lttng-ctl: Expose sessiond cmd_clear_session command

[lttng-tools.git] / include / lttng / clear.h

diff --git a/include/lttng/clear.h b/include/lttng/clear.h
new file mode 100644 (file)
index 0000000..68c0cd4
--- /dev/null
+++ b/include/lttng/clear.h
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2019 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ * Copyright (C) 2019 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License, version 2.1 only,
+ * as published by the Free Software Foundation.
+ *
+ * This library is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef LTTNG_CLEAR_H
+#define LTTNG_CLEAR_H
+
+#include <lttng/lttng-error.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct lttng_clear_handle;
+
+/*
+ * Clear a tracing session.
+ *
+ * Clear the data buffers and trace data.
+ *
+ * For sessions saving trace data to disk and streaming over the network to a
+ * relay daemon, the buffers content and existing stream files are cleared when
+ * the clear command is issued.
+ *
+ * For snapshot sessions (flight recorder), only the buffer content is cleared.
+ * Prior snapshots are individually recorded to disk, and are therefore
+ * untouched by this "clear" command.
+ *
+ * For live sessions streaming over network to a relay daemon, the buffers
+ * will be cleared and the files on the relay daemon side will be cleared as
+ * well. However, any active live trace viewer currently reading an existing
+ * trace packet will be able to proceed to read that packet entirely before
+ * skipping over cleared stream data.
+ *
+ * The clear command guarantees that no trace data produced before this function
+ * is called will be present in the resulting trace.
+ *
+ * Trace data produced between the moment this function is called and when it
+ * returns might be present in the resulting trace.
+ *
+ * Provides an lttng_clear_handle which can be used to wait for the completion
+ * of the session's clear.
+ *
+ * Return LTTNG_OK on success else a negative LTTng error code. The returned
+ * handle is owned by the caller and must be free'd using
+ * lttng_clear_handle_destroy().
+ *
+ * Important error codes:
+ *    LTTNG_ERR_CLEAR_RELAY_DISALLOWED
+ *    LTTNG_ERR_CLEAR_NOT_AVAILABLE_RELAY
+ *    LTTNG_ERR_CLEAR_FAIL_CONSUMER
+*/
+extern enum lttng_error_code lttng_clear_session(const char *session_name,
+               struct lttng_clear_handle **handle);
+
+#endif /* LTTNG_CLEAR_H */