Class: PgReports::Grafana::Exporter

Inherits:
Object
  • Object
show all
Defined in:
lib/pg_reports/grafana/exporter.rb

Overview

Renders selected reports in Prometheus exposition format. Severity is derived from REPORT_CONFIG thresholds in Dashboard::ReportsRegistry.

Constant Summary collapse

SEVERITY_ORDER = 
{"ok" => 0, "warning" => 1, "critical" => 2}.freeze
MAX_LABEL_VALUE_LENGTH = 
200
RESERVED_LABEL_NAMES = 
%w[report severity row error].freeze
MODULES = 
{
  queries: -> { Modules::Queries },
  indexes: -> { Modules::Indexes },
  tables: -> { Modules::Tables },
  connections: -> { Modules::Connections },
  system: -> { Modules::System },
  schema_analysis: -> { Modules::SchemaAnalysis }
}.freeze

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(favorites: PgReports.config.grafana_favorites, cache_ttl: PgReports.config.grafana_cache_ttl, clock: Time) ⇒ Exporter

Returns a new instance of Exporter.



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# File 'lib/pg_reports/grafana/exporter.rb', line 25

def initialize(favorites: PgReports.config.grafana_favorites,
  cache_ttl: PgReports.config.grafana_cache_ttl,
  clock: Time)
  @favorites = normalize(favorites)
  @cache_ttl = cache_ttl
  @clock = clock
end

Class Method Details

.render ⇒ Object 



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# File 'lib/pg_reports/grafana/exporter.rb', line 21

def self.render
  new.render
end

Instance Method Details

#render ⇒ Object 



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# File 'lib/pg_reports/grafana/exporter.rb', line 33

def render
  results = @favorites.map { |key, opts| collect(key, opts) }

  lines = []
  emit(lines, "pg_reports_issues", "Number of rows by severity for the report") do |emit|
    results.each do |r|
      next unless r[:ok]
      r[:severities].each { |sev, count| emit.call({report: r[:key], severity: sev}, count) }
    end
  end

  emit(lines, "pg_reports_rows", "Total rows returned by the report") do |emit|
    results.each { |r| emit.call({report: r[:key]}, r[:rows]) if r[:ok] }
  end

  emit(lines, "pg_reports_run_seconds", "Time spent collecting the report") do |emit|
    results.each { |r| emit.call({report: r[:key]}, r[:duration].round(4)) if r[:ok] }
  end

  emit(lines, "pg_reports_last_run_timestamp", "Unix timestamp of last collection") do |emit|
    results.each { |r| emit.call({report: r[:key]}, r[:timestamp]) if r[:ok] }
  end

  emit(lines, "pg_reports_up", "Whether collection succeeded (1) or failed (0)") do |emit|
    results.each do |r|
      labels = {report: r[:key]}
      labels[:error] = r[:error] unless r[:ok]
      emit.call(labels, r[:ok] ? 1 : 0)
    end
  end

  emit(lines, "pg_reports_row", "One series per row of the report (drives Grafana table panels). Each row column becomes a label.") do |emit|
    results.each do |r|
      next unless r[:ok] && r[:rows_data]
      r[:rows_data].each_with_index do |row_labels, idx|
        emit.call(row_labels.merge(report: r[:key], row: idx), 1)
      end
    end
  end

  (lines << "").join("\n")
end