Add db_operation_timeout BOSH property for locket (#1141)

Companion change for cloudfoundry/locket#40 (context detach fix).

Adds diego.locket.sql.db_operation_timeout property (default: 10s)
that controls the independent timeout for handler-initiated DB
operations. This allows operators to tune the timeout without
recompiling the locket binary.

Also adds locket_template_spec.rb covering timeout configuration
rendering — no such spec existed previously.

Author: vlast3k

jobs/locket/spec

@@ -64,9 +64,12 @@ properties:
   diego.locket.sql.db_read_timeout: 
     description: "Timeout in seconds for a db client to wait for data to be received from the server"
     default: "60"
-  diego.locket.sql.db_write_timeout: 
+  diego.locket.sql.db_write_timeout:
     description: "Timeout in seconds for a db client to wait for data to be sent to the server"
     default: "60"
+  diego.locket.sql.db_operation_timeout:
+    description: "Timeout in seconds for handler-initiated DB operations (Lock, Release, Fetch). Independent of gRPC client deadline."
+    default: "10"
   diego.locket.sql.require_ssl:
     description: "Whether to require SSL for Locket communication to the SQL backend"
     default: false

jobs/locket/templates/locket.json.erb

@@ -80,6 +80,9 @@ end
     config[:db_write_timeout] = "#{value}s" # add time unit
   end
 
+  if_p("diego.locket.sql.db_operation_timeout") do |value|
+    config[:db_operation_timeout] = "#{value}s" # add time unit
+    
   if_p("diego.locket.health_check_timeout") do |value|
     config[:health_check_timeout] = "#{value}s" # add time unit
   end

spec/locket_template_spec.rb

@@ -0,0 +1,95 @@
+# frozen_string_literal: true
+
+require 'rspec'
+require 'json'
+require 'bosh/template/test'
+
+describe 'locket' do
+  let(:release_path) { File.join(File.dirname(__FILE__), '..') }
+  let(:release) { Bosh::Template::Test::ReleaseDir.new(release_path) }
+  let(:job) { release.job('locket') }
+
+  describe 'locket.json.erb' do
+    let(:deployment_manifest_fragment) do
+      {
+        'diego' => {
+          'locket' => {
+            'listen_addr' => '0.0.0.0:8891',
+            'debug_addr' => '127.0.0.1:17018',
+            'log_level' => 'info',
+            'sql' => {
+              'db_host' => 'sql-db.service.cf.internal',
+              'db_port' => 5432,
+              'db_schema' => 'locket',
+              'db_username' => 'locket',
+              'db_password' => 'locket_pw',
+              'db_driver' => 'postgres',
+              'require_ssl' => false
+            }
+          }
+        },
+        'database' => {
+          'max_open_connections' => 200,
+          'tls' => {
+            'enable_identity_verification' => true
+          }
+        },
+        'tls' => {
+          'ca_cert' => 'CA CERT',
+          'cert' => 'SERVER CERT',
+          'key' => 'SERVER KEY'
+        },
+        'loggregator' => {
+          'v2_api_port' => 3458,
+          'ca_cert' => 'LOGGREGATOR CA',
+          'cert' => 'LOGGREGATOR CERT',
+          'key' => 'LOGGREGATOR KEY'
+        },
+        'set_kernel_parameters' => true
+      }
+    end
+
+    let(:template) { job.template('config/locket.json') }
+    let(:rendered_template) { template.render(deployment_manifest_fragment) }
+
+    describe 'Database timeout configurations' do
+      it 'includes db_operation_timeout when specified' do
+        deployment_manifest_fragment['diego']['locket']['sql']['db_operation_timeout'] = '15'
+        rendered_template_json = JSON.parse(rendered_template)
+        expect(rendered_template_json['db_operation_timeout']).to eq('15s')
+      end
+
+      it 'uses default db_operation_timeout of 10s when not overridden' do
+        rendered_template_json = JSON.parse(rendered_template)
+        expect(rendered_template_json['db_operation_timeout']).to eq('10s')
+      end
+
+      it 'includes db_connection_timeout when specified' do
+        deployment_manifest_fragment['diego']['locket']['sql']['db_connection_timeout'] = '30'
+        rendered_template_json = JSON.parse(rendered_template)
+        expect(rendered_template_json['db_connection_timeout']).to eq('30s')
+      end
+
+      it 'includes db_read_timeout when specified' do
+        deployment_manifest_fragment['diego']['locket']['sql']['db_read_timeout'] = '60'
+        rendered_template_json = JSON.parse(rendered_template)
+        expect(rendered_template_json['db_read_timeout']).to eq('60s')
+      end
+
+      it 'includes db_write_timeout when specified' do
+        deployment_manifest_fragment['diego']['locket']['sql']['db_write_timeout'] = '60'
+        rendered_template_json = JSON.parse(rendered_template)
+        expect(rendered_template_json['db_write_timeout']).to eq('60s')
+      end
+    end
+
+    describe 'basic configuration' do
+      it 'renders a valid JSON config' do
+        rendered_template_json = JSON.parse(rendered_template)
+        expect(rendered_template_json['listen_address']).to eq('0.0.0.0:8891')
+        expect(rendered_template_json['database_driver']).to eq('postgres')
+        expect(rendered_template_json['max_open_database_connections']).to eq(200)
+      end
+    end
+  end
+end