allow to use read-only configuration in Docker

fixes #3531

Author: Vladimir Kotal

docker/README.md

@@ -83,6 +83,7 @@ The volume mounted to `/opengrok/src` should contain the projects you want to ma
 `AVOID_PROJECTS` | empty | run in project less configuration. Set to non empty value disables projects.
 `REST_PORT` | 5000 | TCP port where simple REST app listens for GET requests on `/reindex` to trigger manual reindex.
 `REST_TOKEN` | None | if set, the REST app will require this token as Bearer token in order to trigger reindex.
+`READONLY_CONFIG_FILE` | None | if set, the configuration will be merged with configuration from this file. This is run when the container starts.
 
 To specify environment variable for `docker run`, use the `-e` option, e.g. `-e SYNC_PERIOD_MINUTES=30`
 

docker/start.py

@@ -26,6 +26,7 @@
 import multiprocessing
 import shutil
 import subprocess
+import tempfile
 import threading
 import time
 from pathlib import Path
@@ -39,6 +40,7 @@
 from opengrok_tools.deploy import deploy_war
 from opengrok_tools.utils.indexer import Indexer
 from opengrok_tools.sync import do_sync
+from opengrok_tools.config_merge import merge_config_files
 from opengrok_tools.utils.opengrok import list_projects, \
     add_project, delete_project, get_configuration, set_config_value
 from opengrok_tools.utils.readconfig import read_config
@@ -444,6 +446,28 @@ def main():
             os.path.getsize(OPENGROK_CONFIG_FILE) == 0:
         create_bare_config(logger, extra_indexer_options.split())
 
+    #
+    # If there is read-only configuration file, merge it with current
+    # configuration.
+    #
+    read_only_config_file = os.environ.get('READONLY_CONFIG_FILE')
+    if read_only_config_file and os.path.exists(read_only_config_file):
+        logger.info('Merging read-only configuration from \'{}\' with current '
+                    'configuration in \'{}\''.format(read_only_config_file,
+                                                     OPENGROK_CONFIG_FILE))
+        out_file = None
+        with tempfile.NamedTemporaryFile(mode='w+', delete=False,
+                                         prefix='merged_config') as tmp_out:
+            merge_config_files(read_only_config_file, OPENGROK_CONFIG_FILE,
+                               tmp_out, jar=OPENGROK_JAR, loglevel=log_level)
+            out_file = tmp_out.name
+
+        if out_file and os.path.getsize(out_file) > 0:
+            shutil.move(tmp_out.name, OPENGROK_CONFIG_FILE)
+        else:
+            logger.warning('Failed to merge read-only configuration, '
+                           'leaving the original in place')
+
     if use_projects:
         num_workers = get_num_from_env(logger, 'WORKERS',
                                        multiprocessing.cpu_count())

tools/src/main/python/opengrok_tools/config_merge.py

@@ -18,7 +18,7 @@
 # CDDL HEADER END
 
 #
-# Copyright (c) 2017, 2018, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2017, 2021, Oracle and/or its affiliates. All rights reserved.
 #
 
 import argparse
@@ -37,34 +37,55 @@
 """
 
 
-def main():
-    parser = argparse.ArgumentParser(description='Java wrapper for project '
-                                                 'configuration merging',
-                                     parents=[get_java_parser()])
+def merge_config_files(read_only, current, out_file, jar,
+                       loglevel=logging.INFO):
+
+    return config_merge_wrapper([read_only, current], jar=jar,
+                                out_file=out_file, loglevel=loglevel)
 
-    try:
-        args = parser.parse_args()
-    except ValueError as e:
-        fatal(e)
+
+def config_merge_wrapper(options, loglevel=logging.INFO,
+                         jar=None, java=None, java_opts=None,
+                         doprint=False, out_file=None):
 
     # Avoid using utils.log.get_console_level() since the stdout of the program
     # is interpreted as data.
     logger = logging.getLogger(__name__)
-    logger.setLevel(args.loglevel)
+    logger.setLevel(loglevel)
 
-    cmd = Java(args.options, classpath=args.jar, java=args.java,
-               java_opts=args.java_opts, redirect_stderr=False,
+    cmd = Java(options, classpath=jar, java=java,
+               java_opts=java_opts, redirect_stderr=False,
                main_class='org.opengrok.indexer.configuration.ConfigMerge',
-               logger=logger, doprint=args.doprint)
+               logger=logger, doprint=doprint)
     cmd.execute()
     ret = cmd.getretcode()
     if ret is None or ret != SUCCESS_EXITVAL:
         logger.error(cmd.geterroutput())
         logger.error("command failed (return code {})".format(ret))
-        sys.exit(FAILURE_EXITVAL)
+        return FAILURE_EXITVAL
     else:
-        print(cmd.getoutputstr())
+        if out_file:
+            out_file.write(cmd.getoutputstr())
+        else:
+            print(cmd.getoutputstr())
+
+    return SUCCESS_EXITVAL
+
+
+def main():
+    parser = argparse.ArgumentParser(description='Java wrapper for project '
+                                                 'configuration merging',
+                                     parents=[get_java_parser()])
+
+    try:
+        args = parser.parse_args()
+    except ValueError as e:
+        fatal(e)
+
+    return config_merge_wrapper(options=args.options, loglevel=args.loglevel,
+                                jar=args.jar, java=args.java,
+                                java_opts=args.java_opts, doprint=args.doprint)
 
 
 if __name__ == '__main__':
-    main()
+    sys.exit(main())

tools/src/main/python/opengrok_tools/utils/java.py

@@ -18,14 +18,16 @@
 # CDDL HEADER END
 
 #
-# Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2008, 2021, Oracle and/or its affiliates. All rights reserved.
 # Portions Copyright (c) 2017-2018, Chris Fraire <[email protected]>.
 #
 
+import os
 import platform
+import shutil
+
 from .command import Command
 from .utils import is_exe
-import os
 
 
 class Java(Command):
@@ -105,4 +107,9 @@ def FindJava(self, logger):
                 if os.path.isdir(java_home):
                     java = os.path.join(java_home, 'bin', 'java')
 
+        if not java:
+            logger.debug("Could not detemine java executable using standard "
+                         "means, trying system path")
+            java = shutil.which('java')
+
         return java