Query apm server for version and details about supported features

CHANGELOG.asciidoc

@@ -42,6 +42,7 @@ endif::[]
 ===== Added
 
 - Added transaction_name to reported error to allow grouping by transaction name {pull}1267[#1267]
+- Added ability to query server for version (useful in the future) {pull}1278[#1278]
 
 ===== Changed
 

lib/elastic_apm/config.rb

@@ -25,6 +25,7 @@
 require 'elastic_apm/config/regexp_list'
 require 'elastic_apm/config/wildcard_pattern_list'
 require 'elastic_apm/deprecations'
+require 'elastic_apm/config/server_info'
 
 module ElasticAPM
  # @api private
@@ -243,6 +244,10 @@ def inspect
  super.split.first + '>'
  end
 
+ def version
+ @version ||= ServerInfo.new(self).version
+ end
+
  private
 
  def load_config_file

lib/elastic_apm/config/server_info.rb

@@ -0,0 +1,45 @@
+# Licensed to Elasticsearch B.V. under one or more contributor
+# license agreements. See the NOTICE file distributed with
+# this work for additional information regarding copyright
+# ownership. Elasticsearch B.V. licenses this file to you under
+# the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied. See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+# frozen_string_literal: true
+
+module ElasticAPM
+ class Config
+ # @api private
+ class ServerInfo
+ attr_reader :payload, :config, :http
+
+ def initialize(config)
+ @config = config
+ @http = Transport::Connection::Http.new(config)
+ end
+
+ def execute
+ resp = http.get(config.server_url)
+ @payload = JSON.parse(resp.body)
+ rescue
+ @payload = {"version" => nil}
+ end
+
+ def version
+ execute unless payload
+ payload["version"]
+ end
+ end
+ end
+end
+

spec/elastic_apm/config_spec.rb

@@ -294,5 +294,19 @@ module ElasticAPM
  expect(subject.logger.level).to eq(Logger::INFO)
  end
  end
+
+ describe "#version" do
+ it "has no version if the server does not respond" do
+ WebMock.stub_request(:get, "http://localhost:8200/")
+ .to_return(status: 404, body: "")
+ expect(Config.new.version).to be_nil
+ end
+
+ it "returns the version from the server" do
+ WebMock.stub_request(:get, "http://localhost:8200/")
+ .to_return(status: 200, body: '{"version": 8.0}')
+ expect(Config.new.version).to eq 8.0
+ end
+ end
  end
 end

spec/support/mock_intake.rb

@@ -68,6 +68,10 @@ def stub!
  :get, %r{^http://localhost:8200/config/v1/agents/?$}
  ).to_return(body: '{}')
 
+ @server_version_stub =
+ WebMock.stub_request(:get, %r{^http://localhost:8200/$}).
+ to_return(body: '{"version":8.0}')
+
  @request_stub =
  WebMock.stub_request(
  :post, %r{^http://localhost:8200/intake/v2/events/?$}
@@ -95,6 +99,7 @@ def reset!
  @request_stub = nil
  @central_config_stub = nil
  @cloud_provider_stubs = nil
+ @server_version_stub = nil
  end
 
  def call(env)

spec/support/with_agent.rb

@@ -28,11 +28,16 @@ def with_agent(klass: ElasticAPM, args: [], **config)
  :get, %r{^http://localhost:8200/config/v1/agents/?$}
  ).to_return(body: '{}')
 
+ @server_version_stub =
+ WebMock.stub_request(:get, %r{^http://localhost:8200/$}).
+ to_return(body: '{"version":8.0}')
+
  klass.start(*args, **config)
  yield
  ensure
  ElasticAPM.stop
 
  @central_config_stub = nil
+ @server_version_stub = nil
  end
 end