Rework the devshell

From: Chris Larson <[email protected]>

- Adds a utility metaclass for maintaining class registries
- Shifts the handling of spawning a terminal into a new 'terminal' python module
- Automatically selects an appropriate terminal based on what you have available on your machine
- Still allows manual selection, but in a more convenient way, and falls back to auto if you select an invalid or unavailable (not installed) terminal
- Improves how we spawn screen:

- Shows a warning when spawning it, so do_devshell doesn't appear to hang
- Spawns a named screen session 'devshell', to avoid confusion when the user already has other screen sessions running

Example usage of the new API for others (e.g. patch resolver) to use:

import oe.terminal
oe.terminal.run(command, terminal_title, d)

Pull URL: git://git.openembedded.org/openembedded-core-contrib
Branch: kergoth/devshell
Browse: http://git.openembedded.org/cgit.cgi/openembedded-core-contrib/log/?h=kergoth/devshell

Thanks,
Chris Larson <[email protected]>
---

Chris Larson (3):
oe.classutils: add module
Rework how the devshell functions
oe.terminal: improve how we spawn screen

 meta/classes/devshell.bbclass |   25 ++------
 meta/conf/bitbake.conf        |    9 +++
 meta/lib/oe/classutils.py     |   45 ++++++++++++++
 meta/lib/oe/terminal.py       |  131 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 191 insertions(+), 19 deletions(-)
 create mode 100644 meta/lib/oe/classutils.py
 create mode 100644 meta/lib/oe/terminal.py

From: Chris Larson <[email protected]>

This adds a ClassRegistry utility metaclass, as maintaining a class registry is a fairly common thing to do.

---
 meta/lib/oe/classutils.py |   43 +++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 43 insertions(+), 0 deletions(-)
 create mode 100644 meta/lib/oe/classutils.py

new file mode 100644
index 0000000..58188fd
@@ -0,0 +1,43 @@
+class ClassRegistry(type):
+    """Maintain a registry of classes, indexed by name.
+
+Note that this implementation requires that the names be unique, as it uses
+a dictionary to hold the classes by name.
+
+The name in the registry can be overridden via the 'name' attribute of the
+class, and the 'priority' attribute controls priority. The prioritized()
+method returns the registered classes in priority order.
+
+Subclasses of ClassRegistry may define an 'implemented' property to exert
+control over whether the class will be added to the registry (e.g. to keep
+abstract base classes out of the registry)."""
+    priority = 0
+    class __metaclass__(type):
+        """Give each ClassRegistry their own registry"""
+        def __init__(cls, name, bases, attrs):
+            cls.registry = {}
+            type.__init__(cls, name, bases, attrs)
+
+    def __init__(cls, name, bases, attrs):
+        super(ClassRegistry, cls).__init__(name, bases, attrs)
+        try:
+            if not cls.implemented:
+                return
+        except AttributeError:
+            pass
+
+        try:
+            cls.name
+        except AttributeError:
+            cls.name = name
+        cls.registry[cls.name] = cls
+
+    @classmethod
+    def prioritized(tcls):
+        return sorted(tcls.registry.values(),
+                      key=lambda v: v.priority, reverse=True)
+
+    def unregister(cls):
+        for key in cls.registry.keys():
+            if cls.registry[key] is cls:
+                del cls.registry[key]

1.7.1

From: Chris Larson <[email protected]>

In the new implementation, each known terminal is defined as a class in oe.terminal, as a subclass of bb.process.Popen. It obeys the OE_TERMINAL variable, which is a 'choice' typed variable. This variable may be 'auto', 'none', or any of the names of the defined terminals.

When using 'auto', or requesting an unsupported terminal, we attempt to spawn them in priority order until we get one that's available on this system (and in the case of the X terminals, has DISPLAY defined). The 'none' value is used when we're doing things like automated builds, and want to ensure that no terminal is *ever* spawned, under any circumstances.

Current available terminals:

gnome
konsole
xterm
rxvt
screen

---
 meta/classes/devshell.bbclass |   25 ++------
 meta/conf/bitbake.conf        |    9 +++
 meta/lib/oe/classutils.py     |    2 +
 meta/lib/oe/terminal.py       |  126 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 143 insertions(+), 19 deletions(-)
 create mode 100644 meta/lib/oe/terminal.py

index 5f262f4..216a9dc 100644
@@ -1,22 +1,9 @@
-do_devshell[dirs] = "${S}"
-do_devshell[nostamp] = "1"
-
-XAUTHORITY ?= "${HOME}/.Xauthority"
-
-devshell_do_devshell() {
-	export DISPLAY='${DISPLAY}'
-	export DBUS_SESSION_BUS_ADDRESS='${DBUS_SESSION_BUS_ADDRESS}'
-	export XAUTHORITY='${XAUTHORITY}'
-	export TERMWINDOWTITLE="Bitbake Developer Shell"
-	export EXTRA_OEMAKE='${EXTRA_OEMAKE}'
-	export SHELLCMDS="bash"
-	${TERMCMDRUN}
-	if [ $? -ne 0 ]; then
-	    echo "Fatal: '${TERMCMD}' not found. Check TERMCMD variable."
-	    exit 1
-	fi
+python do_devshell () {
+    import oe.terminal
+    oe.terminal.run(d.getVar('SHELL', True), 'OpenEmbedded Developer Shell', d)
 }
-addtask devshell after do_patch
 
-EXPORT_FUNCTIONS do_devshell
+addtask devshell after do_patch
 
+do_devshell[dirs] = "${S}"
+do_devshell[nostamp] = "1"

index a0af672..45a426d 100644
@@ -539,6 +539,15 @@ PREFERRED_PROVIDER_virtual/fakeroot-native ?= "pseudo-native"
 # UI/Interaction Configuration
 ##################################################################
 
+
+OE_TERMINAL ?= 'auto'
+OE_TERMINAL[type] = 'choice'
+OE_TERMINAL[choices] = 'auto none \
+                        ${@" ".join(o.name \
+                                    for o in oe.terminal.prioritized())}'
+
+export XAUTHORITY ?= "${HOME}/.Xauthority"
+export SHELL ?= "bash"
 export SHELLCMDS = "bash"
 # Some common terminal programs to choose from
 GNOME_TERMCMD = 'gnome-terminal --disable-factory -t "$TERMWINDOWTITLE"'

index 58188fd..42b0f49 100644
@@ -1,3 +1,5 @@
+__author__ = 'kergoth'
+
 class ClassRegistry(type):
     """Maintain a registry of classes, indexed by name.
 

1.7.1

From: Chris Larson <[email protected]>

- Name the screen session 'devshell', to avoid confusion if running bitbake itself under a screen session.
- Display a warning message when spawning screen, so it's clear to the user that screen has been run (otherwise do_devshell just appears to hang).

---
 meta/lib/oe/terminal.py |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

index e14fc5d..4fd281c 100644
@@ -74,7 +74,12 @@ class Rxvt(XTerminal):
     priority = 1
 
 class Screen(Terminal):
-    command = 'screen -D -m -t "{title}" {command}'
+    command = 'screen -D -m -t "{title}" -S devshell {command}'
+
+    def __init__(self, command, title=None):
+        Terminal.__init__(self, command, title)
+        logger.warn('Screen started. Please connect in another terminal with '
+                    '"screen -r devshell"')
 
 
 def prioritized():

1.7.1

I like this series!

Speaking of devshell, last I tried (and Paul E can correct me here) Konsole doesn't wait when it's spawned so is currently pretty useless for devshell (bitbake continues as if the devshell had finished and if a patch hasn't applied....).

Perhaps we should remove support for it from the class? Or is there some better way we can work around this?

As an aside: I think somewhere in meta-yocto, to maintain current behaviour we'd want to set: OE_TERMINAL ?= 'Gnome' to maintain gnome-terminal as the default (when installed).

Cheers,
Joshua

Joshua Lock
        Yocto Project Build Monkey
        Intel Open Source Technology Centre

I can confirm this - right now our Konsole support just does not work and I imagine it has not since KDE 4.0. Adding the --nofork command line option which is supposed to make it wait does not work either, because if the controlling terminal is not interactive it assumes there is no other instance of Konsole running, tries to register a DBUS service and fails (and it's hard to imagine someone using KDE and running bitbake without having an instance of Konsole running already).

A while ago I had a look adding a command line option to Konsole itself to make this work but didn't get very far, although I don't think it should be too difficult. There is a workaround script [1] but when I tried it just now I found it again has problems if the controlling terminal is not interactive (never returns). Frankly the script is hideous and maybe it was broken in a version of KDE since the script was written, I don't know.

It might be prudent to remove the Konsole support until it has been fixed appropriately; at the very least it should be documented to only work with Konsole from KDE 3.x.

FYI the "workaround" I use here for the moment (if I don't just disable the feature with PATCHRESOLVE = "noop") is to use xterm instead of Konsole for TERMCMD and TERMCMDRUN.

Cheers,
Paul

[1] http://lists.kde.org/?l=kde-core-devel&m=123188146810950&w=2