Format mgr:5min and mgr:60min as YAML

[kinkie]

Also create a Time::YamlDateTime formatter

[kinkie]

Output after PR:

sample start time: 2024-04-25 22:58:18.33Z
sample end time: 2024-04-25 23:01:18.33Z
HTTP clientside statistics:
  requests per second: 52.28
  hits per second: 0.00
  errors per second: 0.39
  kbytes in per second: 6.06
  kbytes out per second: 42.78
  median service time secs: 0.10
  miss median service time secs: 0.10
  near miss median service time secs: 0.00
  near hit median service time secs: 0.00
  hit median service time secs: 0.00
HTTP serverside statistics:
  requests per second: 51.74
  errors per second: 0.00
  kbytes in per second: 39.25
  kbytes out per second: 10.76
  request per second: 51.74
  HTTP errors per second: 0.00
  HTTP kbytes in per second: 39.25
  HTTP kbytes out per second: 10.76
FTP serverside statistics:
  requests per second: 0.00
  errors per second: 0.00
  kbytes in per second: 0.00
  kbytes out per second: 0.00
other protocols serverside statistics:
  requests per second: 0.00
  errors per second: 0.00
  kbytes in per second: 0.00
  kbytes out per second: 0.00
ICP statistics:
  packets sent per second: 0.00
  packets received per second: 0.00
  queries sent per second: 0.00
  replies sent per second: 0.00
  queries received per second: 0.00
  replies received per second: 0.00
  replies queued per second: 0.00
  queries timed out per second: 0.00
  kbytes sent per second: 0.00
  kbytes received per second: 0.00
  query kbytes sent per second: 0.00
  reply kbytes sent per second: 0.00
  query kbytes received per second: 0.00
  reply kbytes received per second: 0.00
  query median service time secs: 0.00
  reply median service time secs: 0.00
DNS statistics:
  median service time seconds: 0.00
OS statistics:
  unlink requests per second: 0.00
  page faults per second: 0.44
  select loops per second: 160.23
  select FDs per second: 0.00
  average select FD period: 0.00
  median select FDs: 0.00
  swapouts per second: 0.00
  swapins per second: 0.00
  swap files cleaned per second: 0.00
  aborted requests per second: 0.39
Cacheability statistics:
  hit validation attempts per second: 0.00
  hit validation refusals due to locking per second: 0.00
  hit validation refusals due to zero size per second: 0.00
  hit validation refusals due to time limit per second: 0.00
Syscall statistics:
  disk open per second: 0.29
  disk close per second: 0.28
  disk reads per second: 0.00
  disk writes per second: 0.00
  disk seeks per second: 0.00
  disk unlinks per second: 0.00
  socket create per second: 47.50
  socket accepts per second: 52.30
  socket connects per second: 47.50
  socket binds per second: 0.01
  socket closes per second: 99.80
  socket reads per second: 104.83
  socket writes per second: 156.00
  socket recvfroms per second: 0.02
  socket sendtos per second: 0.01
CPU time seconds: 5.18
Wall time seconds: 180.01
CPU usage percent: 2.88

[rousskov]

This review is incomplete. Please apply applicable change requests from other pending YAML PRs to this one. Please stop posting YAML PRs until the current set lands.

[rousskov]

Foo::X operators should be declared in Foo. See commit 25ecffe.

[rousskov]

I do not see why we should name this format, but if you insist on naming it, please do not make the variable static and modifiable (there is no reason for any of that).

Suggested change

	static const char *yaml_time_format = "%Y-%m-%d %H:%M:%S";
	const auto yaml_time_format = "%Y-%m-%d %H:%M:%S";

[rousskov]

Why limit time to two digits?? Debugging often requires higher precision. Squid does not use two digits in most contexts IIRC. The chosen format does not specify precision AFAICT:

(\.[0-9]*[1-9])? # (fraction)

Please use all available digits.

[rousskov]

Do we really need to put YamlDateTime inside Time namespace? The class name already has "Time". And Yaml. And Date. Why pick Time out of those three? The namespace itself is highly questionable. I would keep this class outside that namespace.

[rousskov]

Please avoid implicit conversions by default:

Suggested change

	YamlDateTime(const struct timeval &tv) : tv_(tv) {};
	explicit YamlDateTime(const struct timeval &tv): tv_(tv) {};