mgmtd: Add MGMT Transaction Framework

This commit introduces the MGMT Transaction framework that takes
management requests from one (or more) frontend client sessions,
translates them into transactions and drives them to completion
in co-oridination with one (or more) backend client daemons
involved in the request.

This commit includes the following functionalities in the changeset:
1. Introduces the actual Transaction module. Commands added related to
   transaction are:
   a. show mgmt transaction all
2. Adds support for commit rollback feature which stores upto the 10
   commit buffers. Each commit has a commit-id which can be used to
   rollback to the exact configuration state.
   Commands supported for this feature are:
   a. show mgmt commit-history
   b. mgmt rollback commit-id COMMIT_ID
3. Add hidden commands to enable record various performance metrics:
   a. mgmt performance-measurement
   b. mgmt reset-statistic

Co-authored-by: Pushpasis Sarkar <pushpasis@gmail.com>
Co-authored-by: Abhinay Ramesh <rabhinay@vmware.com>
Co-authored-by: Ujwal P <ujwalp@vmware.com>
Signed-off-by: Yash Ranjan <ranjany@vmware.com>

1 files changed, 44 insertions, 17 deletions

diff --git a/mgmtd/mgmt_ds.c b/mgmtd/mgmt_ds.c
index 2f4e7f8492..1724afb182 100644
--- a/mgmtd/mgmt_ds.c
+++ b/mgmtd/mgmt_ds.c
@@ -11,6 +11,8 @@
 #include "mgmtd/mgmt.h"
 #include "mgmtd/mgmt_memory.h"
 #include "mgmtd/mgmt_ds.h"
+#include "mgmtd/mgmt_history.h"
+#include "mgmtd/mgmt_txn.h"
 #include "libyang/libyang.h"
 
 #ifdef REDIRECT_DEBUG_TO_STDERR
@@ -22,7 +24,7 @@
 #define MGMTD_DS_DBG(fmt, ...)                                                 \
 	do {                                                                   \
 		if (mgmt_debug_ds)                                             \
-			zlog_debug("%s: " fmt, __func__, ##__VA_ARGS__);       \
+			zlog_err("%s: " fmt, __func__, ##__VA_ARGS__);         \
 	} while (0)
 #define MGMTD_DS_ERR(fmt, ...)                                                 \
 	zlog_err("%s: ERROR: " fmt, __func__, ##__VA_ARGS__)
@@ -107,6 +109,14 @@ static int mgmt_ds_replace_dst_with_src_ds(struct mgmt_ds_ctx *src,
 	else
 		dst->root.dnode_root = dst_dnode;
 
+	if (src->ds_id == MGMTD_DS_CANDIDATE) {
+		/*
+		 * Drop the changes in scratch-buffer.
+		 */
+		MGMTD_DS_DBG("Emptying Candidate Scratch buffer!");
+		nb_config_diff_del_changes(&src->root.cfg_root->cfg_chgs);
+	}
+
 	if (dst->ds_id == MGMTD_DS_RUNNING) {
 		if (ly_out_new_filepath(MGMTD_STARTUP_DS_FILE_PATH, &out)
 		    == LY_SUCCESS)
@@ -141,6 +151,14 @@ static int mgmt_ds_merge_src_with_dst_ds(struct mgmt_ds_ctx *src,
 		return ret;
 	}
 
+	if (src->ds_id == MGMTD_DS_CANDIDATE) {
+		/*
+		 * Drop the changes in scratch-buffer.
+		 */
+		MGMTD_DS_DBG("Emptying Candidate Scratch buffer!");
+		nb_config_diff_del_changes(&src->root.cfg_root->cfg_chgs);
+	}
+
 	if (dst->ds_id == MGMTD_DS_RUNNING) {
 		if (ly_out_new_filepath(MGMTD_STARTUP_DS_FILE_PATH, &out)
 		    == LY_SUCCESS)
@@ -169,6 +187,17 @@ static int mgmt_ds_load_cfg_from_file(const char *filepath,
 	return 0;
 }
 
+void mgmt_ds_reset_candidate(void)
+{
+	struct lyd_node *dnode = mm->candidate_ds->root.cfg_root->dnode;
+	if (dnode)
+		yang_dnode_free(dnode);
+
+	dnode = yang_dnode_new(ly_native_ctx, true);
+	mm->candidate_ds->root.cfg_root->dnode = dnode;
+}
+
+
 int mgmt_ds_init(struct mgmt_master *mm)
 {
 	struct lyd_node *root;
@@ -194,6 +223,12 @@ int mgmt_ds_init(struct mgmt_master *mm)
 	candidate.config_ds = true;
 	candidate.ds_id = MGMTD_DS_CANDIDATE;
 
+	/*
+	 * Redirect lib/vty candidate-config datastore to the global candidate
+	 * config Ds on the MGMTD process.
+	 */
+	vty_mgmt_candidate_config = candidate.root.cfg_root;
+
 	oper.root.dnode_root = yang_dnode_new(ly_native_ctx, true);
 	oper.config_ds = false;
 	oper.ds_id = MGMTD_DS_OPERATIONAL;
@@ -208,7 +243,6 @@ int mgmt_ds_init(struct mgmt_master *mm)
 
 void mgmt_ds_destroy(void)
 {
-
 	/*
 	 * TODO: Free the datastores.
 	 */
@@ -277,21 +311,15 @@ int mgmt_ds_unlock(struct mgmt_ds_ctx *ds_ctx)
 	return 0;
 }
 
-int mgmt_ds_merge_dss(struct mgmt_ds_ctx *src_ds_ctx,
-		      struct mgmt_ds_ctx *dst_ds_ctx, bool updt_cmt_rec)
-{
-	if (mgmt_ds_merge_src_with_dst_ds(src_ds_ctx, dst_ds_ctx) != 0)
-		return -1;
-
-	return 0;
-}
-
 int mgmt_ds_copy_dss(struct mgmt_ds_ctx *src_ds_ctx,
 		     struct mgmt_ds_ctx *dst_ds_ctx, bool updt_cmt_rec)
 {
 	if (mgmt_ds_replace_dst_with_src_ds(src_ds_ctx, dst_ds_ctx) != 0)
 		return -1;
 
+	if (updt_cmt_rec && dst_ds_ctx->ds_id == MGMTD_DS_RUNNING)
+		mgmt_history_new_record(dst_ds_ctx);
+
 	return 0;
 }
 
@@ -377,14 +405,16 @@ static int mgmt_walk_ds_nodes(
 		num_left--;
 	}
 
-	/* If the base_xpath points to leaf node, we can skip the tree walk */
-	if (base_dnode->schema->nodetype & LYD_NODE_TERM)
+	/*
+	 * If the base_xpath points to a leaf node, or we don't need to
+	 * visit any children we can skip the tree walk.
+	 */
+	if (!childs_as_well || base_dnode->schema->nodetype & LYD_NODE_TERM)
 		return 0;
 
 	indx = 0;
 	LY_LIST_FOR (lyd_child(base_dnode), dnode) {
 		assert(dnode->schema && dnode->schema->priv);
-		nbnode = (struct nb_node *)dnode->schema->priv;
 
 		xpath = NULL;
 		if (xpaths) {
@@ -407,9 +437,6 @@ static int mgmt_walk_ds_nodes(
 		assert(xpath);
 		MGMTD_DS_DBG(" -- XPATH: %s", xpath);
 
-		if (!childs_as_well)
-			continue;
-
 		if (num_nodes)
 			num_found = num_left;