compress previous log file on startup (#16674)

2 files changed, 34 insertions, 2 deletions

diff --git a/jdisc_http_service/src/main/java/com/yahoo/container/logging/LogFileHandler.java b/jdisc_http_service/src/main/java/com/yahoo/container/logging/LogFileHandler.java
index 3e257813b5e..0f2a9e42eb8 100644
--- a/jdisc_http_service/src/main/java/com/yahoo/container/logging/LogFileHandler.java
+++ b/jdisc_http_service/src/main/java/com/yahoo/container/logging/LogFileHandler.java
@@ -366,6 +366,7 @@ class LogFileHandler <LOGTYPE> {
                 throw new RuntimeException("Couldn't open log file '" + fileName + "'", e);
             }
 
+            if(oldFileName == null) oldFileName = getOldFileNameFromSymlink(); // To compress previous file, if so configured
             createSymlinkToCurrentFile();
 
             nextRotationTime = 0; //figure it out later (lazy evaluation)
@@ -465,6 +466,15 @@ class LogFileHandler <LOGTYPE> {
             }
         }
 
+        private String getOldFileNameFromSymlink() {
+            if(symlinkName == null) return null;
+            try {
+                return Paths.get(fileName).resolveSibling(symlinkName).toRealPath().toString();
+            } catch (IOException e) {
+                return null;
+            }
+        }
+
         private static final long lengthOfDayMillis = 24 * 60 * 60 * 1000;
         private static long timeOfDayMillis(long time) {
             return time % lengthOfDayMillis;
@@ -475,8 +485,6 @@ class LogFileHandler <LOGTYPE> {
     private static class Operation<LOGTYPE> {
         enum Type {log, flush, close, rotate}
 
-        ;
-
         final Type type;
 
         final Optional<LOGTYPE> log;
diff --git a/jdisc_http_service/src/test/java/com/yahoo/container/logging/LogFileHandlerTestCase.java b/jdisc_http_service/src/test/java/com/yahoo/container/logging/LogFileHandlerTestCase.java
index 8f78530327e..dad8f5e3f90 100644
--- a/jdisc_http_service/src/test/java/com/yahoo/container/logging/LogFileHandlerTestCase.java
+++ b/jdisc_http_service/src/test/java/com/yahoo/container/logging/LogFileHandlerTestCase.java
@@ -125,6 +125,30 @@ public class LogFileHandlerTestCase {
     }
 
     @Test(timeout = /*5 minutes*/300_000)
+    public void compresses_previous_log_file() throws InterruptedException, IOException {
+        File root = temporaryFolder.newFolder("compressespreviouslogfile");
+        LogFileHandler<String> firstHandler = new LogFileHandler<>(
+                Compression.ZSTD, root.getAbsolutePath() + "/compressespreviouslogfile.%Y%m%d%H%M%S%s", new long[]{0}, "symlink", 2048, "thread-name", new StringLogWriter());
+        firstHandler.publishAndWait("test");
+        firstHandler.shutdown();
+
+        assertThat(Files.size(Paths.get(firstHandler.getFileName()))).isEqualTo(5);
+        assertThat(root.toPath().resolve("symlink").toRealPath().toString()).isEqualTo(firstHandler.getFileName());
+
+        LogFileHandler<String> secondHandler = new LogFileHandler<>(
+                Compression.ZSTD, root.getAbsolutePath() + "/compressespreviouslogfile.%Y%m%d%H%M%S%s", new long[]{0}, "symlink", 2048, "thread-name", new StringLogWriter());
+        secondHandler.publishAndWait("test");
+        secondHandler.rotateNow();
+
+        assertThat(root.toPath().resolve("symlink").toRealPath().toString()).isEqualTo(secondHandler.getFileName());
+
+        while (Files.exists(root.toPath().resolve(firstHandler.getFileName()))) Thread.sleep(1);
+
+        assertThat(Files.exists(Paths.get(firstHandler.getFileName() + ".zst"))).isTrue();
+        secondHandler.shutdown();
+    }
+
+    @Test(timeout = /*5 minutes*/300_000)
     public void testcompression_gzip() throws InterruptedException, IOException {
         testcompression(
                 Compression.GZIP, "gz",