Adapt iSCSI handling to the new architecture (#1187)

This PR implements an HTTP/JSON API for managing iSCSI devices. It works
as a proxy over the real API which is implemented in D-Bus.

The API is composed of these parts:

* A bunch of HTTP/JSON endpoints to manage the iSCSI configuration.
* A stream of iSCSI nodes changes (adding, changing or removing nodes).
* A stream of initiator changes (not implemented yet).

NOTE: this PR should be merged after #1175.

## To do

- [x] Adapt the client
- [x] Populate the cache of ISCSI nodes in the stream
- [x] Allow changing the initiator name
- [x] Allow changing the startup
- [x] Emit initiator changes
- [x] OpenAPI documentation
- [x] Remove calls to `unwrap()` in the initiator changes stream

## References

* Trello: https://trello.com/c/TEQvbxAU/

doc/dbus/bus/org.opensuse.Agama.Storage1.ISCSI.Initiator.bus.xml

@@ -0,0 +1 @@
+org.opensuse.Agama.Storage1.bus.xml

doc/dbus/bus/org.opensuse.Agama.Storage1.ISCSI.Node.bus.xml

@@ -0,0 +1,46 @@
+<!DOCTYPE node PUBLIC "-//freedesktop//DTD D-BUS Object Introspection 1.0//EN"
+"http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">
+<node name="/org/opensuse/Agama/Storage1/iscsi_nodes/1">
+  <interface name="org.freedesktop.DBus.Properties">
+    <method name="Get">
+      <arg name="interface_name" direction="in" type="s"/>
+      <arg name="property_name" direction="in" type="s"/>
+      <arg name="value" direction="out" type="v"/>
+    </method>
+    <method name="Set">
+      <arg name="interface_name" direction="in" type="s"/>
+      <arg name="property_name" direction="in" type="s"/>
+      <arg name="val" direction="in" type="v"/>
+    </method>
+    <method name="GetAll">
+      <arg name="interface_name" direction="in" type="s"/>
+      <arg name="value" direction="out" type="a{sv}"/>
+    </method>
+    <signal name="PropertiesChanged">
+      <arg name="interface" type="s"/>
+      <arg name="changed_properties" type="a{sv}"/>
+      <arg name="invalidated_properties" type="as"/>
+    </signal>
+  </interface>
+  <interface name="org.freedesktop.DBus.Introspectable">
+    <method name="Introspect">
+      <arg name="xml_data" direction="out" type="s"/>
+    </method>
+  </interface>
+  <interface name="org.opensuse.Agama.Storage1.ISCSI.Node">
+    <method name="Login">
+      <arg name="options" direction="in" type="a{sv}"/>
+      <arg name="result" direction="out" type="u"/>
+    </method>
+    <method name="Logout">
+      <arg name="result" direction="out" type="u"/>
+    </method>
+    <property type="s" name="Target" access="read"/>
+    <property type="s" name="Address" access="read"/>
+    <property type="u" name="Port" access="read"/>
+    <property type="s" name="Interface" access="read"/>
+    <property type="b" name="IBFT" access="read"/>
+    <property type="b" name="Connected" access="read"/>
+    <property type="s" name="Startup" access="readwrite"/>
+  </interface>
+</node>

doc/dbus/bus/org.opensuse.Agama.Storage1.bus.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <node name="/org/opensuse/Agama/Storage1">
+  <node name="iscsi_nodes" />
   <node name="zfcp_controllers" />
   <node name="zfcp_disks" />
   <interface name="org.freedesktop.DBus.Introspectable">

doc/dbus/org.opensuse.Agama.Storage1.ISCSI.Initiator.doc.xml

@@ -0,0 +1,21 @@
+<!DOCTYPE node PUBLIC "-//freedesktop//DTD D-BUS Object Introspection 1.0//EN"
+"http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">
+<node name="/org/opensuse/Agama/Storage1">
+  <node name="iscsi_nodes" />
+  <node name="zfcp_controllers" />
+  <node name="zfcp_disks" />
+  <interface name="org.opensuse.Agama.Storage1.ISCSI.Initiator">
+    <method name="Discover">
+      <arg name="address" direction="in" type="s"/>
+      <arg name="port" direction="in" type="u"/>
+      <arg name="options" direction="in" type="a{sv}"/>
+      <arg name="result" direction="out" type="u"/>
+    </method>
+    <method name="Delete">
+      <arg name="node" direction="in" type="o"/>
+      <arg name="result" direction="out" type="u"/>
+    </method>
+    <property type="s" name="InitiatorName" access="readwrite"/>
+    <property type="b" name="IBFT" access="read"/>
+  </interface>
+</node>

doc/dbus/org.opensuse.Agama.Storage1.ISCSI.Node.doc.xml

@@ -0,0 +1,20 @@
+<!DOCTYPE node PUBLIC "-//freedesktop//DTD D-BUS Object Introspection 1.0//EN"
+"http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">
+<node name="/org/opensuse/Agama/Storage1/iscsi_nodes/1">
+  <interface name="org.opensuse.Agama.Storage1.ISCSI.Node">
+    <method name="Login">
+      <arg name="options" direction="in" type="a{sv}"/>
+      <arg name="result" direction="out" type="u"/>
+    </method>
+    <method name="Logout">
+      <arg name="result" direction="out" type="u"/>
+    </method>
+    <property type="s" name="Target" access="read"/>
+    <property type="s" name="Address" access="read"/>
+    <property type="u" name="Port" access="read"/>
+    <property type="s" name="Interface" access="read"/>
+    <property type="b" name="IBFT" access="read"/>
+    <property type="b" name="Connected" access="read"/>
+    <property type="s" name="Startup" access="readwrite"/>
+  </interface>
+</node>

doc/dbus/org.opensuse.Agama.Storage1.Proposal.Calculator.doc.xml

@@ -1,6 +1,7 @@
 <!DOCTYPE node PUBLIC "-//freedesktop//DTD D-BUS Object Introspection 1.0//EN"
 "http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">
 <node name="/org/opensuse/Agama/Storage1">
+  <node name="iscsi_nodes" />
   <node name="zfcp_controllers" />
   <node name="zfcp_disks" />
   <!--

doc/dbus/org.opensuse.Agama.Storage1.doc.xml

@@ -1,6 +1,7 @@
 <!DOCTYPE node PUBLIC "-//freedesktop//DTD D-BUS Object Introspection 1.0//EN"
 "http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">
 <node name="/org/opensuse/Agama/Storage1">
+  <node name="iscsi_nodes" />
   <node name="zfcp_controllers" />
   <node name="zfcp_disks" />
   <interface name="org.opensuse.Agama.Storage1">

rust/agama-lib/src/dbus.rs

@@ -1,5 +1,5 @@
 use std::collections::HashMap;
-use zbus::zvariant::{self, OwnedValue, Value};
+use zbus::zvariant::{self, OwnedObjectPath, OwnedValue, Value};
 
 /// Nested hash to send to D-Bus.
 pub type NestedHash<'a> = HashMap<&'a str, HashMap<&'a str, zvariant::Value<'a>>>;
@@ -43,3 +43,81 @@ where
         Ok(None)
     }
 }
+
+#[macro_export]
+macro_rules! property_from_dbus {
+    ($self:ident, $field:ident, $key:expr, $dbus:ident, $type:ty) => {
+        if let Some(v) = get_optional_property($dbus, $key)? {
+            $self.$field = v;
+        }
+    };
+}
+
+/// Converts a hash map containing zbus non-owned values to hash map with owned ones.
+///
+/// NOTE: we could follow a different approach like building our own type (e.g.
+/// using the newtype idiom) and offering a better API.
+///
+/// * `source`: hash map containing non-onwed values ([zbus::zvariant::Value]).
+pub fn to_owned_hash(source: &HashMap<&str, Value<'_>>) -> HashMap<String, OwnedValue> {
+    let mut owned = HashMap::new();
+    for (key, value) in source.iter() {
+        if let Ok(owned_value) = value.try_into() {
+            owned.insert(key.to_string(), owned_value);
+        }
+    }
+    owned
+}
+
+/// Extracts the object ID from the path.
+///
+/// TODO: should we merge this feature with the "DeviceSid"?
+pub fn extract_id_from_path(path: &OwnedObjectPath) -> Result<u32, zvariant::Error> {
+    path.as_str()
+        .rsplit_once("/")
+        .and_then(|(_, id)| id.parse::<u32>().ok())
+        .ok_or_else(|| {
+            zvariant::Error::Message(format!("Could not extract the ID from {}", path.as_str()))
+        })
+}
+
+#[cfg(test)]
+mod tests {
+    use std::collections::HashMap;
+
+    use zbus::zvariant::{self, OwnedValue, Str};
+
+    use crate::dbus::{get_optional_property, get_property};
+
+    #[test]
+    fn test_get_property() {
+        let data: HashMap<String, OwnedValue> = HashMap::from([
+            ("Id".to_string(), (1 as u8).into()),
+            ("Device".to_string(), Str::from_static("/dev/sda").into()),
+        ]);
+        let id: u8 = get_property(&data, "Id").unwrap();
+        assert_eq!(id, 1);
+
+        let device: String = get_property(&data, "Device").unwrap();
+        assert_eq!(device, "/dev/sda".to_string());
+    }
+
+    #[test]
+    fn test_get_property_wrong_type() {
+        let data: HashMap<String, OwnedValue> =
+            HashMap::from([("Id".to_string(), (1 as u8).into())]);
+        let result: Result<u16, _> = get_property(&data, "Id");
+        assert_eq!(result, Err(zvariant::Error::IncorrectType));
+    }
+
+    #[test]
+    fn test_get_optional_property() {
+        let data: HashMap<String, OwnedValue> =
+            HashMap::from([("Id".to_string(), (1 as u8).into())]);
+        let id: Option<u8> = get_optional_property(&data, "Id").unwrap();
+        assert_eq!(id, Some(1));
+
+        let device: Option<String> = get_optional_property(&data, "Device").unwrap();
+        assert_eq!(device, None);
+    }
+}

rust/agama-lib/src/storage.rs

@@ -6,6 +6,9 @@ pub mod proxies;
 mod settings;
 mod store;
 
-pub use client::StorageClient;
+pub use client::{
+    iscsi::{ISCSIAuth, ISCSIClient, ISCSIInitiator, ISCSINode},
+    StorageClient,
+};
 pub use settings::StorageSettings;
 pub use store::StorageStore;

rust/agama-lib/src/storage/client.rs

@@ -15,6 +15,7 @@ use zbus::fdo::ObjectManagerProxy;
 use zbus::names::{InterfaceName, OwnedInterfaceName};
 use zbus::zvariant::{OwnedObjectPath, OwnedValue};
 use zbus::Connection;
+pub mod iscsi;
 
 type DBusObject = (
     OwnedObjectPath,