[PATCH 0/3][v2] Rework the devshell

[PATCH 0/3][v2] Rework the devshell

[Chris Larson]

From: Chris Larson <chris_larson@mentor.com>

- 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

Pull URL: https://github.com/kergoth/oe-core
  Branch: devshell
  Browse: https://github.com/kergoth/oe-core/commits/devshell

Thanks,
    Chris Larson <chris_larson@mentor.com>
---


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

 meta/classes/devshell.bbclass |   26 ++++-------
 meta/classes/terminal.bbclass |   30 +++++++++++
 meta/lib/oe/classutils.py     |   45 +++++++++++++++++
 meta/lib/oe/terminal.py       |  107 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 191 insertions(+), 17 deletions(-)
 create mode 100644 meta/classes/terminal.bbclass
 create mode 100644 meta/lib/oe/classutils.py
 create mode 100644 meta/lib/oe/terminal.py

-- 
1.7.4.1

[PATCH 1/3] oe.classutils: add module

[Chris Larson]

From: Chris Larson <chris_larson@mentor.com>

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

Signed-off-by: Chris Larson <chris_larson@mentor.com>
---
 meta/lib/oe/classutils.py |   24 ++++++++++++++++++++++++
 1 files changed, 24 insertions(+), 0 deletions(-)
 create mode 100644 meta/lib/oe/classutils.py

diff --git a/meta/lib/oe/classutils.py b/meta/lib/oe/classutils.py
new file mode 100644
index 0000000..855d2fa
--- /dev/null
+++ b/meta/lib/oe/classutils.py
@@ -0,0 +1,24 @@
+class ClassRegistry(type):
+    """Maintain a registry of classes, indexed 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."""
+    registry = {}
+    priority = 0
+
+    def __init__(cls, name, bases, attrs):
+        super(ClassRegistry, cls).__init__(name, bases, attrs)
+        if not hasattr(cls, name):
+            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]
-- 
1.7.4.1

[PATCH 2/3] Rework how the devshell functions

[Chris Larson]

From: Chris Larson <chris_larson@mentor.com>

In the new implementation, each known terminal is defined as a class in
oe.terminal, as a subclass of bb.process.Popen.  terminal.bbclass wraps this
functionality, providing the metadata pieces.  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

Signed-off-by: Chris Larson <chris_larson@mentor.com>
---
 meta/classes/devshell.bbclass |   26 ++++-------
 meta/classes/terminal.bbclass |   30 ++++++++++++
 meta/lib/oe/classutils.py     |   33 +++++++++++--
 meta/lib/oe/terminal.py       |  102 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 168 insertions(+), 23 deletions(-)
 create mode 100644 meta/classes/terminal.bbclass
 create mode 100644 meta/lib/oe/terminal.py

diff --git a/meta/classes/devshell.bbclass b/meta/classes/devshell.bbclass
index 5f262f4..7317d64 100644
--- a/meta/classes/devshell.bbclass
+++ b/meta/classes/devshell.bbclass
@@ -1,22 +1,14 @@
-do_devshell[dirs] = "${S}"
-do_devshell[nostamp] = "1"
+inherit terminal
 
-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
+export XAUTHORITY ?= "${HOME}/.Xauthority"
+export SHELL ?= 'bash'
+
+python do_devshell () {
+    oe_terminal(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"
diff --git a/meta/classes/terminal.bbclass b/meta/classes/terminal.bbclass
new file mode 100644
index 0000000..93646f7
--- /dev/null
+++ b/meta/classes/terminal.bbclass
@@ -0,0 +1,30 @@
+OE_TERMINAL ?= 'auto'
+OE_TERMINAL[type] = 'choice'
+OE_TERMINAL[choices] = 'auto none \
+                        ${@" ".join(o.name \
+                                    for o in oe.terminal.prioritized())}'
+
+
+def oe_terminal(command, title, d):
+    import oe.data
+    import oe.terminal
+
+    terminal = oe.data.typed_value('OE_TERMINAL', d).lower()
+    if terminal == 'none':
+        bb.fatal('Devshell usage disabled with OE_TERMINAL')
+    elif terminal != 'auto':
+        try:
+            oe.terminal.spawn(terminal, command, title)
+            return
+        except oe.terminal.UnsupportedTerminal:
+            bb.warn('Unsupported terminal "%s", defaulting to "auto"' %
+                    terminal)
+        except oe.terminal.ExecutionError as exc:
+            bb.fatal('Unable to spawn terminal %s: %s' % (terminal, exc))
+
+    try:
+        oe.terminal.spawn_preferred(command, title)
+    except oe.terminal.NoSupportedTerminals:
+        bb.fatal('No valid terminal found, unable to open devshell')
+    except oe.terminal.ExecutionError as exc:
+        bb.fatal('Unable to spawn terminal %s: %s' % (terminal, exc))
diff --git a/meta/lib/oe/classutils.py b/meta/lib/oe/classutils.py
index 855d2fa..922d304 100644
--- a/meta/lib/oe/classutils.py
+++ b/meta/lib/oe/classutils.py
@@ -1,15 +1,36 @@
+__author__ = 'kergoth'
+
 class ClassRegistry(type):
     """Maintain a registry of classes, indexed 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."""
-    registry = {}
+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)
-        if not hasattr(cls, name):
+        try:
+            if not cls.implemented:
+                return
+        except AttributeError:
+            pass
+
+        try:
+            cls.name
+        except AttributeError:
             cls.name = name
         cls.registry[cls.name] = cls
 
@@ -21,4 +42,4 @@ class ClassRegistry(type):
     def unregister(cls):
         for key in cls.registry.keys():
             if cls.registry[key] is cls:
-                del cls.registry[key]
+                del cls.registry[key]
\ No newline at end of file
diff --git a/meta/lib/oe/terminal.py b/meta/lib/oe/terminal.py
new file mode 100644
index 0000000..5336167
--- /dev/null
+++ b/meta/lib/oe/terminal.py
@@ -0,0 +1,102 @@
+import logging
+import os
+import oe.classutils
+import shlex
+from bb.process import Popen, ExecutionError
+
+logger = logging.getLogger('BitBake.OE.Terminal')
+
+
+class UnsupportedTerminal(StandardError):
+    pass
+
+class NoSupportedTerminals(StandardError):
+    pass
+
+
+class Registry(oe.classutils.ClassRegistry):
+    command = None
+
+    def __init__(cls, name, bases, attrs):
+        super(Registry, cls).__init__(name.lower(), bases, attrs)
+
+    @property
+    def implemented(cls):
+        return bool(cls.command)
+
+
+class Terminal(Popen):
+    __metaclass__ = Registry
+
+    def __init__(self, command, title=None):
+        self.format_command(command, title)
+        logger.debug(1, "%s: running %s", self.name, self.command)
+
+        try:
+            Popen.__init__(self, self.command, shell=False)
+        except OSError as exc:
+            import errno
+            if exc.errno == errno.ENOENT:
+                raise UnsupportedTerminal(self.name)
+            else:
+                raise
+
+    def format_command(self, command, title):
+        fmt = {'title': title or 'Terminal', 'command': command}
+        if isinstance(self.command, basestring):
+            self.command = shlex.split(self.command.format(**fmt))
+        else:
+            self.command = [element.format(**fmt) for element in self.command]
+
+class XTerminal(Terminal):
+    def __init__(self, command, title=None):
+        Terminal.__init__(self, command, title)
+        if not os.environ.get('DISPLAY'):
+            raise UnsupportedTerminal(self.name)
+
+class Gnome(XTerminal):
+    command = 'gnome-terminal --disable-factory -t "{title}" -x {command}'
+    priority = 2
+
+class Konsole(XTerminal):
+    command = 'konsole -T "{title}" -e {command}'
+    priority = 2
+
+class XTerm(XTerminal):
+    command = 'xterm -T "{title}" -e {command}'
+    priority = 1
+
+class Rxvt(XTerminal):
+    command = 'rxvt -T "{title}" -e {command}'
+    priority = 1
+
+class Screen(Terminal):
+    command = 'screen -D -m -t "{title}" {command}'
+
+
+def prioritized():
+    return Registry.prioritized()
+
+def spawn_preferred(command, title=None):
+    """Spawn the first supported terminal, by priority"""
+    for terminal in prioritized():
+        try:
+            spawn(terminal.name, command, title)
+            break
+        except UnsupportedTerminal:
+            continue
+    else:
+        raise NoSupportedTerminals()
+
+def spawn(name, command, title=None):
+    """Spawn the specified terminal, by name"""
+    logger.debug(1, 'Attempting to spawn terminal "%s"', name)
+    try:
+        terminal = Registry.registry[name]
+    except KeyError:
+        raise UnsupportedTerminal(name)
+
+    pipe = terminal(command, title)
+    output = pipe.communicate()[0]
+    if pipe.returncode != 0:
+        raise ExecutionError(pipe.command, pipe.returncode, output)
-- 
1.7.4.1

[PATCH 3/3] oe.terminal: improve how we spawn screen

[Chris Larson]

From: Chris Larson <chris_larson@mentor.com>

- 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).

Signed-off-by: Chris Larson <chris_larson@mentor.com>
---
 meta/lib/oe/terminal.py |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/meta/lib/oe/terminal.py b/meta/lib/oe/terminal.py
index 5336167..bbff8d0 100644
--- a/meta/lib/oe/terminal.py
+++ b/meta/lib/oe/terminal.py
@@ -71,7 +71,12 @@ 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():
-- 
1.7.4.1

Re: [PATCH 0/3][v2] Rework the devshell

[Khem Raj]

On 4/5/2011 1:30 PM, Chris Larson wrote:
> From: Chris Larson<chris_larson@mentor.com>
>
> - 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
>


works nicely. I usually use screen and it helped

> Pull URL: https://github.com/kergoth/oe-core
>    Branch: devshell
>    Browse: https://github.com/kergoth/oe-core/commits/devshell
>
> Thanks,
>      Chris Larson<chris_larson@mentor.com>
> ---
>
>
> Chris Larson (3):
>    oe.classutils: add module
>    Rework how the devshell functions
>    oe.terminal: improve how we spawn screen
>
>   meta/classes/devshell.bbclass |   26 ++++-------
>   meta/classes/terminal.bbclass |   30 +++++++++++
>   meta/lib/oe/classutils.py     |   45 +++++++++++++++++
>   meta/lib/oe/terminal.py       |  107 +++++++++++++++++++++++++++++++++++++++++
>   4 files changed, 191 insertions(+), 17 deletions(-)
>   create mode 100644 meta/classes/terminal.bbclass
>   create mode 100644 meta/lib/oe/classutils.py
>   create mode 100644 meta/lib/oe/terminal.py
>