"""
Alternatives - command ``/usr/bin/alternatives`` output
=======================================================
"""
from insights import parser, CommandParser
from insights.core.exceptions import ParseException
from insights.specs import Specs
[docs]
class AlternativesOutput(CommandParser):
"""
Read the output of ``/usr/sbin/alternatives --display *program*`` and
convert into information about the given program's alternatives.
Typical input is::
java - status is auto.
link currently points to /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.111-1.b15.el7_2.x86_64/jre/bin/java
/usr/lib/jvm/java-1.7.0-openjdk-1.7.0.111-2.6.7.2.el7_2.x86_64/jre/bin/java - priority 1700111
/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.111-1.b15.el7_2.x86_64/jre/bin/java - priority 1800111
/usr/lib/jvm/jre-1.6.0-ibm.x86_64/bin/java - priority 16091
slave ControlPanel: /usr/lib/jvm/jre-1.6.0-ibm.x86_64/bin/ControlPanel
slave keytool: /usr/lib/jvm/jre-1.6.0-ibm.x86_64/bin/keytool
slave policytool: /usr/lib/jvm/jre-1.6.0-ibm.x86_64/bin/policytool
slave rmid: /usr/lib/jvm/jre-1.6.0-ibm.x86_64/bin/rmid
Current `best' version is /usr/lib/jvm/jre-1.6.0-ibm.x86_64/bin/java.
Lines are interpreted this way:
* Program lines are of the form '*name* - status is *status*', and start
the information for a program. Lines before this are ignored.
* The current link to this program is found on lines starting with 'link
currently points to'.
* Lines starting with '/' and with ' - priority ' in them record an
alternative path and its priority.
* Lines starting with 'slave *program*: *path*' are recorded against the
alternative path.
* Lines starting with 'Current \`best' version is' indicate the default
choice of an 'auto' status alternative.
The output of ``alternatives --display *program*`` can only ever list one
program, so as long as one 'status is' line is found (as described above),
the content of the object displays that program.
Attributes:
program (str): The name of the program found in the 'status is' line.
This attribute is set to ``None`` if a status line is not found.
status (str): The status of the program, or ``None`` if not found.
link (str): The link to this program, or ``None`` if the 'link
currently points to`` line is not found.
best (str): The 'best choice' path that ``alternatives`` would use, or
``None`` if the 'best choice' line is not found.
paths (dict): The alternative paths for this program. Each path is a
dictionary containing the following keys:
* ``path``: the actual path of this alternative for the program
* ``priority``: the priority, as an integer (e.g. 1700111)
* ``slave``: a dictionary of programs dependent on this alternative -
the key is the program name (e.g. 'ControlPanel') and the value is
the path to that program for this alternative path.
Examples:
>>> java_alt.program
'java'
>>> java_alt.link
'/usr/lib/jvm/jre-1.6.0-ibm.x86_64/bin/java'
>>> len(java_alt.paths)
2
>>> java_alt.paths[0]['path']
'/usr/lib/jvm/jre-1.6.0-ibm.x86_64/bin/java'
>>> java_alt.paths[0]['priority']
16091
>>> java_alt.paths[0]['slave']['ControlPanel']
'/usr/lib/jvm/jre-1.6.0-ibm.x86_64/bin/ControlPanel'
"""
[docs]
def parse_content(self, content):
"""
Parse the output of the ``alternatives`` command.
"""
self.program = None
self.status = None
self.link = None
self.best = None
self.paths = []
current_path = None
# Set up instance variable
for line in content:
words = line.split(None)
if ' - status is' in line:
# alternatives only displays one program, so finding
# this line again is an error.
if self.program:
raise ParseException(
"Program line for {newprog} found in output for {oldprog}".format(
newprog=words[0], oldprog=self.program
)
)
# Set up new program data
self.program = words[0]
self.status = words[4][:-1] # remove trailing .
self.alternatives = []
current_path = {}
elif not self.program:
# Lines before 'status is' line are ignored
continue
elif line.startswith(' link currently points to ') and len(words) == 5:
# line: ' link currently points to /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.111-1.b15.el7_2.x86_64/jre/bin/java'
self.link = words[4]
elif ' - priority ' in line and len(words) == 4 and words[3].isdigit():
# line: /usr/lib/jvm/jre-1.6.0-ibm.x86_64/bin/java - priority 16091
# New path - save current path if set
self.paths.append({
'path': words[0],
'priority': int(words[3]),
'slave': {},
})
current_path = self.paths[-1]
elif line.startswith(' slave ') and len(words) == 3 and current_path:
# line: ' slave ControlPanel: /usr/lib/jvm/jre-1.6.0-ibm.x86_64/bin/ControlPanel'
current_path['slave'][words[1][:-1]] = words[2] # remove final : from program
elif line.startswith("Current `best' version is ") and len(words) == 5:
# line: 'Current `best' version is /usr/lib/jvm/jre-1.6.0-ibm.x86_64/bin/java.'
self.best = words[4][:-1] # strip trailing . from path
[docs]
@parser(Specs.display_java)
class JavaAlternatives(AlternativesOutput):
"""
Class to read the ``/usr/sbin/alternatives --display java`` output.
Uses the ``AlternativesOutput`` base class to get information about the
alternatives for ``java`` available and which one is currently in use.
Examples:
>>> java_alt.program
'java'
>>> java_alt.link
'/usr/lib/jvm/jre-1.6.0-ibm.x86_64/bin/java'
>>> len(java_alt.paths)
2
>>> java_alt.paths[0]['path']
'/usr/lib/jvm/jre-1.6.0-ibm.x86_64/bin/java'
>>> java_alt.paths[0]['priority']
16091
>>> java_alt.paths[0]['slave']['ControlPanel']
'/usr/lib/jvm/jre-1.6.0-ibm.x86_64/bin/ControlPanel'
"""
pass
[docs]
@parser(Specs.alternatives_display_python)
class PythonAlternatives(AlternativesOutput):
"""
Class to read the ``/usr/sbin/alternatives --display python`` output.
Uses the ``AlternativesOutput`` base class to get information about the
alternatives for ``best`` available and which one is currently in use.
Examples:
>>> python_alt.program
'python'
>>> python_alt.link
'/usr/bin/python3'
>>> len(python_alt.paths)
2
>>> python_alt.paths[0]['path']
'/usr/libexec/no-python'
>>> python_alt.paths[0]['priority']
404
"""
pass