Rewrite code snippet handling

Each former code snippet has been transformed into a full-fledged python module.
Responses generated by modules are cached in a single ttl-based cache reducing
required CPU-time for subsequent queries drastically.

announce.py

@@ -3,7 +3,7 @@
 import json
 import argparse
 
-from gather import gather_data
+from providers import Provider
 
 parser = argparse.ArgumentParser()
 
@@ -15,7 +15,10 @@
 
 args = parser.parse_args()
 
-print(json.dumps(gather_data(
-    args.directory,
-    {'batadv_dev': args.batman}
-)))
+provider = Provider.from_directory('providers',
+    args.directory)
+
+print(json.dumps(provider.call(
+        {'batadv_dev': args.batman}
+    )
+))

announce.sh

@@ -31,5 +31,5 @@ done
 
 export GZIP="--best"
 
-"${DIR}"/announce.py -d "${DIR}"/nodeinfo.d/ ${BATADV} | gzip | alfred $INTERFACE $SOCKET -s 158
-"${DIR}"/announce.py -d "${DIR}"/statistics.d/ ${BATADV} | gzip | alfred $INTERFACE $SOCKET -s 159
+"${DIR}"/announce.py -d nodeinfo ${BATADV} | gzip | alfred $INTERFACE $SOCKET -s 158
+"${DIR}"/announce.py -d statistics ${BATADV} | gzip | alfred $INTERFACE $SOCKET -s 159

providers/__init__.py

@@ -0,0 +1,157 @@
+import os
+import time
+import traceback
+from util import source_dirs, find_modules
+from importlib import import_module
+
+class DataSource():
+    ''' Base data source, inherited by sources in provider directories
+    '''
+    def cache_ttl(self):
+        ''' Default cache ttl, set to 0 to disable cache
+        '''
+        return 30
+
+    def required_args(self):
+        ''' Returns a list of required argument names
+        '''
+        return []
+
+    def call(self, *args):
+        ''' Override with actual implementation, args contains arguments listed
+            in required_args in order
+        '''
+        raise NotImplementedError()
+
+
+
+def _set_value(node, path, value):
+    ''' Sets a value inside a complex data dictionary.
+        The path Array must have at least one element.
+    '''
+    key = path[0]
+    if len(path) == 1:
+        node[key] = value
+    elif key in node:
+        _set_value(node[key], path[1:], value)
+    else:
+        node[path[0]] = {}
+        _set_value(node[key], path[1:], value)
+
+class SourceCache():
+    ''' Simple singleton-based cache
+    '''
+    class CacheEntry():
+        def __init__(self, key, value, ttl):
+            self.key = key
+            self.value = value
+            self.expiry = time.monotonic() + ttl
+
+        def isvalid(self):
+            return time.time() < self.expiry
+
+    instance = None
+
+    @classmethod
+    def getinstance(cls):
+        if not cls.instance:
+            cls.instance = cls()
+
+        return cls.instance
+
+    def __init__(self):
+        self.cache = {}
+
+    def put(self, key, value, ttl):
+        self.cache[key] = self.CacheEntry(key, value, ttl)
+
+    def has(self, key):
+        return (key in self.cache) and self.cache[key].isvalid()
+
+    def get(self, key):
+        if not self.has(key):
+            return None
+
+        return self.cache[key].value
+
+class InvalidSourceModuleExeption(Exception):
+    def __init__(self, path):
+        super().__init__(self, 'Invalid data source,' +
+            ' module at "{}" does not spcify required member "Source"')
+
+class Source():
+    @classmethod
+    def from_file(cls, modulepath, jsonpath):
+        # construct a relative path
+        relpath = '.'.join([''] + modulepath)
+        # import modules relative to this package
+        module = import_module(relpath, __package__)
+        if not module.Source:
+            raise InvalidSourceModuleExeption(relpath)
+
+        return Source(jsonpath, module.Source())
+
+    def __init__(self, path, source):
+        self.path = path
+        self.source = source
+
+    def call(self, env):
+        cache = SourceCache.getinstance()
+        cache_result = cache.get(self)
+        if cache_result:
+            return cache_result
+
+        args = []
+        for argname in self.source.required_args():
+            args.append(env[argname])
+
+        result = self.source.call(*args)
+        cache.put(self, result, self.source.cache_ttl())
+
+        return result
+
+class Provider():
+    @classmethod
+    def from_directory(cls, basepath, dirname):
+        provider = Provider(dirname)
+
+        sourcepaths = find_modules(os.path.join(basepath, dirname))
+        for path in sourcepaths:
+            for fname in path[1]:
+                src = Source.from_file([dirname] + path[0] + [fname], path[0] + [fname])
+                provider.add_source(src)
+
+        return provider
+
+
+    def __init__(self, name):
+        self.name = name
+        self.sources = []
+
+    def add_source(self, source):
+        self.sources.append(source)
+
+    def call(self, env):
+        ret = {}
+
+        for source in self.sources:
+            try:
+                _set_value(ret, source.path, source.call(env))
+            except:
+                traceback.print_exc()
+
+        return ret
+
+
+def get_providers(directory):
+    providers = {}
+
+    if not os.path.isdir(directory):
+        raise FileNotFoundError("The path '{}' is not a valid directory".format(directory))
+
+    for dir in source_dirs(directory):
+        provider = Provider.from_directory(directory, dir)
+
+        providers[provider.name] = provider
+
+    return providers

providers/neighbours/batadv.py

@@ -0,0 +1,22 @@
+import providers
+from glob import glob
+
+class Source(providers.DataSource):
+    def required_args(self):
+        return ['batadv_dev']
+
+    def call(self, batadv_dev):
+        return (lambda neighbours: {
+            open("{}/address".format(path)).read().strip(): {"neighbours": {
+                neigh[0]: {"lastseen": neigh[1], "tq": neigh[2]}
+                for neigh in neighbours
+                if neigh[3] == path[len('/sys/class/net/{}/lower_'.format(batadv_dev)):]
+            }}
+            for path in
+                glob('/sys/class/net/{}/lower_*'.format(batadv_dev))
+        })([
+            (line[0], float(line[1].strip('s')), int(line[2].strip(')')), line[4].strip('[]:'))
+            for line in map(lambda l: l.replace('(', '').replace('[', '').split(),
+                open('/sys/kernel/debug/batman_adv/{}/originators'.format(batadv_dev)))
+            if line[0] == line[3]
+        ])

providers/neighbours/node_id.py

@@ -0,0 +1 @@
+../nodeinfo/node_id.py

providers/nodeinfo/hardware/nproc.py

@@ -0,0 +1,6 @@
+import providers
+import multiprocessing
+
+class Source(providers.DataSource):
+    def call(self):
+        return multiprocessing.cpu_count()

providers/nodeinfo/hostname.py

@@ -0,0 +1,6 @@
+import providers
+import socket
+
+class Source(providers.DataSource):
+    def call(self):
+        return socket.gethostname()

providers/nodeinfo/network/addresses.py

@@ -0,0 +1,26 @@
+import providers
+from ipaddress import IPv6Address
+from glob import glob
+
+class Source(providers.DataSource):
+    def required_args(self):
+        return ['batadv_dev']
+
+    def call(self, batadv_dev):
+        # filter addresses from /proc/net/if_inet6 belonging to given ifaces
+        return (lambda ifaces:
+            [
+                str(IPv6Address(int(line[0], 16)))
+                for line in map(str.split, open('/proc/net/if_inet6'))
+                if line[5] in ifaces
+                    and not int(line[4], 16) & (0x40 | 0x20)
+                    # address is neither tentative nor deprecated
+            ]
+        )(
+            # generate the list of ifaces
+            [ batadv_dev ] +
+            list(map(
+                lambda s: s[len('/sys/class/net/{}/upper_'.format(batadv_dev)):],
+                glob('/sys/class/net/{}/upper_*'.format(batadv_dev))
+            ))
+        )