Class: Prometheus::ApiClient::Client

Inherits:
Object
  • Object
show all
Defined in:
lib/prometheus/api_client/client.rb

Overview

Client contains the implementation for a Prometheus compatible api_client.

Defined Under Namespace

Classes: RequestError

Constant Summary collapse

DEFAULT_ARGS =

Default paramters for creating default client

{
  url: 'http://localhost:9090',
  path: '/api/v1/',
  credentials: {},
  options: {
    open_timeout: 2,
    timeout: 5,
  },
}.freeze

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Client

Create a Prometheus API client:

A default client is created if options is omitted.

Parameters:

  • options (Hash) (defaults to: {})

Options Hash (options):

  • :url (String) —

    server base URL.

  • :params (Hash) —

    URI query unencoded key/value pairs.

  • :headers (Hash) —

    Unencoded HTTP header key/value pairs.

  • :request (Hash) —

    Request options.

  • :ssl (Hash) —

    SSL options.

  • :proxy (Hash) —

    Proxy options.



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# File 'lib/prometheus/api_client/client.rb', line 35

def initialize(options = {})
  options = DEFAULT_ARGS.merge(options)

  @client = Faraday.new(
    faraday_options(options),
  )
end

Instance Method Details

#faraday_headers(credentials) ⇒ Object

Helper function to evalueate the low level headers option



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# File 'lib/prometheus/api_client/client.rb', line 137

def faraday_headers(credentials)
  return unless credentials[:token]

  {
    Authorization: 'Bearer ' + credentials[:token].to_s,
  }
end

#faraday_options(options) ⇒ Object

Helper function to create the args for the low level client



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# File 'lib/prometheus/api_client/client.rb', line 146

def faraday_options(options)
  {
    url: options[:url] + options[:path],
    proxy: faraday_proxy(options[:options]),
    ssl: faraday_verify_ssl(options[:options]),
    headers: faraday_headers(options[:credentials]),
    request: {
      open_timeout: options[:options][:open_timeout],
      timeout: options[:options][:timeout],
    },
  }
end

#faraday_proxy(options) ⇒ Object

Helper function to evalueate the low level proxy option



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# File 'lib/prometheus/api_client/client.rb', line 122

def faraday_proxy(options)
  options[:http_proxy_uri] if options[:http_proxy_uri]
end

#faraday_verify_ssl(options) ⇒ Object

Helper function to evalueate the low level ssl option



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# File 'lib/prometheus/api_client/client.rb', line 127

def faraday_verify_ssl(options)
  return unless options[:verify_ssl]

  {
    verify: options[:verify_ssl] != OpenSSL::SSL::VERIFY_NONE,
    cert_store: options[:ssl_cert_store],
  }
end

#get(command, options) ⇒ Object

Issues a get request to the low level client.



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# File 'lib/prometheus/api_client/client.rb', line 94

def get(command, options)
  @client.get(command, options)
end

#label(label, options = {}) ⇒ Object

Returns a list of label values for a provided label name:

No options used.

Parameters:

  • label (String) —

    Label name

  • options (Hash) (defaults to: {}) 


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# File 'lib/prometheus/api_client/client.rb', line 89

def label(label, options = {})
  run_command("label/#{label}/values", options)
end

#query(options) ⇒ Object

Evaluates an instant query at a single point in time:

The current server time is used if the time parameter is omitted.

Parameters:

  • options (Hash)

Options Hash (options):

  • :query (String) —

    Prometheus expression query string.

  • :time (String) —

    <rfc3339 | unix_timestamp> Evaluation timestamp. Optional.

  • :timeout (String) —

    Evaluation timeout. Optional. Defaults to and is capped by the value of the -query.timeout flag.



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# File 'lib/prometheus/api_client/client.rb', line 53

def query(options)
  run_command('query', options)
end

#query_range(options) ⇒ Object

Evaluates an expression query over a range of time:

The current server time is used if the time parameter is omitted.

Parameters:

  • options (Hash)

Options Hash (options):

  • :query (String) —

    Prometheus expression query string.

  • :start (String) —

    <rfc3339 | unix_timestamp> Start timestamp.

  • :end (String) —

    <rfc3339 | unix_timestamp> End timestamp.

  • :step (String) —

    <duration> Query resolution step width.

  • :timeout (String) —

    Evaluation timeout. Optional. Defaults to and is capped by the value of the -query.timeout flag.



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# File 'lib/prometheus/api_client/client.rb', line 69

def query_range(options)
  run_command('query_range', options)
end

#run_command(command, options) ⇒ Object

Issues a get request to the low level client, and evalueate the response JSON.



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# File 'lib/prometheus/api_client/client.rb', line 100

def run_command(command, options)
  response = get(command, options)

  JSON.parse(response.body)['data']
rescue
  raise RequestError, 'Bad response from server'
end

#targets(options = {}) ⇒ Object

Returns an overview of the current state of the Prometheus target discovery:

No options used.

Parameters:

  • options (Hash) (defaults to: {}) 


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# File 'lib/prometheus/api_client/client.rb', line 79

def targets(options = {})
  run_command('targets', options)
end

#update_query(query, labels) ⇒ Object

Add labels to simple query variables.

Example:

"cpu_usage" => "cpu_usage{labels...}"
"sum(cpu_usage)" => "sum(cpu_usage{labels...})"
"rate(cpu_usage[5m])" => "rate(cpu_usage{labels...}[5m])"

Note:

Not supporting more complex queries.



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# File 'lib/prometheus/api_client/client.rb', line 117

def update_query(query, labels)
  query.sub(/(?<r>\[.+\])?(?<f>[)])?$/, "{#{labels}}\\k<r>\\k<f>")
end