fill the shared classes cache of openj9 even more

.dockerignore

@@ -3,4 +3,6 @@
 
 # allow only what we need
 !commafeed-server/target/commafeed.jar
+!commafeed-server/config.docker-warmup.yml
 !commafeed-server/config.yml.example
+

Dockerfile

@@ -5,12 +5,15 @@ EXPOSE 8082
 RUN mkdir -p /commafeed/data
 VOLUME /commafeed/data
 
+RUN apt update && apt install -y wait-for-it && apt clean
+
 ENV JAVA_TOOL_OPTIONS -Djava.net.preferIPv4Stack=true -Xtune:virtualized -Xminf0.05 -Xmaxf0.1
 
+COPY commafeed-server/config.docker-warmup.yml .
 COPY commafeed-server/config.yml.example config.yml
 COPY commafeed-server/target/commafeed.jar .
 
 # build openj9 shared classes cache to improve startup time
-RUN java -Xshareclasses -jar commafeed.jar
+RUN sh -c 'java -Xshareclasses -jar commafeed.jar server config.docker-warmup.yml &' ; wait-for-it -t 120 localhost:8088 -- pkill java ; rm -rf config.warmup.yml
 
 CMD ["java", "-Xshareclasses", "-jar", "commafeed.jar", "server", "config.yml"]

commafeed-server/config.docker-warmup.yml

@@ -0,0 +1,151 @@
+# CommaFeed settings
+# ------------------
+app:
+  # url used to access commafeed
+  publicUrl: http://localhost:8088/
+
+  # whether to expose a robots.txt file that disallows web crawlers and search engine indexers
+  hideFromWebCrawlers: true
+  
+  # whether to allow user registrations
+  allowRegistrations: true
+
+  # whether to enable strict password validation (1 uppercase char, 1 lowercase char, 1 digit, 1 special char)
+  strictPasswordPolicy: true
+  
+  # create a demo account the first time the app starts
+  createDemoAccount: true
+  
+  # put your google analytics tracking code here
+  googleAnalyticsTrackingCode:
+  
+  # put your google server key (used for youtube favicon fetching)
+  googleAuthKey:
+  
+  # number of http threads
+  backgroundThreads: 3
+  
+  # number of database updating threads
+  databaseUpdateThreads: 1
+
+  # rows to delete per query while cleaning up old entries
+  databaseCleanupBatchSize: 100
+
+  # settings for sending emails (password recovery)
+  smtpHost: localhost
+  smtpPort: 25
+  smtpTls: false
+  smtpUserName: user
+  smtpPassword: pass
+  smtpFromAddress:
+
+  # Graphite Metric settings
+  # Allows those who use Graphite to have CommaFeed send metrics for graphing (time in seconds)
+  graphiteEnabled: false
+  graphitePrefix: "test.commafeed"
+  graphiteHost: "localhost"
+  graphitePort: 2003
+  graphiteInterval: 60
+  
+  # whether this commafeed instance has a lot of feeds to refresh
+  # leave this to false in almost all cases
+  heavyLoad: false
+  
+  # minimum amount of time commafeed will wait before refreshing the same feed
+  refreshIntervalMinutes: 5
+
+  # if enabled, images in feed entries will be proxied through the server instead of accessed directly by the browser
+  # useful if commafeed is usually accessed through a restricting proxy  
+  imageProxyEnabled: true
+  
+  # database query timeout (in milliseconds), 0 to disable
+  queryTimeout: 0
+  
+  # time to keep unread statuses (in days), 0 to disable
+  keepStatusDays: 0
+  
+  # entries to keep per feed, old entries will be deleted, 0 to disable
+  maxFeedCapacity: 500
+
+  # entries older than this will be deleted, 0 to disable
+  maxEntriesAgeDays: 365
+
+  # limit the number of feeds a user can subscribe to, 0 to disable
+  maxFeedsPerUser: 0
+
+  # cache service to use, possible values are 'noop' and 'redis'
+  cache: noop
+  
+  # announcement string displayed on the main page
+  announcement:
+  
+  # user-agent string that will be used by the http client, leave empty for the default one
+  userAgent:
+
+  # enable websocket connection so the server can notify the web client that there are new entries for your feeds
+  websocketEnabled: true
+
+  # interval at which the client will send a ping message on the websocket to keep the connection alive
+  websocketPingInterval: 15m
+
+  # if websocket is disabled or the connection is lost, the client will reload the feed tree at this interval
+  treeReloadInterval: 30s
+
+# Database connection
+# -------------------  
+# for MariaDB
+# driverClass is org.mariadb.jdbc.Driver
+# url is jdbc:mariadb://localhost/commafeed?autoReconnect=true&failOverReadOnly=false&maxReconnects=20&rewriteBatchedStatements=true&timezone=UTC
+#
+# for MySQL
+# driverClass is com.mysql.cj.jdbc.Driver
+# url is jdbc:mysql://localhost/commafeed?autoReconnect=true&failOverReadOnly=false&maxReconnects=20&rewriteBatchedStatements=true&timezone=UTC
+#
+# for PostgreSQL
+# driverClass is org.postgresql.Driver
+# url is jdbc:postgresql://localhost:5432/commafeed
+
+database:
+  driverClass: org.h2.Driver
+  url: jdbc:h2:mem:commafeed
+  user: sa
+  password: sa
+  properties:
+    charSet: UTF-8
+  validationQuery: "/* CommaFeed Health Check */ SELECT 1"
+
+server:
+  applicationConnectors:
+    - type: http
+      port: 8088
+
+logging:
+  level: INFO
+  loggers:
+    com.commafeed: DEBUG
+    liquibase: INFO
+    org.hibernate.SQL: INFO # or ALL for sql debugging
+    org.hibernate.engine.internal.StatisticalLoggingSessionEventListener: WARN
+  appenders:
+    - type: console
+    - type: file
+      currentLogFilename: log/commafeed.log
+      threshold: ALL
+      archive: true
+      archivedLogFilenamePattern: log/commafeed-%d.log
+      archivedFileCount: 5
+      timeZone: UTC
+
+# Redis pool configuration
+# (only used if app.cache is 'redis')
+# -----------------------------------
+redis:
+  host: localhost
+  port: 6379
+  # username is only required when using ACLs
+  username:
+  password:
+  timeout: 2000
+  database: 0
+  maxTotal: 500
+