Syslog rfc3164 location (timestamp) parameter

[jsirianni]

Description of Changes

Added a location parameter for overriding the default UTC timezone used by the syslog package.

This change is for RFC 3164 syslog only, as the timestamps do not include a timezone. RFC 5424 does not require this parameter, and will ignore it.

This resolves an issue where the agent is receiving syslog messages from a system using a timezone other than UTC for the timestamp.

Initially I thought I would need to modify SyslogParserConfig.ParserConfig.TimeParser, but I found that go-syslog is transforming the raw timestamp into a time.Time value before it reaches the syslog operator.

Please check that the PR fulfills these requirements

• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)
• Add a changelog entry (for non-trivial bug fixes / features)
• CI passes

[djaglowski]

Log Files	Logs / Second	CPU Avg (%)	CPU Avg Δ (%)	Memory Avg (MB)	Memory Avg Δ (MB)
1	1000	1.8793439	+0.24137425	123.52196	+0.49892426
1	5000	6.241509	-0.15516043	131.4872	-1.3073883
1	10000	12.20723	+0.034700394	140.42618	-0.45635986
1	50000	57.274982	-0.7234726	170.8529	-10.696396
1	100000	109.24248	-2.3760529	230.77802	-4.732895
10	100	2.327677	-0.017238379	128.2473	+4.695572
10	500	6.586356	-0.18968248	134.58566	-0.75956726
10	1000	13.827895	+0.8276186	144.0039	+0.22885132
10	5000	60.07107	-2.8395462	184.73303	+2.1736298
10	10000	122.56434	-10.776176	219.68845	-17.33136

[djaglowski]

This looks great.

[codecov]

Codecov Report

Merging #247 (74c69f2) into master (0c54a1d) will increase coverage by 0.01%.
The diff coverage is 75.00%.

@@            Coverage Diff             @@
##           master     #247      +/-   ##
==========================================
+ Coverage   71.47%   71.48%   +0.01%     
==========================================
  Files         102      102              
  Lines        5598     5604       +6     
==========================================
+ Hits         4001     4006       +5     
  Misses       1168     1168              
- Partials      429      430       +1     

Impacted Files	Coverage Δ
operator/builtin/parser/syslog/syslog.go	67.24% <75.00%> (-0.03%)	⬇️
operator/builtin/input/file/file.go	73.97% <0.00%> (-2.05%)	⬇️
operator/builtin/output/forward/forward.go	59.42% <0.00%> (+2.90%)	⬆️
operator/flusher/flusher.go	88.00% <0.00%> (+4.00%)	⬆️

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