Add option to log to a file

diff --git a/org.argeo.init/src/org/argeo/init/logging/ThinLogging.java b/org.argeo.init/src/org/argeo/init/logging/ThinLogging.java
index c2ce215288171bf94543a5fd0a949013b25b6bf2..ff602ad51a7c06abe532fc5af3111f9c18870a93 100644 (file)
--- a/org.argeo.init/src/org/argeo/init/logging/ThinLogging.java
+++ b/org.argeo.init/src/org/argeo/init/logging/ThinLogging.java
@@ -1,9 +1,14 @@
 package org.argeo.init.logging;
 
+import java.io.IOException;
 import java.io.PrintStream;
 import java.io.Serializable;
 import java.lang.System.Logger;
 import java.lang.System.Logger.Level;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.text.MessageFormat;
 import java.time.Instant;
 import java.util.Collections;
@@ -43,10 +48,12 @@ class ThinLogging implements Consumer<Map<String, Object>> {
         */
        final static String PROP_ARGEO_LOGGING_SYNCHRONOUS = "argeo.logging.synchronous";
        /**
-        * Whether to enable jounrald compatible output, either: auto (default), true,
+        * Whether to enable journald compatible output, either: auto (default), true,
         * or false.
         */
        final static String PROP_ARGEO_LOGGING_JOURNALD = "argeo.logging.journald";
+       /** A file to which additionally write log entries. */
+       final static String PROP_ARGEO_LOGGING_FILE = "argeo.logging.file";
        /**
         * The level from which call location (that is, line number in Java code) will
         * be searched (default is WARNING)
@@ -67,6 +74,7 @@ class ThinLogging implements Consumer<Map<String, Object>> {
 
        private final LogEntryPublisher publisher;
        private PrintStreamSubscriber synchronousSubscriber;
+       private PrintStream fileOut;
 
        private final boolean journald;
        private final Level callLocationLevel;
@@ -82,6 +90,21 @@ class ThinLogging implements Consumer<Map<String, Object>> {
                        PrintStreamSubscriber subscriber = new PrintStreamSubscriber();
                        publisher = new LogEntryPublisher();
                        publisher.subscribe(subscriber);
+                       String logFileStr = System.getProperty(PROP_ARGEO_LOGGING_FILE);
+                       if (logFileStr != null) {
+                               Path logFilePath = Paths.get(logFileStr);
+                               if (!Files.exists(logFilePath.getParent())) {
+                                       System.err.println("Parent directory of " + logFilePath + " does not exist");
+                               } else {
+                                       try {
+                                               fileOut = new PrintStream(Files.newOutputStream(logFilePath), true, StandardCharsets.UTF_8);
+                                               publisher.subscribe(new PrintStreamSubscriber(fileOut, fileOut));
+                                       } catch (IOException e) {
+                                               System.err.println("Cannot write log to " + logFilePath);
+                                               e.printStackTrace();
+                                       }
+                               }
+                       }
                }
                Runtime.getRuntime().addShutdownHook(new Thread(() -> close(), "Log shutdown"));
 
@@ -147,6 +170,14 @@ class ThinLogging implements Consumer<Map<String, Object>> {
                                // silent
                        }
                }
+
+               if (fileOut != null) {
+                       try {
+                               fileOut.close();
+                       } catch (Exception e) {
+                               // silent
+                       }
+               }
        }
 
        private Level computeApplicableLevel(String name) {