| # Copyright 2009 Google Inc. Released under the GPL v2 |
| |
| """ |
| This module defines the base classes for the Host hierarchy. |
| |
| Implementation details: |
| You should import the "hosts" package instead of importing each type of host. |
| |
| Host: a machine on which you can run programs |
| """ |
| |
| __author__ = """ |
| mbligh@google.com (Martin J. Bligh), |
| poirier@google.com (Benjamin Poirier), |
| stutsman@google.com (Ryan Stutsman) |
| """ |
| |
| import cPickle, logging, os, re, time |
| |
| from autotest_lib.client.common_lib import global_config, error, utils |
| from autotest_lib.client.common_lib.cros import path_utils |
| from autotest_lib.client.common_lib.cros.graphite import autotest_stats |
| |
| |
| class Host(object): |
| """ |
| This class represents a machine on which you can run programs. |
| |
| It may be a local machine, the one autoserv is running on, a remote |
| machine or a virtual machine. |
| |
| Implementation details: |
| This is an abstract class, leaf subclasses must implement the methods |
| listed here. You must not instantiate this class but should |
| instantiate one of those leaf subclasses. |
| |
| When overriding methods that raise NotImplementedError, the leaf class |
| is fully responsible for the implementation and should not chain calls |
| to super. When overriding methods that are a NOP in Host, the subclass |
| should chain calls to super(). The criteria for fitting a new method into |
| one category or the other should be: |
| 1. If two separate generic implementations could reasonably be |
| concatenated, then the abstract implementation should pass and |
| subclasses should chain calls to super. |
| 2. If only one class could reasonably perform the stated function |
| (e.g. two separate run() implementations cannot both be executed) |
| then the method should raise NotImplementedError in Host, and |
| the implementor should NOT chain calls to super, to ensure that |
| only one implementation ever gets executed. |
| """ |
| |
| job = None |
| DEFAULT_REBOOT_TIMEOUT = global_config.global_config.get_config_value( |
| "HOSTS", "default_reboot_timeout", type=int, default=1800) |
| WAIT_DOWN_REBOOT_TIMEOUT = global_config.global_config.get_config_value( |
| "HOSTS", "wait_down_reboot_timeout", type=int, default=840) |
| WAIT_DOWN_REBOOT_WARNING = global_config.global_config.get_config_value( |
| "HOSTS", "wait_down_reboot_warning", type=int, default=540) |
| HOURS_TO_WAIT_FOR_RECOVERY = global_config.global_config.get_config_value( |
| "HOSTS", "hours_to_wait_for_recovery", type=float, default=2.5) |
| # the number of hardware repair requests that need to happen before we |
| # actually send machines to hardware repair |
| HARDWARE_REPAIR_REQUEST_THRESHOLD = 4 |
| OP_REBOOT = 'reboot' |
| OP_SUSPEND = 'suspend' |
| PWR_OPERATION = [OP_REBOOT, OP_SUSPEND] |
| |
| |
| def __init__(self, *args, **dargs): |
| self._initialize(*args, **dargs) |
| |
| |
| def _initialize(self, *args, **dargs): |
| pass |
| |
| |
| @property |
| def job_repo_url_attribute(self): |
| """Get the host attribute name for job_repo_url. |
| """ |
| return 'job_repo_url' |
| |
| |
| def close(self): |
| """Close the connection to the host. |
| """ |
| pass |
| |
| |
| def setup(self): |
| """Setup the host object. |
| """ |
| pass |
| |
| |
| def run(self, command, timeout=3600, ignore_status=False, |
| stdout_tee=utils.TEE_TO_LOGS, stderr_tee=utils.TEE_TO_LOGS, |
| stdin=None, args=()): |
| """ |
| Run a command on this host. |
| |
| @param command: the command line string |
| @param timeout: time limit in seconds before attempting to |
| kill the running process. The run() function |
| will take a few seconds longer than 'timeout' |
| to complete if it has to kill the process. |
| @param ignore_status: do not raise an exception, no matter |
| what the exit code of the command is. |
| @param stdout_tee: where to tee the stdout |
| @param stderr_tee: where to tee the stderr |
| @param stdin: stdin to pass (a string) to the executed command |
| @param args: sequence of strings to pass as arguments to command by |
| quoting them in " and escaping their contents if necessary |
| |
| @return a utils.CmdResult object |
| |
| @raises AutotestHostRunError: the exit code of the command execution |
| was not 0 and ignore_status was not enabled |
| """ |
| raise NotImplementedError('Run not implemented!') |
| |
| |
| def run_output(self, command, *args, **dargs): |
| """Run and retrieve the value of stdout stripped of whitespace. |
| |
| @param command: Command to execute. |
| @param *args: Extra arguments to run. |
| @param **dargs: Extra keyword arguments to run. |
| |
| @return: String value of stdout. |
| """ |
| return self.run(command, *args, **dargs).stdout.rstrip() |
| |
| |
| def reboot(self): |
| """Reboot the host. |
| """ |
| raise NotImplementedError('Reboot not implemented!') |
| |
| |
| def suspend(self): |
| """Suspend the host. |
| """ |
| raise NotImplementedError('Suspend not implemented!') |
| |
| |
| def sysrq_reboot(self): |
| """Execute host reboot via SysRq key. |
| """ |
| raise NotImplementedError('Sysrq reboot not implemented!') |
| |
| |
| def reboot_setup(self, *args, **dargs): |
| """Prepare for reboot. |
| |
| This doesn't appear to be implemented by any current hosts. |
| |
| @param *args: Extra arguments to ?. |
| @param **dargs: Extra keyword arguments to ?. |
| """ |
| pass |
| |
| |
| def reboot_followup(self, *args, **dargs): |
| """Post reboot work. |
| |
| This doesn't appear to be implemented by any current hosts. |
| |
| @param *args: Extra arguments to ?. |
| @param **dargs: Extra keyword arguments to ?. |
| """ |
| pass |
| |
| |
| def get_file(self, source, dest, delete_dest=False): |
| """Retrieve a file from the host. |
| |
| @param source: Remote file path (directory, file or list). |
| @param dest: Local file path (directory, file or list). |
| @param delete_dest: Delete files in remote path that are not in local |
| path. |
| """ |
| raise NotImplementedError('Get file not implemented!') |
| |
| |
| def send_file(self, source, dest, delete_dest=False): |
| """Send a file to the host. |
| |
| @param source: Local file path (directory, file or list). |
| @param dest: Remote file path (directory, file or list). |
| @param delete_dest: Delete files in remote path that are not in local |
| path. |
| """ |
| raise NotImplementedError('Send file not implemented!') |
| |
| |
| def get_tmp_dir(self): |
| """Create a temporary directory on the host. |
| """ |
| raise NotImplementedError('Get temp dir not implemented!') |
| |
| |
| def is_up(self): |
| """Confirm the host is online. |
| """ |
| raise NotImplementedError('Is up not implemented!') |
| |
| |
| def is_shutting_down(self): |
| """ Indicates is a machine is currently shutting down. """ |
| return False |
| |
| |
| def get_wait_up_processes(self): |
| """ Gets the list of local processes to wait for in wait_up. """ |
| get_config = global_config.global_config.get_config_value |
| proc_list = get_config("HOSTS", "wait_up_processes", |
| default="").strip() |
| processes = set(p.strip() for p in proc_list.split(",")) |
| processes.discard("") |
| return processes |
| |
| |
| def get_boot_id(self, timeout=60): |
| """ Get a unique ID associated with the current boot. |
| |
| Should return a string with the semantics such that two separate |
| calls to Host.get_boot_id() return the same string if the host did |
| not reboot between the two calls, and two different strings if it |
| has rebooted at least once between the two calls. |
| |
| @param timeout The number of seconds to wait before timing out. |
| |
| @return A string unique to this boot or None if not available.""" |
| BOOT_ID_FILE = '/proc/sys/kernel/random/boot_id' |
| NO_ID_MSG = 'no boot_id available' |
| cmd = 'if [ -f %r ]; then cat %r; else echo %r; fi' % ( |
| BOOT_ID_FILE, BOOT_ID_FILE, NO_ID_MSG) |
| boot_id = self.run(cmd, timeout=timeout).stdout.strip() |
| if boot_id == NO_ID_MSG: |
| return None |
| return boot_id |
| |
| |
| def wait_up(self, timeout=None): |
| """Wait for the host to come up. |
| |
| @param timeout: Max seconds to wait. |
| """ |
| raise NotImplementedError('Wait up not implemented!') |
| |
| |
| def wait_down(self, timeout=None, warning_timer=None, old_boot_id=None): |
| """Wait for the host to go down. |
| |
| @param timeout: Max seconds to wait before returning. |
| @param warning_timer: Seconds before warning host is not down. |
| @param old_boot_id: Result of self.get_boot_id() before shutdown. |
| """ |
| raise NotImplementedError('Wait down not implemented!') |
| |
| |
| def _construct_host_metadata(self, type_str): |
| """Returns dict of metadata with type_str, hostname, time_recorded. |
| |
| @param type_str: String representing _type field in es db. |
| For example: type_str='reboot_total'. |
| """ |
| metadata = { |
| 'hostname': self.hostname, |
| 'time_recorded': time.time(), |
| '_type': type_str, |
| } |
| return metadata |
| |
| |
| def wait_for_restart(self, timeout=DEFAULT_REBOOT_TIMEOUT, |
| down_timeout=WAIT_DOWN_REBOOT_TIMEOUT, |
| down_warning=WAIT_DOWN_REBOOT_WARNING, |
| log_failure=True, old_boot_id=None, **dargs): |
| """Wait for the host to come back from a reboot. |
| |
| This is a generic implementation based entirely on wait_up and |
| wait_down. |
| |
| @param timeout: Max seconds to wait for reboot to start. |
| @param down_timeout: Max seconds to wait for host to go down. |
| @param down_warning: Seconds to wait before warning host hasn't gone |
| down. |
| @param log_failure: bool(Log when host does not go down.) |
| @param old_boot_id: Result of self.get_boot_id() before restart. |
| @param **dargs: Extra arguments to reboot_followup. |
| |
| @raises AutoservRebootError if host does not come back up. |
| """ |
| key_string = 'Reboot.%s' % dargs.get('board') |
| |
| total_reboot_timer = autotest_stats.Timer('%s.total' % key_string, |
| metadata=self._construct_host_metadata('reboot_total')) |
| wait_down_timer = autotest_stats.Timer('%s.wait_down' % key_string, |
| metadata=self._construct_host_metadata('reboot_down')) |
| |
| total_reboot_timer.start() |
| wait_down_timer.start() |
| if not self.wait_down(timeout=down_timeout, |
| warning_timer=down_warning, |
| old_boot_id=old_boot_id): |
| if log_failure: |
| self.record("ABORT", None, "reboot.verify", "shut down failed") |
| raise error.AutoservShutdownError("Host did not shut down") |
| wait_down_timer.stop() |
| wait_up_timer = autotest_stats.Timer('%s.wait_up' % key_string, |
| metadata=self._construct_host_metadata('reboot_up')) |
| wait_up_timer.start() |
| if self.wait_up(timeout): |
| self.record("GOOD", None, "reboot.verify") |
| self.reboot_followup(**dargs) |
| wait_up_timer.stop() |
| total_reboot_timer.stop() |
| else: |
| self.record("ABORT", None, "reboot.verify", |
| "Host did not return from reboot") |
| raise error.AutoservRebootError("Host did not return from reboot") |
| |
| |
| def verify(self): |
| """Check if host is in good state. |
| """ |
| self.verify_hardware() |
| self.verify_connectivity() |
| self.verify_software() |
| |
| |
| def verify_hardware(self): |
| """Check host hardware. |
| """ |
| pass |
| |
| |
| def verify_connectivity(self): |
| """Check host network connectivity. |
| """ |
| pass |
| |
| |
| def verify_software(self): |
| """Check host software. |
| """ |
| pass |
| |
| |
| def check_diskspace(self, path, gb): |
| """Raises an error if path does not have at least gb GB free. |
| |
| @param path The path to check for free disk space. |
| @param gb A floating point number to compare with a granularity |
| of 1 MB. |
| |
| 1000 based SI units are used. |
| |
| @raises AutoservDiskFullHostError if path has less than gb GB free. |
| """ |
| one_mb = 10 ** 6 # Bytes (SI unit). |
| mb_per_gb = 1000.0 |
| logging.info('Checking for >= %s GB of space under %s on machine %s', |
| gb, path, self.hostname) |
| df = self.run('df -PB %d %s | tail -1' % (one_mb, path)).stdout.split() |
| free_space_gb = int(df[3]) / mb_per_gb |
| if free_space_gb < gb: |
| raise error.AutoservDiskFullHostError(path, gb, free_space_gb) |
| else: |
| logging.info('Found %s GB >= %s GB of space under %s on machine %s', |
| free_space_gb, gb, path, self.hostname) |
| |
| |
| def check_inodes(self, path, min_kilo_inodes): |
| """Raises an error if a file system is short on i-nodes. |
| |
| @param path The path to check for free i-nodes. |
| @param min_kilo_inodes Minimum number of i-nodes required, |
| in units of 1000 i-nodes. |
| |
| @raises AutoservNoFreeInodesError If the minimum required |
| i-node count isn't available. |
| """ |
| min_inodes = 1000 * min_kilo_inodes |
| logging.info('Checking for >= %d i-nodes under %s ' |
| 'on machine %s', min_inodes, path, self.hostname) |
| df = self.run('df -Pi %s | tail -1' % path).stdout.split() |
| free_inodes = int(df[3]) |
| if free_inodes < min_inodes: |
| raise error.AutoservNoFreeInodesError(path, min_inodes, |
| free_inodes) |
| else: |
| logging.info('Found %d >= %d i-nodes under %s on ' |
| 'machine %s', free_inodes, min_inodes, |
| path, self.hostname) |
| |
| |
| def erase_dir_contents(self, path, ignore_status=True, timeout=3600): |
| """Empty a given directory path contents. |
| |
| @param path: Path to empty. |
| @param ignore_status: Ignore the exit status from run. |
| @param timeout: Max seconds to allow command to complete. |
| """ |
| rm_cmd = 'find "%s" -mindepth 1 -maxdepth 1 -print0 | xargs -0 rm -rf' |
| self.run(rm_cmd % path, ignore_status=ignore_status, timeout=timeout) |
| |
| |
| def repair(self): |
| """Try and get the host to pass `self.verify()`.""" |
| self.verify() |
| |
| |
| def disable_ipfilters(self): |
| """Allow all network packets in and out of the host.""" |
| self.run('iptables-save > /tmp/iptable-rules') |
| self.run('iptables -P INPUT ACCEPT') |
| self.run('iptables -P FORWARD ACCEPT') |
| self.run('iptables -P OUTPUT ACCEPT') |
| |
| |
| def enable_ipfilters(self): |
| """Re-enable the IP filters disabled from disable_ipfilters()""" |
| if self.path_exists('/tmp/iptable-rules'): |
| self.run('iptables-restore < /tmp/iptable-rules') |
| |
| |
| def cleanup(self): |
| """Restore host to clean state. |
| """ |
| pass |
| |
| |
| def machine_install(self): |
| """Install on the host. |
| """ |
| raise NotImplementedError('Machine install not implemented!') |
| |
| |
| def install(self, installableObject): |
| """Call install on a thing. |
| |
| @param installableObject: Thing with install method that will accept our |
| self. |
| """ |
| installableObject.install(self) |
| |
| |
| def get_autodir(self): |
| raise NotImplementedError('Get autodir not implemented!') |
| |
| |
| def set_autodir(self): |
| raise NotImplementedError('Set autodir not implemented!') |
| |
| |
| def start_loggers(self): |
| """ Called to start continuous host logging. """ |
| pass |
| |
| |
| def stop_loggers(self): |
| """ Called to stop continuous host logging. """ |
| pass |
| |
| |
| # some extra methods simplify the retrieval of information about the |
| # Host machine, with generic implementations based on run(). subclasses |
| # should feel free to override these if they can provide better |
| # implementations for their specific Host types |
| |
| def get_num_cpu(self): |
| """ Get the number of CPUs in the host according to /proc/cpuinfo. """ |
| proc_cpuinfo = self.run('cat /proc/cpuinfo', |
| stdout_tee=open(os.devnull, 'w')).stdout |
| cpus = 0 |
| for line in proc_cpuinfo.splitlines(): |
| if line.startswith('processor'): |
| cpus += 1 |
| return cpus |
| |
| |
| def get_arch(self): |
| """ Get the hardware architecture of the remote machine. """ |
| cmd_uname = path_utils.must_be_installed('/bin/uname', host=self) |
| arch = self.run('%s -m' % cmd_uname).stdout.rstrip() |
| if re.match(r'i\d86$', arch): |
| arch = 'i386' |
| return arch |
| |
| |
| def get_kernel_ver(self): |
| """ Get the kernel version of the remote machine. """ |
| cmd_uname = path_utils.must_be_installed('/bin/uname', host=self) |
| return self.run('%s -r' % cmd_uname).stdout.rstrip() |
| |
| |
| def get_cmdline(self): |
| """ Get the kernel command line of the remote machine. """ |
| return self.run('cat /proc/cmdline').stdout.rstrip() |
| |
| |
| def get_meminfo(self): |
| """ Get the kernel memory info (/proc/meminfo) of the remote machine |
| and return a dictionary mapping the various statistics. """ |
| meminfo_dict = {} |
| meminfo = self.run('cat /proc/meminfo').stdout.splitlines() |
| for key, val in (line.split(':', 1) for line in meminfo): |
| meminfo_dict[key.strip()] = val.strip() |
| return meminfo_dict |
| |
| |
| def path_exists(self, path): |
| """Determine if path exists on the remote machine. |
| |
| @param path: path to check |
| |
| @return: bool(path exists)""" |
| result = self.run('ls "%s" > /dev/null' % utils.sh_escape(path), |
| ignore_status=True) |
| return result.exit_status == 0 |
| |
| |
| # some extra helpers for doing job-related operations |
| |
| def record(self, *args, **dargs): |
| """ Helper method for recording status logs against Host.job that |
| silently becomes a NOP if Host.job is not available. The args and |
| dargs are passed on to Host.job.record unchanged. """ |
| if self.job: |
| self.job.record(*args, **dargs) |
| |
| |
| def log_kernel(self): |
| """ Helper method for logging kernel information into the status logs. |
| Intended for cases where the "current" kernel is not really defined |
| and we want to explicitly log it. Does nothing if this host isn't |
| actually associated with a job. """ |
| if self.job: |
| kernel = self.get_kernel_ver() |
| self.job.record("INFO", None, None, |
| optional_fields={"kernel": kernel}) |
| |
| |
| def log_op(self, op, op_func): |
| """ Decorator for wrapping a management operaiton in a group for status |
| logging purposes. |
| |
| @param op: name of the operation. |
| @param op_func: a function that carries out the operation |
| (reboot, suspend) |
| """ |
| if self.job and not hasattr(self, "RUNNING_LOG_OP"): |
| self.RUNNING_LOG_OP = True |
| try: |
| self.job.run_op(op, op_func, self.get_kernel_ver) |
| finally: |
| del self.RUNNING_LOG_OP |
| else: |
| op_func() |
| |
| |
| def list_files_glob(self, glob): |
| """Get a list of files on a remote host given a glob pattern path. |
| |
| @param glob: pattern |
| |
| @return: list of files |
| """ |
| SCRIPT = ("python -c 'import cPickle, glob, sys;" |
| "cPickle.dump(glob.glob(sys.argv[1]), sys.stdout, 0)'") |
| output = self.run(SCRIPT, args=(glob,), stdout_tee=None, |
| timeout=60).stdout |
| return cPickle.loads(output) |
| |
| |
| def symlink_closure(self, paths): |
| """ |
| Given a sequence of path strings, return the set of all paths that |
| can be reached from the initial set by following symlinks. |
| |
| @param paths: sequence of path strings. |
| @return: a sequence of path strings that are all the unique paths that |
| can be reached from the given ones after following symlinks. |
| """ |
| SCRIPT = ("python -c 'import cPickle, os, sys\n" |
| "paths = cPickle.load(sys.stdin)\n" |
| "closure = {}\n" |
| "while paths:\n" |
| " path = paths.keys()[0]\n" |
| " del paths[path]\n" |
| " if not os.path.exists(path):\n" |
| " continue\n" |
| " closure[path] = None\n" |
| " if os.path.islink(path):\n" |
| " link_to = os.path.join(os.path.dirname(path),\n" |
| " os.readlink(path))\n" |
| " if link_to not in closure.keys():\n" |
| " paths[link_to] = None\n" |
| "cPickle.dump(closure.keys(), sys.stdout, 0)'") |
| input_data = cPickle.dumps(dict((path, None) for path in paths), 0) |
| output = self.run(SCRIPT, stdout_tee=None, stdin=input_data, |
| timeout=60).stdout |
| return cPickle.loads(output) |
| |
| |
| def cleanup_kernels(self, boot_dir='/boot'): |
| """ |
| Remove any kernel image and associated files (vmlinux, system.map, |
| modules) for any image found in the boot directory that is not |
| referenced by entries in the bootloader configuration. |
| |
| @param boot_dir: boot directory path string, default '/boot' |
| """ |
| # find all the vmlinuz images referenced by the bootloader |
| vmlinuz_prefix = os.path.join(boot_dir, 'vmlinuz-') |
| boot_info = self.bootloader.get_entries() |
| used_kernver = [boot['kernel'][len(vmlinuz_prefix):] |
| for boot in boot_info.itervalues()] |
| |
| # find all the unused vmlinuz images in /boot |
| all_vmlinuz = self.list_files_glob(vmlinuz_prefix + '*') |
| used_vmlinuz = self.symlink_closure(vmlinuz_prefix + kernver |
| for kernver in used_kernver) |
| unused_vmlinuz = set(all_vmlinuz) - set(used_vmlinuz) |
| |
| # find all the unused vmlinux images in /boot |
| vmlinux_prefix = os.path.join(boot_dir, 'vmlinux-') |
| all_vmlinux = self.list_files_glob(vmlinux_prefix + '*') |
| used_vmlinux = self.symlink_closure(vmlinux_prefix + kernver |
| for kernver in used_kernver) |
| unused_vmlinux = set(all_vmlinux) - set(used_vmlinux) |
| |
| # find all the unused System.map files in /boot |
| systemmap_prefix = os.path.join(boot_dir, 'System.map-') |
| all_system_map = self.list_files_glob(systemmap_prefix + '*') |
| used_system_map = self.symlink_closure( |
| systemmap_prefix + kernver for kernver in used_kernver) |
| unused_system_map = set(all_system_map) - set(used_system_map) |
| |
| # find all the module directories associated with unused kernels |
| modules_prefix = '/lib/modules/' |
| all_moddirs = [dir for dir in self.list_files_glob(modules_prefix + '*') |
| if re.match(modules_prefix + r'\d+\.\d+\.\d+.*', dir)] |
| used_moddirs = self.symlink_closure(modules_prefix + kernver |
| for kernver in used_kernver) |
| unused_moddirs = set(all_moddirs) - set(used_moddirs) |
| |
| # remove all the vmlinuz files we don't use |
| # TODO: if needed this should become package manager agnostic |
| for vmlinuz in unused_vmlinuz: |
| # try and get an rpm package name |
| rpm = self.run('rpm -qf', args=(vmlinuz,), |
| ignore_status=True, timeout=120) |
| if rpm.exit_status == 0: |
| packages = set(line.strip() for line in |
| rpm.stdout.splitlines()) |
| # if we found some package names, try to remove them |
| for package in packages: |
| self.run('rpm -e', args=(package,), |
| ignore_status=True, timeout=120) |
| # remove the image files anyway, even if rpm didn't |
| self.run('rm -f', args=(vmlinuz,), |
| ignore_status=True, timeout=120) |
| |
| # remove all the vmlinux and System.map files left over |
| for f in (unused_vmlinux | unused_system_map): |
| self.run('rm -f', args=(f,), |
| ignore_status=True, timeout=120) |
| |
| # remove all unused module directories |
| # the regex match should keep us safe from removing the wrong files |
| for moddir in unused_moddirs: |
| self.run('rm -fr', args=(moddir,), ignore_status=True) |
| |
| |
| def get_attributes_to_clear_before_provision(self): |
| """Get a list of attributes to be cleared before machine_install starts. |
| |
| If provision runs in a lab environment, it is necessary to clear certain |
| host attributes for the host in afe_host_attributes table. For example, |
| `job_repo_url` is a devserver url pointed to autotest packages for |
| CrosHost, it needs to be removed before provision starts for tests to |
| run reliably. |
| For ADBHost, the job repo url has a different format, i.e., appended by |
| adb_serial, so this method should be overriden in ADBHost. |
| """ |
| return ['job_repo_url'] |
| |
| |
| def get_platform(self): |
| """Determine the correct platform label for this host. |
| |
| @return: A string representing this host's platform. |
| """ |
| raise NotImplementedError("Get platform not implemented!") |
| |
| |
| def get_labels(self): |
| """Return a list of the labels gathered from the devices connected. |
| |
| @return: A list of strings that denote the labels from all the devices |
| connected. |
| """ |
| raise NotImplementedError("Get labels not implemented!") |
| |
