1 files changed, 48 insertions, 0 deletions
diff --git a/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/component/TaskContext.java b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/component/TaskContext.java
new file mode 100644
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+++ b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/component/TaskContext.java
@@ -0,0 +1,48 @@
+// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.hosted.node.admin.component;
+
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public interface TaskContext {
+    /**
+     * Record a system modification. IdempotentTask is supposed to converge the system (files,
+     * directory permission, iptable rules, etc) to some wanted state. It is especially important
+     * to produce a truthful log of system changes to understand what may or may not be going on.
+     *
+     * All tasks should:
+     *  1. Record any and all modifications to the system
+     *  2. Avoid recording system interactions that does not actually change the system.
+     *  3. Record system modifications as early as possible and preferably before they are
+     *     performed (sometimes this is not possible).
+     *
+     * @param logger Used to log the modification to help locate the source of the modification.
+     * @param message Description of the modification, e.g. "Changing owner of /foo from alice
+     *                to bob".
+     */
+    void recordSystemModification(Logger logger, String message);
+    default void recordSystemModification(Logger logger, String messageFormat, Object... args) {
+        recordSystemModification(logger, String.format(messageFormat, args));
+    }
+
+    /**
+     * Log message at Level.INFO, scoped to denote the current task. The message may
+     * also be directed to status pages or similar.
+     *
+     * Please do not call this too many times as that spams the log. Typically a task may call
+     * this zero times, or up to a few times.
+     *
+     * Do not log a message that is also recorded with recordSystemModification.
+     */
+    default void log(Logger logger, String message) {
+        log(logger, Level.INFO, message);
+    }
+
+    default void log(Logger logger, String messageFormat, Object... args) {
+        log(logger, String.format(messageFormat, args));
+    }
+
+    void log(Logger logger, Level level, String message);
+
+    void log(Logger logger, Level level, String message, Throwable throwable);
+}