Benchmark Data

Summary Links

svcrunner/jsonlog.

svcrunner/jsonlog

Benchmark Data

Benchmark	Runs	Ns/Op	Allocs/Op	Bytes/Op	MB/Sec
Attributes	1,000,000	1,059.00	3	280	392.75
Big Group	34,441	35,892.00	14	56,137	293.63
Disabled	404,765,176	2.97	0	0	0.00
Key Values	1,000,000	1,089.00	3	280	382.01
Logging	59,827	20,482.00	0	0	439.46
Simple	4,827,558	242.30	0	0	359.02
Simple Source	4,799,905	260.40	0	0	330.23
With Attrs Attributes	1,000,000	1,085.00	4	288	715.87
With Attrs Key Values	1,000,000	1,118.00	4	288	695.00
With Attrs Simple	3,873,990	339.10	1	8	1,320.96
With Group Attributes	1,000,000	1,076.00	4	296	399.67
With Group Key Values	1,000,000	1,114.00	4	296	385.85

Benchmark Charts

Warnings

Required

LevelVar Unable to change level during execution via LevelVar

Slog handlers can use LevelVar to specify the handler logging level. Unlike specifying a Level (which is actually an int), a LevelVar is supposed to be changeable during program execution.

Verify: Level Var		level not changed

SlogTest Failure of embedded slog/slogtest

Documentation on building a handler suggests testing using slog/slogtest, part of the Go release since 1.21. While the verification suite includes tests patterned after those in slogtest, an additional single test invokes the slogtest testing sequence (involving multiple tests). Since this is a separate package, all error messages are returned at once. This is the only warning that affects TestSlogTest and all of its error messages.

Verify: Slog Test

missing key "msg"
this test expects slog.TimeKey, slog.LevelKey and slog.MessageKey

missing key "msg"
a Handler should handle the WithGroup method

missing key "msg"
a Handler should handle multiple WithGroup and WithAttr calls

missing key "msg"
a Handler should not output groups if there are no attributes

Implied

MessageKey Wrong message key (should be 'msg')

The field name of the "message" key should be msg.

Verify: Canceled Context		`message`

Verify: Canceled Context		`message`

Verify: Canceled Context		`message`

Verify: Keys		`message`

Verify: Source Key		`message`

Verify: Zero PC		`message`

Verify: Zero Time		`message`

NoReplAttr HandlerOptions.ReplaceAttr not available

If HandlerOptions.ReplaceAttr is provided it should be honored by the handler. However, documentation on implementing handler methods seems to suggest it is optional.

Verify: Replace Attr		too many attributes: 6, alpha == beta, change still exists, remove still exists

Verify: Replace Attr Basic		time field still exists message field still exists source ==

Verify: Replace Attr Fn Change Key		too few attributes: 3 no message key message not string

Verify: Replace Attr Fn Level Case		level value not null

Verify: Replace Attr Fn Multi
	{ "group": { "alpha": "omega", "pi": 3.141592653589793, "subGroup": { "alpha": "omega", "e": 2.718281828459045, "goober": "snoofus", "oneMore": { "alpha": "omega", "gibbering": "lunatic", "phi": 1.618033988749895 } } }, "level": "INFO", "message": "This is a message", "time": "2025-02-16T01:41:19.49671943Z" }
Verify: Replace Attr Fn Remove Empty Key

Verify: Replace Attr Fn Remove Time		time value not empty string

SourceKey Source data not logged when AddSource flag set

Handlers should log source data when the slog.HandlerOptions.AddSource flag is set.

Bench: Simple Source		no 'source' key
	{ "level": "INFO", "message": "This is a message", "time": "2025-02-16T01:39:50.73380189Z" }
Verify: Source Key		no 'source' key
	{ "level": "INFO", "message": "This is a message", "time": "2025-02-16T01:41:19.497315904Z" }

Suggested

Duplicates Duplicate field(s) found

Some handlers (e.g. slog.JSONHandler) will output multiple occurrences of the same field name if the logger is called with multiple instances of the same field, generally by using WithAttrs and then the same fields in the eventual log call (e.g. Info). This behavior is currently under debate with no resolution at this time (2024-01-15) and a release milestone of (currently unscheduled) Go 1.23, (whereas Go Release 1.22 is currently expected in February 2024).

Verify: Attribute Duplicate		map[alpha:2 charlie:3]

Verify: Attribute With Duplicate		map[alpha:2 charlie:3]

DurationString slog.Duration() logs a string representation instead of nanoseconds

The slog.JSONHandler uses nanoseconds for time.Duration but some other handlers use a string representation.

Verify: Group Duration		8h3m22s
	{ "group": { "inner": "8h3m22s" }, "level": "INFO", "message": "This is a message", "outer": "8h3m22s", "time": "2025-02-16T01:41:19.49527052Z" }
Verify: Log Attributes		1m0s
	{ "any": [ "alpha", "omega" ], "boolean": true, "goober": "snoofus", "howLong": "1m0s", "level": "INFO", "message": "This is a message", "minus": -64, "pi": 3.141592653589793, "skidoo": 23, "time": "2025-02-16T01:41:19.496392184Z", "unsigned": 79, "when": "2025-02-16T01:41:19.49638976Z" }

NoEmptyName Attributes with empty names are not logged

Until documented otherwise, an attribute with an empty field name ("") and a non-nil value should be logged.

Empty field names are logged by the JSONHandler.Handle() implementation

Verify: Attribute Empty Name
	{ "first": "one", "level": "INFO", "message": "This is a message", "pi": 3.141592653589793, "time": "2025-02-16T01:41:19.493095344Z" }
Verify: Attribute With Empty Name
	{ "first": "one", "level": "INFO", "message": "This is a message", "pi": 3.141592653589793, "time": "2025-02-16T01:41:19.493399917Z" }
Verify: Attributes Not Empty
	{ "first": "one", "level": "INFO", "message": "This is a message", "pi": 3.141592653589793, "time": "2025-02-16T01:41:19.493696356Z" }
Verify: Attributes With Not Empty
	{ "first": "one", "level": "INFO", "message": "This is a message", "pi": 3.141592653589793, "second": 2, "time": "2025-02-16T01:41:19.493899743Z" }

Handler svcrunner/jsonlog

Benchmark Data

Warnings