summaryrefslogtreecommitdiff
path: root/spec/lib/gitlab/metrics/samplers/influx_sampler_spec.rb
blob: 81954fcf8c56459cd2681fb725ea5afe214d3757 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
require 'spec_helper'

describe Gitlab::Metrics::Samplers::InfluxSampler do
  let(:sampler) { described_class.new(5) }

  describe '#start' do
    it 'runs once and gathers a sample at a given interval' do
      expect(sampler).to receive(:sleep).with(a_kind_of(Numeric)).twice
      expect(sampler).to receive(:sample).once
      expect(sampler).to receive(:running).and_return(true, false)

      sampler.start.join
    end
  end

  describe '#sample' do
    it 'samples various statistics' do
      expect(sampler).to receive(:sample_memory_usage)
      expect(sampler).to receive(:sample_file_descriptors)
      expect(sampler).to receive(:sample_gc)
      expect(sampler).to receive(:flush)

      sampler.sample
    end

    it 'clears any GC profiles' do
      expect(sampler).to receive(:flush)
      expect(GC::Profiler).to receive(:clear)

      sampler.sample
    end
  end

  describe '#flush' do
    it 'schedules the metrics using Sidekiq' do
      expect(Gitlab::Metrics).to receive(:submit_metrics)
        .with([an_instance_of(Hash)])

      sampler.sample_memory_usage
      sampler.flush
    end
  end

  describe '#sample_memory_usage' do
    it 'adds a metric containing the memory usage' do
      expect(Gitlab::Metrics::System).to receive(:memory_usage)
        .and_return(9000)

      expect(sampler).to receive(:add_metric)
        .with(/memory_usage/, value: 9000)
        .and_call_original

      sampler.sample_memory_usage
    end
  end

  describe '#sample_file_descriptors' do
    it 'adds a metric containing the amount of open file descriptors' do
      expect(Gitlab::Metrics::System).to receive(:file_descriptor_count)
        .and_return(4)

      expect(sampler).to receive(:add_metric)
        .with(/file_descriptors/, value: 4)
        .and_call_original

      sampler.sample_file_descriptors
    end
  end

  describe '#sample_gc' do
    it 'adds a metric containing garbage collection statistics' do
      expect(GC::Profiler).to receive(:total_time).and_return(0.24)

      expect(sampler).to receive(:add_metric)
        .with(/gc_statistics/, an_instance_of(Hash))
        .and_call_original

      sampler.sample_gc
    end
  end

  describe '#add_metric' do
    it 'prefixes the series name for a Rails process' do
      expect(sampler).to receive(:sidekiq?).and_return(false)

      expect(Gitlab::Metrics::Metric).to receive(:new)
        .with('rails_cats', { value: 10 }, {})
        .and_call_original

      sampler.add_metric('cats', value: 10)
    end

    it 'prefixes the series name for a Sidekiq process' do
      expect(sampler).to receive(:sidekiq?).and_return(true)

      expect(Gitlab::Metrics::Metric).to receive(:new)
        .with('sidekiq_cats', { value: 10 }, {})
        .and_call_original

      sampler.add_metric('cats', value: 10)
    end
  end

  describe '#sleep_interval' do
    it 'returns a Numeric' do
      expect(sampler.sleep_interval).to be_a_kind_of(Numeric)
    end

    # Testing random behaviour is very hard, so treat this test as a basic smoke
    # test instead of a very accurate behaviour/unit test.
    it 'does not return the same interval twice in a row' do
      last = nil

      100.times do
        interval = sampler.sleep_interval

        expect(interval).not_to eq(last)

        last = interval
      end
    end
  end
end