Add support for unit file enable/disable and daemon-reload

Add Reload, EnableUnitFiles and DisableUnitFiles in Node and internal Agent
Implement and use passthough methods in manager node and agent
Implement hirtectl enable/disable/daemon-reload
hirtectl - call daemon-reload after unit enable/disable
Update the man page
Add doc and example

Signed-off-by: Ygal Blum <[email protected]>

data/org.containers.hirte.Node.xml

@@ -43,9 +43,22 @@
       <arg name="runtime" type="b" direction="in" />
       <arg name="keyvalues" type="a(sv)" direction="in" />
     </method>
+    <method name="EnableUnitFiles">
+      <arg name="files" type="as" direction="in" />
+      <arg name="runtime" type="b" direction="in" />
+      <arg name="force" type="b" direction="in" />
+      <arg name="carries_install_info" type="b" direction="out" />
+      <arg name="changes" type="a{sss}" direction="out" />
+    </method>
+    <method name="DisableUnitFiles">
+      <arg name="files" type="as" direction="in" />
+      <arg name="runtime" type="b" direction="in" />
+      <arg name="changes" type="a{sss}" direction="out" />
+    </method>
     <method name="ListUnits">
       <arg name="units" type="a(ssssssouso)" direction="out" />
     </method>
+    <method name="Reload" />
 
     <property name="Name" type="s" access="read" />
     <property name="Status" type="s" access="read" />

data/org.containers.hirte.internal.Agent.xml

@@ -43,6 +43,18 @@
       <arg name="runtime" type="b" direction="in" />
       <arg name="keyvalues" type="a(sv)" direction="in" />
     </method>
+    <method name="EnableUnitFiles">
+      <arg name="files" type="as" direction="in" />
+      <arg name="runtime" type="b" direction="in" />
+      <arg name="force" type="b" direction="in" />
+      <arg name="carries_install_info" type="b" direction="out" />
+      <arg name="changes" type="a{sss}" direction="out" />
+    </method>
+    <method name="DisableUnitFiles">
+      <arg name="files" type="as" direction="in" />
+      <arg name="runtime" type="b" direction="in" />
+      <arg name="changes" type="a{sss}" direction="out" />
+    </method>
     <method name="ListUnits">
       <arg name="units" type="a(ssssssouso)" direction="out" />
     </method>
@@ -60,6 +72,7 @@
     <method name="StopDep">
       <arg name="unit" type="s" direction="in" />
     </method>
+    <method name="Reload" />
 
     <signal name="JobDone">
       <arg name="id" type="u" />

doc/api-examples/enable-unit.py

@@ -0,0 +1,33 @@
+#!/usr/bin/python3
+
+import sys
+from collections import namedtuple
+import dasbus.connection
+bus = dasbus.connection.SystemMessageBus()
+
+EnabledServiceInfo = namedtuple("EnabledServicesInfo", ["op_type", "symlink_file", "symlink_dest"])
+EnableResponse = namedtuple("EnableResponse", ["carries_install_info", "enabled_services_info"])
+
+if len(sys.argv) < 2:
+    print(f"Usage: {sys.argv[0]} node_name unit_name...")
+    sys.exit(1)
+
+node_name = sys.argv[1]
+
+manager = bus.get_proxy("org.containers.hirte",  "/org/containers/hirte")
+node_path = manager.GetNode(node_name)
+node = bus.get_proxy("org.containers.hirte",  node_path)
+
+response = node.EnableUnitFiles(sys.argv[2:], False, False)
+enable_response = EnableResponse(*response)
+if enable_response.carries_install_info:
+    print("The unit files included enablement information")
+else:
+    print("The unit files did not include any enablement information")
+
+for e in enable_response.enabled_services_info:
+    enabled_service_info = EnabledServiceInfo(*e)
+    if enabled_service_info.op_type == "symlink":
+        print(f"Created symlink {enabled_service_info.symlink_file} -> {enabled_service_info.symlink_dest}")
+    elif enabled_service_info.op_type == "unlink":
+        print(f"Removed \"{enabled_service_info.symlink_file}\".")

doc/docs/api/description.md

@@ -146,6 +146,23 @@ Object path: `/org/containers/hirte/node/$name`
 
     Kill a unit on the node. Arguments and semantics are equivalent to the systemd `KillUnit()` method.
 
+  * `EnableUnitFiles(in  as files, in  b runtime, in  b force, out b carries_install_info, out a(sss) changes);`
+
+    `EnableUnitFiles()` may be used to enable one or more units in the system (by creating symlinks to them in /etc/ or /run/).
+    It takes a list of unit files to enable
+    (either just file names or full absolute paths if the unit files are residing outside the usual unit search paths)
+    and two booleans: the first controls whether the unit shall be enabled for runtime only (true, /run/), or persistently (false, /etc/).
+    The second one controls whether symlinks pointing to other units shall be replaced if necessary.
+    This method returns one boolean and an array of the changes made.
+    The boolean signals whether the unit files contained any enablement information (i.e. an [Install] section).
+    The changes array consists of structures with three strings: the type of the change (one of "symlink" or "unlink"),
+    the file name of the symlink and the destination of the symlink.
+
+  * `DisableUnitFiles(in  as files, in  b runtime, out a(sss) changes);`
+
+    `DisableUnitFiles()` is similar to `EnableUnitFiles()` but
+    disables the specified units by removing all symlinks to them in /etc/ and /run/
+
   * `GetUnitProperties(in s name, in s interface, out a{sv} props)`
 
     Returns the current properties for a named unit on the node. The returned properties are the same as you would
@@ -165,6 +182,10 @@ Object path: `/org/containers/hirte/node/$name`
     Returns all the currently loaded systemd units on this node. The returned structure is the same as the one returned
     by the systemd `ListUnits()` call.
 
+  * `Reload()`
+
+    `Reload()` may be invoked to reload all unit files.
+
 #### Properties
 
   * `Name` - `s`

doc/docs/api/examples.md

@@ -66,3 +66,11 @@ pip3 install dasbus
 ```
 
 ---
+
+### Enable unit files
+
+```python
+--8<-- "api-examples/enable-unit.py"
+```
+
+---

doc/man/hirtectl.1.md

@@ -26,14 +26,22 @@ Print usage statement and exit.
 
 Performs one of the listed lifecycle operations on the given systemd unit for the `hirte-agent`.
 
+### **hirtectl** [*enable|disable*] [*agent*] [*unit1*,*...*]
+
+Enable/Disable the list of systemd unit files for the `hirte-agent`.
+
 ### **hirtectl** *list-units* [*agent*]
 
 Fetches information about all systemd units on the hirte-agents. If [hirte-agent] is not specified, all agents are queried.
 
 ### **hirtectl** *monitor* [*agent*] [*unit1*,*unit2*,*...*]
 
-Creates a monitor on the given agent to observe changes in the specified units. Wildcards **\*** to match all agents and/or units are also supported. 
+Creates a monitor on the given agent to observe changes in the specified units. Wildcards **\*** to match all agents and/or units are also supported.
 
 **Example:**
 
-hirtectl monitor \\\* dbus.service,apache2.service
+hirtectl monitor \\\* dbus.service,apache2.service
+
+### **hirtectl** [*daemon-reload*] [*agent*]
+
+Performs `daemon-reload` for the `hirte-agent`.

src/agent/agent.c

@@ -652,6 +652,48 @@ static AgentUnitInfo *agent_ensure_unit_info(Agent *agent, const char *unit) {
         return info;
 }
 
+static int agent_method_passthrough_to_systemd_cb(
+                sd_bus_message *m, void *userdata, UNUSED sd_bus_error *ret_error) {
+        _cleanup_systemd_request_ SystemdRequest *req = userdata;
+
+        if (sd_bus_message_is_method_error(m, NULL)) {
+                return sd_bus_reply_method_error(req->request_message, sd_bus_message_get_error(m));
+        }
+
+        _cleanup_sd_bus_message_ sd_bus_message *reply = NULL;
+        int r = sd_bus_message_new_method_return(req->request_message, &reply);
+        if (r < 0) {
+                return r;
+        }
+
+        r = sd_bus_message_copy(reply, m, true);
+        if (r < 0) {
+                return r;
+        }
+
+        return sd_bus_message_send(reply);
+}
+
+static int agent_method_passthrough_to_systemd(sd_bus_message *m, void *userdata, UNUSED sd_bus_error *ret_error) {
+        Agent *agent = userdata;
+        _cleanup_systemd_request_ SystemdRequest *req = agent_create_request(
+                        agent, m, sd_bus_message_get_member(m));
+        if (req == NULL) {
+                return sd_bus_reply_method_errorf(m, SD_BUS_ERROR_FAILED, "Internal error");
+        }
+
+        int r = sd_bus_message_copy(req->message, m, true);
+        if (r < 0) {
+                return sd_bus_reply_method_errorf(m, SD_BUS_ERROR_FAILED, "Internal error");
+        }
+
+        if (!systemd_request_start(req, agent_method_passthrough_to_systemd_cb)) {
+                return sd_bus_reply_method_errorf(m, SD_BUS_ERROR_FAILED, "Internal error");
+        }
+
+        return 1;
+}
+
 /*************************************************************************
  ********** org.containers.hirte.internal.Agent.ListUnits ****************
  ************************************************************************/
@@ -1324,6 +1366,9 @@ static const sd_bus_vtable internal_agent_vtable[] = {
         SD_BUS_SIGNAL_WITH_NAMES("Heartbeat", "s", SD_BUS_PARAM(agent_name), 0),
         SD_BUS_METHOD("StartDep", "s", "", agent_method_start_dep, 0),
         SD_BUS_METHOD("StopDep", "s", "", agent_method_stop_dep, 0),
+        SD_BUS_METHOD("EnableUnitFiles", "asbb", "ba(sss)", agent_method_passthrough_to_systemd, 0),
+        SD_BUS_METHOD("DisableUnitFiles", "asb", "a(sss)", agent_method_passthrough_to_systemd, 0),
+        SD_BUS_METHOD("Reload", "", "", agent_method_passthrough_to_systemd, 0),
         SD_BUS_VTABLE_END
 };