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kwasniewkwasniew
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feat: read backup file and bootstrap for streaming (#255)
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4 files changed

+219
-21
lines changed

4 files changed

+219
-21
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‎lib/unleash/backup_file_reader.rb‎

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@@ -0,0 +1,24 @@
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require 'unleash/configuration'
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module Unleash
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class BackupFileReader
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def self.read!
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Unleash.logger.debug "read!()"
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backup_file = Unleash.configuration.backup_file
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return nil unless File.exist?(backup_file)
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File.read(backup_file)
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rescue IOError => e
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# :nocov:
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Unleash.logger.error "Unable to read the backup_file: #{e}"
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# :nocov:
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nil
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rescue StandardError => e
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# :nocov:
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Unleash.logger.error "Unable to extract valid data from backup_file. Exception thrown: #{e}"
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# :nocov:
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nil
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end
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end
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end

‎lib/unleash/streaming_client_executor.rb‎

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Original file line numberDiff line numberDiff line change
@@ -1,4 +1,6 @@
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require 'unleash/streaming_event_processor'
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require 'unleash/bootstrap/handler'
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require 'unleash/backup_file_reader'
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require 'unleash/util/event_source_wrapper'
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module Unleash
@@ -10,6 +12,20 @@ def initialize(name, engine)
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self.event_source = nil
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self.event_processor = Unleash::StreamingEventProcessor.new(engine)
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self.running = false
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begin
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# if bootstrap configuration is available, initialize. Otherwise read backup file
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if Unleash.configuration.use_bootstrap?
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bootstrap(engine)
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else
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read_backup_file!(engine)
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end
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rescue StandardError => e
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# fall back to reading the backup file
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Unleash.logger.warn "StreamingClientExecutor was unable to initialize, attempting to read from backup file."
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Unleash.logger.debug "Exception Caught: #{e}"
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read_backup_file!(engine)
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end
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end
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def run(&_block)
@@ -81,5 +97,18 @@ def handle_event(event)
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Unleash.logger.error "Streaming client #{self.name} threw exception #{e.class}: '#{e}'"
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Unleash.logger.debug "stacktrace: #{e.backtrace}"
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end
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def read_backup_file!(engine)
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backup_data = Unleash::BackupFileReader.read!
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engine.take_state(backup_data) if backup_data
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end
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def bootstrap(engine)
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bootstrap_payload = Unleash::Bootstrap::Handler.new(Unleash.configuration.bootstrap_config).retrieve_toggles
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engine.take_state(bootstrap_payload)
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# reset Unleash.configuration.bootstrap_data to free up memory, as we will never use it again
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Unleash.configuration.bootstrap_config = nil
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end
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end
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end

‎lib/unleash/toggle_fetcher.rb‎

Lines changed: 6 additions & 21 deletions
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,7 @@
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require 'unleash/configuration'
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require 'unleash/bootstrap/handler'
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require 'unleash/backup_file_writer'
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require 'unleash/backup_file_reader'
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require 'net/http'
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require 'json'
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require 'yggdrasil_engine'
@@ -24,10 +25,10 @@ def initialize(engine)
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fetch
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end
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rescue StandardError => e
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# fail back to reading the backup file
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# fall back to reading the backup file
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Unleash.logger.warn "ToggleFetcher was unable to fetch from the network, attempting to read from backup file."
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Unleash.logger.debug "Exception Caught: #{e}"
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read!
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read_backup_file!
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end
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# once initialized, somewhere else you will want to start a loop with fetch()
@@ -71,25 +72,9 @@ def update_engine_state!(toggle_data)
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Unleash.logger.error "Failed to hydrate state: #{e.backtrace}"
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end
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def read!
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Unleash.logger.debug "read!()"
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backup_file = Unleash.configuration.backup_file
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return nil unless File.exist?(backup_file)
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backup_data = File.read(backup_file)
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update_engine_state!(backup_data)
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rescue IOError => e
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# :nocov:
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Unleash.logger.error "Unable to read the backup_file: #{e}"
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# :nocov:
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rescue JSON::ParserError => e
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# :nocov:
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Unleash.logger.error "Unable to parse JSON from existing backup_file: #{e}"
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# :nocov:
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rescue StandardError => e
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# :nocov:
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Unleash.logger.error "Unable to extract valid data from backup_file. Exception thrown: #{e}"
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# :nocov:
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def read_backup_file!
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backup_data = Unleash::BackupFileReader.read!
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update_engine_state!(backup_data) if backup_data
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end
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def bootstrap

‎spec/unleash/streaming_client_executor_spec.rb‎

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RSpec.describe Unleash::StreamingClientExecutor do
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subject(:streaming_executor) { Unleash::StreamingClientExecutor.new(executor_name, engine) }
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unless RUBY_ENGINE == 'jruby'
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before do
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Unleash.configure do |config|
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config.url = 'http://streaming-test-url/'
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config.app_name = 'streaming-test-app'
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config.instance_id = 'rspec/streaming'
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config.disable_metrics = true
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config.experimental_mode = { type: 'streaming' }
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end
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WebMock.stub_request(:post, "http://streaming-test-url/client/register")
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.to_return(status: 200, body: "", headers: {})
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Unleash.logger = Unleash.configuration.logger
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end
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after do
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WebMock.reset!
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File.delete(Unleash.configuration.backup_file) if File.exist?(Unleash.configuration.backup_file)
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# Reset configuration to prevent interference with other tests
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Unleash.configuration.bootstrap_config = nil
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Unleash.configuration.experimental_mode = nil
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Unleash.configuration.disable_metrics = false
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end
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describe '.new' do
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let(:engine) { YggdrasilEngine.new }
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let(:executor_name) { 'streaming_client_executor_spec' }
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context 'when there are problems connecting to streaming endpoint' do
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let(:backup_toggles) do
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{
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version: 1,
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features: [
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{
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name: "backup-feature",
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description: "Feature from backup",
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enabled: true,
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strategies: [{
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name: "default"
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}]
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}
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]
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}
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end
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before do
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backup_file = Unleash.configuration.backup_file
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# manually create a stub cache on disk, so we can test that we read it correctly later.
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File.open(backup_file, "w") do |file|
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file.write(backup_toggles.to_json)
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end
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WebMock.stub_request(:get, "http://streaming-test-url/client/streaming")
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.to_return(status: 500, body: "Internal Server Error", headers: {})
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streaming_executor
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end
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it 'reads the backup file for values' do
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enabled = engine.enabled?('backup-feature', {})
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expect(enabled).to eq(true)
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end
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end
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context 'when bootstrap is configured' do
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let(:bootstrap_data) do
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{
74+
version: 1,
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features: [
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{
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name: "bootstrap-feature",
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enabled: true,
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strategies: [{ name: "default" }]
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}
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]
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}
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end
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let(:bootstrap_config) do
86+
Unleash::Bootstrap::Configuration.new({
87+
'data' => bootstrap_data.to_json
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})
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end
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before do
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Unleash.configuration.bootstrap_config = bootstrap_config
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WebMock.stub_request(:get, "http://streaming-test-url/client/streaming")
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.to_return(status: 200, body: "", headers: {})
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streaming_executor
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end
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after do
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Unleash.configuration.bootstrap_config = nil
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end
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it 'uses bootstrap data on initialization' do
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enabled = engine.enabled?('bootstrap-feature', {})
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expect(enabled).to eq(true)
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end
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it 'clears bootstrap config after use' do
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expect(Unleash.configuration.bootstrap_config).to be_nil
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end
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end
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context 'when bootstrap fails and backup file exists' do
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let(:invalid_bootstrap_config) do
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Unleash::Bootstrap::Configuration.new({
117+
'data' => 'invalid json'
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})
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end
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let(:fallback_toggles) do
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{
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version: 1,
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features: [
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{
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name: "fallback-feature",
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enabled: true,
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strategies: [{ name: "default" }]
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}
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]
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}
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end
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before do
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backup_file = Unleash.configuration.backup_file
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File.open(backup_file, "w") do |file|
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file.write(fallback_toggles.to_json)
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end
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Unleash.configuration.bootstrap_config = invalid_bootstrap_config
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WebMock.stub_request(:get, "http://streaming-test-url/client/streaming")
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.to_return(status: 500, body: "", headers: {})
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streaming_executor
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end
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after do
150+
Unleash.configuration.bootstrap_config = nil
151+
end
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it 'falls back to reading backup file when bootstrap fails' do
154+
enabled = engine.enabled?('fallback-feature', {})
155+
expect(enabled).to eq(true)
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end
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end
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end
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end
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end

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