Merge pull request #434 from retentionscience/aw/exp-backoff

On OctoKit::Forbidden error: retry with exponential backoff

github_changelog_generator.gemspec

@@ -29,4 +29,5 @@ Gem::Specification.new do |spec|
   spec.add_runtime_dependency("octokit", ["~> 4.0"])
   spec.add_runtime_dependency("faraday-http-cache")
   spec.add_runtime_dependency("activesupport")
+  spec.add_runtime_dependency("retriable", ["~> 2.1"])
 end

lib/github_changelog_generator/octo_fetcher.rb

@@ -1,4 +1,5 @@
 # frozen_string_literal: true
+require "retriable"
 module GitHubChangelogGenerator
   # A Fetcher responsible for all requests to GitHub and all basic manipulation with related data
   # (such as filtering, validating, e.t.c)
@@ -8,6 +9,7 @@ module GitHubChangelogGenerator
   class OctoFetcher
     PER_PAGE_NUMBER   = 100
     MAX_THREAD_NUMBER = 25
+    MAX_FORBIDDEN_RETRIES = 100
     CHANGELOG_GITHUB_TOKEN = "CHANGELOG_GITHUB_TOKEN"
     GH_RATE_LIMIT_EXCEEDED_MSG = "Warning: Can't finish operation: GitHub API rate limit exceeded, change log may be " \
     "missing some issues. You can limit the number of issues fetched using the `--max-issues NUM` argument."
@@ -280,17 +282,45 @@ Make sure, that you push tags to remote repo via 'git push --tags'"
     #
     # @return [Object] returns exactly the same, what you put in the block, but wrap it with begin-rescue block
     def check_github_response
-      begin
-        value = yield
-      rescue Octokit::Unauthorized => e
-        Helper.log.error e.message
-        abort "Error: wrong GitHub token"
-      rescue Octokit::Forbidden => e
-        Helper.log.warn e.message
+      Retriable.retriable(retry_options) do
+        yield
+      end
+
+    rescue Octokit::Forbidden => e
+      Helper.log.error("#{e.class}: #{e.message}")
+      sys_abort("Exceeded retry limit")
+    rescue Octokit::Unauthorized => e
+      Helper.log.error("#{e.class}: #{e.message}")
+      sys_abort("Error: wrong GitHub token")
+    end
+
+    # Exponential backoff
+    def retry_options
+      {
+        on: [Octokit::Forbidden],
+        tries: MAX_FORBIDDEN_RETRIES,
+        base_interval: sleep_base_interval,
+        multiplier: 1.0,
+        rand_factor: 0.0,
+        on_retry: retry_callback
+      }
+    end
+
+    def sleep_base_interval
+      1.0
+    end
+
+    def retry_callback
+      proc do |exception, try, elapsed_time, next_interval|
+        Helper.log.warn("RETRY - #{exception.class}: '#{exception.message}'")
+        Helper.log.warn("#{try} tries in #{elapsed_time} seconds and #{next_interval} seconds until the next try")
         Helper.log.warn GH_RATE_LIMIT_EXCEEDED_MSG
         Helper.log.warn @client.rate_limit
       end
-      value
+    end
+
+    def sys_abort(msg)
+      abort(msg)
     end
 
     # Print specified line on the same string

lib/github_changelog_generator/parser.rb

@@ -42,7 +42,7 @@ module GitHubChangelogGenerator
 
     # setup parsing options
     def self.setup_parser(options)
-      parser = OptionParser.new do |opts|
+      parser = OptionParser.new do |opts| # rubocop:disable Metrics/BlockLength
         opts.banner = "Usage: github_changelog_generator [options]"
         opts.on("-u", "--user [USER]", "Username of the owner of target GitHub repo") do |last|
           options[:user] = last

spec/unit/octo_fetcher_spec.rb

@@ -12,6 +12,31 @@ describe GitHubChangelogGenerator::OctoFetcher do
 
   let(:fetcher) { GitHubChangelogGenerator::OctoFetcher.new(options) }
 
+  describe "#check_github_response" do
+    context "when returns successfully" do
+      it "returns block value" do
+        expect(fetcher.send(:check_github_response) { 1 + 1 }).to eq(2)
+      end
+    end
+
+    context "when raises Octokit::Unauthorized" do
+      it "aborts" do
+        expect(fetcher).to receive(:sys_abort).with("Error: wrong GitHub token")
+        fetcher.send(:check_github_response) { raise(Octokit::Unauthorized) }
+      end
+    end
+
+    context "when raises Octokit::Forbidden" do
+      it "sleeps and retries and then aborts" do
+        retry_limit = GitHubChangelogGenerator::OctoFetcher::MAX_FORBIDDEN_RETRIES - 1
+        allow(fetcher).to receive(:sleep_base_interval).exactly(retry_limit).times.and_return(0)
+
+        expect(fetcher).to receive(:sys_abort).with("Exceeded retry limit")
+        fetcher.send(:check_github_response) { raise(Octokit::Forbidden) }
+      end
+    end
+  end
+
   describe "#fetch_github_token" do
     token = GitHubChangelogGenerator::OctoFetcher::CHANGELOG_GITHUB_TOKEN
     context "when token in ENV exist" do