file input: optional file_name_resolved and file_path_resolved labels

[jsirianni]

Description of Changes

Add optional file_name_resolved and file_path_resolved labels to file input

Ported from OTEL: https://github.com/open-telemetry/opentelemetry-log-collection/pull/189/files

With new labels enabled

{
  "timestamp": "2021-07-15T19:39:39.289773231-04:00",
  "severity": 0,
  "labels": {
    "file_name": "in-symlink.json",
    "file_name_resolved": "test.json",
    "file_path": "./log/in-symlink.json",
    "file_path_resolved": "/tmp/test.json"
  },
  "record": {
    "key-symlink": "value"
  }
}
{
  "timestamp": "2021-07-15T19:39:39.289788021-04:00",
  "severity": 0,
  "labels": {
    "file_name": "in.json",
    "file_name_resolved": "in.json",
    "file_path": "./log/in.json",
    "file_path_resolved": "/home/jsirianni/go/src/github.com/observiq/stanza/log/in.json"
  },
  "record": {
    "key": "value"
  }
}

Config

pipeline:
- type: file_input
  include: 
  - ./log/in.json
  - ./log/in-symlink.json
  include_file_path: true
  include_file_name_resolved: true
  include_file_path_resolved: true
  start_at: beginning
- type: json_parser
- type: stdout

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

[codecov]

Codecov Report

Merging #364 (15a78e4) into master (0019926) will decrease coverage by 0.14%.
The diff coverage is 84.91%.

@@            Coverage Diff             @@
##           master     #364      +/-   ##
==========================================
- Coverage   73.33%   73.19%   -0.14%     
==========================================
  Files         124      124              
  Lines        7948     7974      +26     
==========================================
+ Hits         5828     5836       +8     
- Misses       1629     1644      +15     
- Partials      491      494       +3     

Impacted Files	Coverage Δ
operator/builtin/input/file/reader.go	71.05% <60.00%> (-1.40%)	⬇️
operator/builtin/input/file/config.go	80.00% <100.00%> (+2.86%)	⬆️
operator/builtin/input/file/file.go	79.06% <100.00%> (-3.66%)	⬇️
operator/buffer/memory.go	75.33% <0.00%> (-4.67%)	⬇️
operator/builtin/output/forward/forward.go	60.49% <0.00%> (-1.23%)	⬇️
operator/builtin/output/otlp/otlp.go	68.13% <0.00%> (+3.30%)	⬆️

---

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[djaglowski]

Log Files	Logs / Second	CPU Avg (%)	CPU Avg Δ (%)	Memory Avg (MB)	Memory Avg Δ (MB)
1	1000	1.4654696	+0.06888926	127.57207	-0.35573578
1	5000	5.017335	-0.15506506	143.12595	+8.293381
1	10000	10.603407	+0.5514803	145.74124	+1.5323181
1	50000	52.67129	+3.5157433	178.35547	+1.3708191
1	100000	83.623116	-16.75943	1080.219	+836.9307
10	100	1.982852	+0.051787138	135.11853	+4.852371
10	500	6.0347166	+0.08624411	136.81923	-3.0370483
10	1000	12.05211	+0.776042	151.88861	+6.9226837
10	5000	56.27653	+0.12049866	182.16837	+7.0234375
10	10000	73.08633	-32.21685	602.31885	+374.56076