that. I guess this should be transformed to HH 'h' mm 'min' ss','fff 's'.

[KalleOlaviNiemitalo]

PS C:\> [CultureInfo]::GetCultures([CultureTypes]::SpecificCultures) | Group-Object -Property { $_.DateTimeFormat.LongTimePattern }

Count Name                      Group
----- ----                      -----
    1  HH:mm:ss                 {my-MM}
    2 H:m:s                     {yo-BJ, yo-NG}
   23 H:mm:ss                   {ar-IL, ca-AD, ca-ES, ca-ES-VALENCIA…}
    1 H:mm:ss 'ч'.              {bg-BG}
  162 h:mm:ss tt                {aa-DJ, aa-ER, aa-ET, af-NA…}
    3 H.mm.ss                   {en-FI, fi-FI, smn-FI}
    1 HH 'h' mm 'min' ss 's'    {fr-CA}
  344 HH:mm:ss                  {af-ZA, agq-CM, ar-KM, ar-MA…}
    3 hh:mm:ss tt               {gu-IN, kn-IN, sa-IN}
    6 HH.mm.ss                  {da-DK, da-GL, en-DK, id-ID…}
    1 tt 'ga' h:mm:ss           {ee-GH}
    5 tt h:mm:ss                {ko-KP, ko-KR, ta-IN, ta-MY…}
    1 tt h.mm.ss                {as-IN}
    7 tth:mm:ss                 {zh-Hans-CN, zh-Hans-HK, zh-Hans-MO, zh-Hans-SG…}

[KalleOlaviNiemitalo]

Apart from the time separator problem, I'd suggest injecting a backslash \ in front of each character of the NumberDecimalSeparator rather than single quotes ' around it, in order to ensure that ToString will parse those characters as literals even if one of them is a single quote character itself.

aspire/src/Aspire.Dashboard/Utils/FormatHelpers.cs

Line 66 in e5605b8

return MatchSecondsInTimeFormatPattern().Replace(longTimePattern, $"$1'{key.NumberDecimalSeparator}'{millisecondFormat}");