YAML consolidation prelude: new YAML dump APIs (FR-702)

include/netplan.h

@@ -54,11 +54,13 @@ netplan_state_get_netdefs_size(const NetplanState* np_state);
 NETPLAN_PUBLIC NetplanNetDefinition*
 netplan_state_get_netdef(const NetplanState* np_state, const char* id);
 
+/* Dump the whole yaml configuration into the given file, regardless of the origin
+ * of each definition.
+ */
 NETPLAN_PUBLIC gboolean
-netplan_state_write_yaml(
+netplan_state_dump_yaml(
         const NetplanState* np_state,
-        const char* file_hint,
-        const char* rootdir,
+        int output_fd,
         GError** error);
 
 NETPLAN_PUBLIC gboolean

netplan/libnetplan.py

@@ -127,6 +127,9 @@ def _load_abi(cls):
         lib.netplan_state_get_netdef.argtypes = [_NetplanStateP, c_char_p]
         lib.netplan_state_get_netdef.restype = _NetplanNetDefinitionP
 
+        lib.netplan_state_dump_yaml.argtypes = [_NetplanStateP, c_int, _GErrorPP]
+        lib.netplan_state_dump_yaml.restype = c_int
+
         cls._abi_loaded = True
 
     def __init__(self):
@@ -139,6 +142,10 @@ def __del__(self):
     def import_parser_results(self, parser):
         _checked_lib_call(lib.netplan_state_import_parser_results, self._ptr, parser._ptr)
 
+    def dump_yaml(self, output_file):
+        fd = output_file.fileno()
+        _checked_lib_call(lib.netplan_state_dump_yaml, self._ptr, fd)
+
     def __len__(self):
         return lib.netplan_state_get_netdefs_size(self._ptr)
 
@@ -242,3 +249,14 @@ def netplan_get_ids_for_devtype(devtype, rootdir):
         raise Exception(err.contents.message.decode('utf-8'))
     nds = list(_NetdefIterator(__GlobalState(), devtype))
     return [nd.id for nd in nds]
+
+
+lib.netplan_util_dump_yaml_subtree.argtypes = [c_char_p, c_int, c_int, _GErrorPP]
+lib.netplan_util_dump_yaml_subtree.restype = c_int
+
+
+def dump_yaml_subtree(prefix, input_file, output_file):
+    _checked_lib_call(lib.netplan_util_dump_yaml_subtree,
+                      prefix.encode('utf-8'),
+                      input_file.fileno(),
+                      output_file.fileno())

src/abi_compat.c

@@ -36,6 +36,7 @@
 #include <glib.h>
 #include <glib/gstdio.h>
 #include <errno.h>
+#include <fcntl.h>
 
 /* These arrays are not useful per-say, but allow us to export the various
  * struct offsets of the netplan_state members to the linker, which can use
@@ -228,8 +229,15 @@ netplan_state_write_yaml(const NetplanState* np_state, const char* file_hint, co
 NETPLAN_ABI void
 write_netplan_conf_full(const char* file_hint, const char* rootdir)
 {
+    g_autofree gchar *path = NULL;
     netplan_finish_parse(NULL);
-    netplan_state_write_yaml(&global_state, file_hint, rootdir, NULL);
+    if (!netplan_state_has_nondefault_globals(&global_state) &&
+        !netplan_state_get_netdefs_size(&global_state))
+        return;
+    path = g_build_path(G_DIR_SEPARATOR_S, rootdir ?: G_DIR_SEPARATOR_S, "etc", "netplan", file_hint, NULL);
+    int fd = open(path, O_WRONLY | O_CREAT | O_TRUNC, 0640);
+    netplan_state_dump_yaml(&global_state, fd, NULL);
+    close(fd);
 }
 
 NETPLAN_PUBLIC gboolean

src/netplan.c

@@ -16,11 +16,17 @@
  */
 
 #include <glib.h>
+#include <glib/gstdio.h>
 #include <yaml.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
 
 #include "netplan.h"
 #include "parse.h"
+#include "types.h"
 #include "yaml-helpers.h"
+#include "util-internal.h"
 #include "names.h"
 
 gchar *tmp = NULL;
@@ -491,21 +497,6 @@ write_routes(yaml_event_t* event, yaml_emitter_t* emitter, const NetplanNetDefin
 err_path: return FALSE; // LCOV_EXCL_LINE
 }
 
-static gboolean
-has_openvswitch(const NetplanOVSSettings* ovs, NetplanBackend backend, GHashTable *ovs_ports) {
-    return (ovs_ports && g_hash_table_size(ovs_ports) > 0)
-            || (ovs->external_ids && g_hash_table_size(ovs->external_ids) > 0)
-            || (ovs->other_config && g_hash_table_size(ovs->other_config) > 0)
-            || ovs->lacp
-            || ovs->fail_mode
-            || ovs->mcast_snooping
-            || ovs->rstp
-            || ovs->protocols
-            || (ovs->ssl.ca_certificate || ovs->ssl.client_certificate || ovs->ssl.client_key)
-            || (ovs->controller.connection_mode || ovs->controller.addresses)
-            || backend == NETPLAN_BACKEND_OVS;
-}
-
 static gboolean
 write_openvswitch(yaml_event_t* event, yaml_emitter_t* emitter, const NetplanOVSSettings* ovs, NetplanBackend backend, GHashTable *ovs_ports)
 {
@@ -890,38 +881,25 @@ contains_netdef_type(gconstpointer value, gconstpointer user_data)
     return nd->type == *type ? 0 : -1;
 }
 
-/**
- * Generate the Netplan YAML configuration for all netdefs in the state
- * @np_state: the state for which to generate the config
- * @file_hint: Name hint for the generated output YAML file
- * @rootdir: If not %NULL, generate configuration in this root directory
- *           (useful for testing).
- */
-NETPLAN_INTERNAL gboolean
-netplan_state_write_yaml(const NetplanState* np_state, const char* file_hint, const char* rootdir, GError** error)
+static gboolean
+netplan_netdef_list_write_yaml(const NetplanState* np_state, GList* netdefs, int out_fd, GError** error)
 {
-    g_autofree gchar *path = NULL;
     GHashTable *ovs_ports = NULL;
-    GList* netdefs = np_state->netdefs_ordered;
 
-    gboolean global_values = (np_state->backend != NETPLAN_BACKEND_NONE
-                              || has_openvswitch(&np_state->ovs_settings, NETPLAN_BACKEND_NONE, NULL));
-
-    if (!global_values && netplan_state_get_netdefs_size(np_state) == 0) {
-        g_debug("No data/netdefs to serialize into YAML.");
-        return TRUE;
-    }
-
-    path = g_build_path(G_DIR_SEPARATOR_S, rootdir ?: G_DIR_SEPARATOR_S, "etc", "netplan", file_hint, NULL);
+    int dup_fd = dup(out_fd);
+    if (dup_fd < 0)
+        goto file_error; // LCOV_EXCL_LINE
+    FILE* out_stream = fdopen(dup_fd, "w");
+    if (!out_stream)
+        goto file_error;
 
     /* Start rendering YAML output */
     yaml_emitter_t emitter_data;
     yaml_event_t event_data;
     yaml_emitter_t* emitter = &emitter_data;
     yaml_event_t* event = &event_data;
-    FILE *output = fopen(path, "wb");
 
-    YAML_OUT_START(event, emitter, output);
+    YAML_OUT_START(event, emitter, out_stream);
     /* build the netplan boilerplate YAML structure */
     YAML_SCALAR_PLAIN(event, emitter, "network");
     YAML_MAPPING_OPEN(event, emitter);
@@ -973,16 +951,35 @@ netplan_state_write_yaml(const NetplanState* np_state, const char* file_hint, co
 
     /* Tear down the YAML emitter */
     YAML_OUT_STOP(event, emitter);
-    fclose(output);
+    fclose(out_stream);
     return TRUE;
 
     // LCOV_EXCL_START
 err_path:
     g_set_error(error, G_MARKUP_ERROR, G_MARKUP_ERROR_INVALID_CONTENT, "Error generating YAML: %s", emitter->problem);
     yaml_emitter_delete(emitter);
-    fclose(output);
+    fclose(out_stream);
     return FALSE;
     // LCOV_EXCL_STOP
+
+file_error:
+    g_set_error(error, G_FILE_ERROR, errno, "%s", strerror(errno));
+    return FALSE;
+}
+
+/**
+ * Dump the whole state into a single YAML file.
+ *
+ * @np_state: the state for which to generate the config
+ * @out_fd: File descriptor to an opened file into which to dump the content
+ */
+gboolean
+netplan_state_dump_yaml(const NetplanState* np_state, int out_fd, GError** error)
+{
+    if (!np_state->netdefs_ordered && !netplan_state_has_nondefault_globals(np_state))
+        return TRUE;
+
+    return netplan_netdef_list_write_yaml(np_state, np_state->netdefs_ordered, out_fd, error);
 }
 
 /* XXX: implement the following functions, once needed:

src/types.c

@@ -22,6 +22,7 @@
 
 #include <glib.h>
 #include "types.h"
+#include "util-internal.h"
 
 #define FREE_AND_NULLIFY(ptr) { g_free(ptr); ptr = NULL; }
 
@@ -436,3 +437,10 @@ netplan_netdef_get_id(const NetplanNetDefinition* netdef)
 
 NETPLAN_INTERNAL const char*
 _netplan_netdef_id(NetplanNetDefinition* netdef) __attribute__((alias("netplan_netdef_get_id")));
+
+gboolean
+netplan_state_has_nondefault_globals(const NetplanState* np_state)
+{
+        return (np_state->backend != NETPLAN_BACKEND_NONE)
+                || has_openvswitch(&np_state->ovs_settings, NETPLAN_BACKEND_NONE, NULL);
+}

src/types.h

@@ -511,3 +511,6 @@ ip_rule_clear(NetplanIPRule** rule);
 
 void
 route_clear(NetplanIPRoute** route);
+
+gboolean
+netplan_state_has_nondefault_globals(const NetplanState* np_state);

src/util-internal.h

@@ -79,3 +79,6 @@ process_input_file(const char* f);
 
 NETPLAN_INTERNAL gboolean
 process_yaml_hierarchy(const char* rootdir);
+
+gboolean
+has_openvswitch(const NetplanOVSSettings* ovs, NetplanBackend backend, GHashTable *ovs_ports);