[Devel] [Patch] snapshot-list JSON output

Denis Fondras openvz at ggl.ledeuns.net
Sun Feb 24 02:37:22 PST 2013


Hello,

I made a quick (and dirty) patch to make "vzctl snapshot-list <CTID>" 
able to output a JSON structure as it is easier to parse from my Pyhton 
management script.

The new option is "-J" and support the "-o" filtering.

I would be very happy if someone could help make it a little less dirty 
as I'm more of a sysadmin than a programmer.
Do not hesitate to comment it.

Denis

Here is a sample output :
----8<----------------------------------------
# ./vzctl snapshot-list 7775 -J -o parent_uuid,current,uuid,date,name,desc
{
   "snapshot": {
     "parent_uuid": "",
     "current": "",
     "uuid": "{d863723c-a106-4c5e-9037-946249e4826c}",
     "date": "2013-02-23 16:59:19",
     "name": "",
     "desc": ""
   },
   "snapshot": {
     "parent_uuid": "{d863723c-a106-4c5e-9037-946249e4826c}",
     "current": "*",
     "uuid": "{1e60191e-2a12-4a7f-8d45-216e36148014}",
     "date": "2013-02-24 12:27:40",
     "name": "Test",
     "desc": "Limited to 128 char :-( Hey! I'm not a programmer in the 
first place :p"
   }
}
----8<----------------------------------------



Here is the patch :
----8<----------------------------------------
diff -ru vzctl-4.2/src/snapshot-list.c vzctl-4.2-json/src/snapshot-list.c
--- vzctl-4.2/src/snapshot-list.c	2013-02-16 02:06:40.000000000 +0100
+++ vzctl-4.2-json/src/snapshot-list.c	2013-02-24 12:10:32.019138573 +0100
@@ -33,81 +33,111 @@
  	return g_last_field ? "%s\n" : fmt;
  }

-static void print_uuid(struct vzctl_snapshot_data *p)
+static void print_uuid(struct vzctl_snapshot_data *p, char *ret)
  {
-	printf(FMT("%-38s "), p->guid);
+	if (ret == NULL)
+		printf(FMT("%-38s "), p->guid);
+	else {
+		snprintf(ret,128,"%s",p->guid);
+	}
  }

-static void print_date(struct vzctl_snapshot_data *p)
+static void print_date(struct vzctl_snapshot_data *p, char *ret)
  {
-	printf(FMT("%-19s "), p->date ? p->date : "");
+	if (ret == NULL)
+		printf(FMT("%-19s "), p->date ? p->date : "");
+	else {
+		snprintf(ret,128,"%s",p->date ? p->date : "");
+	}
  }

-static void print_name(struct vzctl_snapshot_data *p)
+static void print_name(struct vzctl_snapshot_data *p, char *ret)
  {
-	printf(FMT("%-32s "), p->name ? p->name : "");
+	if (ret == NULL)
+		printf(FMT("%-32s "), p->name ? p->name : "");
+	else {
+		snprintf(ret,128,"%s",p->name ? p->name : "");
+        }
  }

-static void print_desc(struct vzctl_snapshot_data *p)
+static void print_desc(struct vzctl_snapshot_data *p, char *ret)
  {
-	printf(FMT("%-38s "), p->desc ? p->desc : "");
+	if (ret == NULL)
+		printf(FMT("%-38s "), p->desc ? p->desc : "");
+	else {
+		snprintf(ret,128,"%s",p->desc ? p->desc : "");
+	}
  }

-static void print_parent_uuid(struct vzctl_snapshot_data *p)
+static void print_parent_uuid(struct vzctl_snapshot_data *p, char *ret)
  {
-	printf(FMT("%-38s "), p->parent_guid);
+	if (ret == NULL)
+		printf(FMT("%-38s "), p->parent_guid);
+	else {
+		snprintf(ret,128,"%s",p->parent_guid);
+	}
  }

-static void print_current(struct vzctl_snapshot_data *p)
+static void print_current(struct vzctl_snapshot_data *p, char *ret)
  {
-	printf(FMT("%1s "), p->current ? "*" : "");
+	if (ret == NULL)
+		printf(FMT("%1s "), p->current ? "*" : "");
+	else {
+		snprintf(ret,128,"%s",p->current ? "*" : "");
+	}
  }

-static void print_device(struct vzctl_snapshot_data *p)
+static void print_device(struct vzctl_snapshot_data *p, char *ret)
  {
-	char buf[PATH_MAX];
-	char dev[PATH_MAX] = "";
+	if (ret == NULL) {
+		char buf[PATH_MAX];
+		char dev[PATH_MAX] = "";

-	ploop.set_component_name(g_di,
+		ploop.set_component_name(g_di,
  			generate_snapshot_component_name(g_envid, p->guid, buf, sizeof(buf)));

-	if (ploop.get_dev(g_di, dev, sizeof(dev)))
-		goto err;
+		if (ploop.get_dev(g_di, dev, sizeof(dev)))
+			goto err;

-	printf(FMT("%-32s "), dev);
-	return;
-err:
-	printf(FMT("%-32s "), "");
-	fprintf(stderr, "%s", ploop.get_last_error());
-	error++;
+		printf(FMT("%-32s "), dev);
+		return;
+	err:
+		printf(FMT("%-32s "), "");
+		fprintf(stderr, "%s", ploop.get_last_error());
+		error++;
+	} else {
+	}
  }

-static void print_target(struct vzctl_snapshot_data *p)
+static void print_target(struct vzctl_snapshot_data *p, char *ret)
  {
-	char buf[PATH_MAX];
-	char dev[PATH_MAX];
+	if (ret == NULL) {
+		char buf[PATH_MAX];
+		char dev[PATH_MAX];

-	ploop.set_component_name(g_di,
+		ploop.set_component_name(g_di,
  			generate_snapshot_component_name(g_envid, p->guid, buf, sizeof(buf)));

-	if (ploop.get_dev(g_di, dev, sizeof(dev)))
-		goto err;
-	if (ploop.get_mnt_by_dev(dev, buf, sizeof(buf)))
-		goto err;
-
-	printf(FMT("%-32s "), buf);
-	return;
-err:
-	printf(FMT("%-32s "), "");
-	fprintf(stderr, "%s", ploop.get_last_error());
-	error++;
+		if (ploop.get_dev(g_di, dev, sizeof(dev)))
+			goto err;
+		if (ploop.get_mnt_by_dev(dev, buf, sizeof(buf)))
+			goto err;
+
+		printf(FMT("%-32s "), buf);
+		return;
+	err:
+		printf(FMT("%-32s "), "");
+		fprintf(stderr, "%s", ploop.get_last_error());
+		error++;
+	} else {
+	}
  }

  struct snapshot_field {
  	char *name;
  	char *hdr;
  	char *fmt;
-	void (* print_fn)(struct vzctl_snapshot_data *p);
+	void (* print_fn)(struct vzctl_snapshot_data *p, char *);
  } field_tbl[] =
  {
  {"uuid", "UUID", "%-38s", print_uuid},
@@ -240,7 +270,7 @@
  static void usage_snapshot_list(int err)
  {
  	fprintf(err ? stderr : stdout,
-		"vzctl snapshot-list <ctid|name> [-H] [-o field[,field...]] [--id 
<uuid>]\n"
+		"vzctl snapshot-list <ctid|name> [-H] [-J] [-o field[,field...]] 
[--id <uuid>]\n"
  		"vzctl snapshot-list <ctid|name> -L | --list\n"
  	       );
  }
@@ -249,7 +279,7 @@
  		const char *ve_private)
  {
  	int c, ret;
-	int no_hdr = 0;
+	int no_hdr = 0, json = 0;
  	struct vzctl_snapshot_tree *tree = NULL;
  	struct id_entry *field_entry = NULL;
  	struct id_entry * uuid_entry = NULL;
@@ -264,13 +294,14 @@
  		{"uuid",	required_argument, NULL, 'u'},
  			{"id",	required_argument, NULL, 'u'},
  		{"list",	no_argument, NULL, 'L'},
+		{"json",	no_argument, NULL, 'J'},
  		{ NULL, 0, NULL, 0 }
  	};

  	g_envid = envid;
  	while (1) {
  		int option_index = -1;
-		c = getopt_long(argc, argv, "HhLo:u:",
+		c = getopt_long(argc, argv, "HJhLo:u:",
  				list_options, &option_index);
  		if (c == -1)
  			break;
@@ -296,6 +327,9 @@
  		case 'L':
  			print_names();
  			return 0;
+		case 'J':
+			no_hdr = json = 1;
+			break;
  		default:
  			usage_snapshot_list(1);
  			return VZ_INVALID_PARAMETER_SYNTAX;
@@ -352,12 +386,34 @@

  	print_hdr(no_hdr);

-	list_for_each(uuid_entry, &g_uuid_list_head, list) {
-		list_for_each(field_entry, &g_field_order_head, list) {
-			g_last_field = ((void *)g_field_order_head.prev == (void*)field_entry);
-			field_tbl[field_entry->id].print_fn(tree->snapshots[uuid_entry->id]);
+	if (json) {
+		int first_json_entry = -1;
+		printf("{");
+                list_for_each(uuid_entry, &g_uuid_list_head, list) {
+			first_json_entry++;
+			if (first_json_entry) printf(",");
+			printf("\n  \"snapshot\": {\n");
+                        list_for_each(field_entry, &g_field_order_head, 
list) {
+				g_last_field = ((void *)g_field_order_head.prev == (void*)field_entry);
+				char ptr[129];
+				memset(ptr,0,129);
+			 
field_tbl[field_entry->id].print_fn(tree->snapshots[uuid_entry->id], ptr);
+                                printf("    \"%s\": 
\"%s\"%s\n",field_tbl[field_entry->id].name,ptr,g_last_field?"":",");
+				
+			}
+			printf("  }");
  		}
+		printf("\n}\n");
  	}
+	else {
+		list_for_each(uuid_entry, &g_uuid_list_head, list) {
+			list_for_each(field_entry, &g_field_order_head, list) {
+				g_last_field = ((void *)g_field_order_head.prev == (void*)field_entry);
+			 
field_tbl[field_entry->id].print_fn(tree->snapshots[uuid_entry->id], NULL);
+			}
+		}
+	}
+
  	ploop.free_diskdescriptor(g_di);

  	return 0;
diff -ru vzctl-4.2/src/vzctl.c vzctl-4.2-json/src/vzctl.c
--- vzctl-4.2/src/vzctl.c	2013-02-16 02:06:40.000000000 +0100
+++ vzctl-4.2-json/src/vzctl.c	2013-02-23 17:28:20.671138739 +0100
@@ -73,7 +73,7 @@
  "vzctl snapshot <ctid> [--id <uuid>] [--name <name>] [--description 
<desc>]\n"
  "   [--skip-suspend]\n"
  "vzctl snapshot-switch | snapshot-delete <ctid> --id <uuid>\n"
-"vzctl snapshot-list <ctid> [-H] [-o field[,field...]] [--id <uuid>]\n"
+"vzctl snapshot-list <ctid> [-H] [-J] [-o field[,field...]] [--id 
<uuid>]\n"
  #endif
  "vzctl quotaon | quotaoff | quotainit <ctid>\n"
  "vzctl console <ctid> [ttyno]\n"
----8<----------------------------------------



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