Do not raise on some github exceptions

To reduce sidekiq error rates due to client errors from GitHub imports,
user mistakes on inputed data, like invalid credentials or URLs, won't
raise exceptions anymore. Instead, the error will be logged.

Other exceptions will continue to be raise.

app/services/import/github_service.rb

@@ -10,15 +10,26 @@ module Import
         return error(_('This namespace has already been taken! Please choose another one.'), :unprocessable_entity)
       end
 
-      project = Gitlab::LegacyGithubImport::ProjectCreator
-                  .new(repo, project_name, target_namespace, current_user, access_params, type: provider)
-                  .execute(extra_project_attrs)
+      project = create_project(access_params, provider)
 
       if project.persisted?
         success(project)
       else
         error(project_save_error(project), :unprocessable_entity)
       end
+    rescue Octokit::Error => e
+      log_error(e)
+    end
+
+    def create_project(access_params, provider)
+      Gitlab::LegacyGithubImport::ProjectCreator.new(
+        repo,
+        project_name,
+        target_namespace,
+        current_user,
+        access_params,
+        type: provider
+      ).execute(extra_project_attrs)
     end
 
     def repo
@@ -44,6 +55,18 @@ module Import
     def authorized?
       can?(current_user, :create_projects, target_namespace)
     end
+
+    private
+
+    def log_error(exception)
+      Gitlab::Import::Logger.error(
+        message: 'Import failed due to a GitHub error',
+        status: exception.response_status,
+        error: exception.response_body
+      )
+
+      error(_('Import failed due to a GitHub error: %{original}') % { original: exception.response_body }, :unprocessable_entity)
+    end
   end
 end
 

locale/gitlab.pot

@@ -11622,6 +11622,9 @@ msgstr ""
 msgid "Import an exported GitLab project"
 msgstr ""
 
+msgid "Import failed due to a GitHub error: %{original}"
+msgstr ""
+
 msgid "Import from"
 msgstr ""
 

spec/services/import/github_service_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Import::GithubService do
+  let_it_be(:user) { create(:user) }
+  let_it_be(:token) { 'complex-token' }
+  let_it_be(:access_params) { { github_access_token: 'github-complex-token' } }
+  let_it_be(:client) { Gitlab::LegacyGithubImport::Client.new(token) }
+  let_it_be(:params) { { repo_id: 123, new_name: 'new_repo', target_namespace: 'root' } }
+
+  let(:subject) { described_class.new(client, user, params) }
+
+  before do
+    allow(subject).to receive(:authorized?).and_return(true)
+  end
+
+  context 'do not raise an exception on input error' do
+    let(:exception) { Octokit::ClientError.new(status: 404, body: 'Not Found') }
+
+    before do
+      expect(client).to receive(:repo).and_raise(exception)
+    end
+
+    it 'logs the original error' do
+      expect(Gitlab::Import::Logger).to receive(:error).with({
+        message: 'Import failed due to a GitHub error',
+        status: 404,
+        error: 'Not Found'
+      }).and_call_original
+
+      subject.execute(access_params, :github)
+    end
+
+    it 'returns an error' do
+      result = subject.execute(access_params, :github)
+
+      expect(result).to include(
+        message: 'Import failed due to a GitHub error: Not Found',
+        status: :error,
+        http_status: :unprocessable_entity
+      )
+    end
+  end
+
+  it 'raises an exception for unknown error causes' do
+    exception = StandardError.new('Not Implemented')
+
+    expect(client).to receive(:repo).and_raise(exception)
+
+    expect(Gitlab::Import::Logger).not_to receive(:error)
+
+    expect { subject.execute(access_params, :github) }.to raise_error(exception)
+  end
+end