add scraper

scraper/management/commands/scrape.py

@@ -0,0 +1,137 @@
+"""
+This script starts at a seed instance and loads the list of connected
+peers. From there, it slowly scrapes the peers of all instances it finds,
+gradually mapping the fediverse.
+"""
+import json
+import multiprocessing
+import requests
+from django.core.management.base import BaseCommand
+from scraper.models import Instance, InstanceStats
+
+# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
+# Because the script uses the Mastodon API other platforms like         #
+# Pleroma, Peertube, Pixelfed, Funkwhale won't have outgoing peers.     #
+#                                                                       #
+# The script generates two files:                                       #
+# - nodes.csv                                                           #
+# - edges.csv                                                           #
+#                                                                       #
+# Change SEED to start from a different instance.                       #
+# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
+
+SEED = 'mastodon.social'
+THREADS = 100
+TIMEOUT = 10
+
+
+class InvalidResponseError(Exception):
+    """Used for all responses other than HTTP 200"""
+    pass
+
+
+def get_key(data, keys: list):
+    try:
+        val = data[keys.pop(0)]
+        while keys:
+            val = val[keys.pop(0)]
+        return val
+    except KeyError:
+        return ''
+
+
+def get_instance_info(instance_name: str):
+    """Collect info about instance"""
+    url = 'https://' + instance_name + '/api/v1/instance'
+    response = requests.get(url, timeout=TIMEOUT)
+    if response.status_code != 200:
+        raise InvalidResponseError("Could not get info for {}".format(instance_name))
+    return response.json()
+
+
+def get_instance_peers(instance_name: str):
+    """Collect connected instances"""
+    url = 'https://' + instance_name + '/api/v1/instance/peers'
+    response = requests.get(url, timeout=TIMEOUT)
+    if response.status_code != 200:
+        raise InvalidResponseError("Could not get peers for {}".format(instance_name))
+    return response.json()
+
+
+def process_instance(instance_name: str):
+    """Given an instance, get all the data we're interested in"""
+    print("Processing {}".format(instance_name))
+    data = dict()
+    try:
+        data['instance'] = instance_name
+        data['info'] = get_instance_info(instance_name)
+        data['peers'] = get_instance_peers(instance_name)
+        data['status'] = 'success'
+        print("Processed: {}".format(instance_name))
+        return data
+    except (InvalidResponseError,
+            requests.exceptions.RequestException,
+            json.decoder.JSONDecodeError) as e:
+        data['instance'] = instance_name
+        data['status'] = type(e).__name__
+        print("Failed: {}".format(instance_name))
+        return data
+
+
+def save_data(data):
+    """Save data"""
+    instance, _ = Instance.objects.get_or_create(name=get_key(data, ['instance']))
+    if data['status'] == 'success':
+        # Save stats
+        stats = InstanceStats(
+            instance=instance,
+            num_peers=get_key(data, ['info', 'stats', 'domain_count']),
+            num_statuses=get_key(data, ['info', 'stats', 'status_count']),
+            num_users=get_key(data, ['info', 'stats', 'user_count']),
+            version=get_key(data, ['info', 'version']),
+            status=get_key(data, ['status']),
+        )
+        stats.save()
+        # Save peers
+        # TODO: optimization opportunity here if we do this in bulk
+        # Make sure to consider race conditions
+        # https://stackoverflow.com/q/24502658/3697202
+        peers = [Instance.objects.get_or_create(name=n) for n in data['peers']]
+        instance.peers.add(*[peers])
+    else:
+        stats = InstanceStats(
+            instance=instance,
+            status=get_key(data, ['status'])
+        )
+        stats.save()
+
+
+def worker(queue: multiprocessing.JoinableQueue, done_bag: set):
+    """The main worker that processes URLs"""
+    while True:
+        # Get an item from the queue. Block if the queue is empty.
+        instance = queue.get()
+        if instance in done_bag:
+            print("Skipping {}, already done".format(instance))
+            queue.task_done()
+        else:
+            data = process_instance(instance)
+            if 'peers' in data:
+                for peer in [p for p in data['peers'] if p not in done_bag]:
+                    queue.put(peer)
+            save_data(data)
+            done_bag.add(instance)
+            queue.task_done()
+
+
+class Command(BaseCommand):
+    help = "Scrapes the entire fediverse"
+
+
+    def handle(self, *args, **options):
+        done_bag = set()
+        queue = multiprocessing.JoinableQueue()
+        queue.put(SEED)
+        pool = multiprocessing.Pool(THREADS, initializer=worker, initargs=(queue, done_bag))
+        queue.join()
+        self.stdout.write(self.style.SUCCESS("Successfully scraped the fediverse"))

scraper/migrations/0002_auto_20180826_0053.py

@@ -0,0 +1,42 @@
+# Generated by Django 2.1 on 2018-08-26 00:53
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('scraper', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='instance',
+            name='id',
+        ),
+        migrations.AlterField(
+            model_name='instance',
+            name='name',
+            field=models.CharField(max_length=200, primary_key=True, serialize=False),
+        ),
+        migrations.AlterField(
+            model_name='instancestats',
+            name='num_peers',
+            field=models.IntegerField(blank=True),
+        ),
+        migrations.AlterField(
+            model_name='instancestats',
+            name='num_statuses',
+            field=models.IntegerField(blank=True),
+        ),
+        migrations.AlterField(
+            model_name='instancestats',
+            name='num_users',
+            field=models.IntegerField(blank=True),
+        ),
+        migrations.AlterField(
+            model_name='instancestats',
+            name='version',
+            field=models.CharField(blank=True, max_length=1000),
+        ),
+    ]

scraper/migrations/0003_auto_20180826_0057.py

@@ -0,0 +1,28 @@
+# Generated by Django 2.1 on 2018-08-26 00:57
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('scraper', '0002_auto_20180826_0053'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='instancestats',
+            name='num_peers',
+            field=models.IntegerField(blank=True, null=True),
+        ),
+        migrations.AlterField(
+            model_name='instancestats',
+            name='num_statuses',
+            field=models.IntegerField(blank=True, null=True),
+        ),
+        migrations.AlterField(
+            model_name='instancestats',
+            name='num_users',
+            field=models.IntegerField(blank=True, null=True),
+        ),
+    ]

scraper/migrations/0004_auto_20180826_0100.py

@@ -0,0 +1,18 @@
+# Generated by Django 2.1 on 2018-08-26 01:00
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('scraper', '0003_auto_20180826_0057'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='instance',
+            name='peers',
+            field=models.ManyToManyField(to='scraper.Instance'),
+        ),
+    ]

scraper/models.py

@@ -2,18 +2,18 @@ from django.db import models
 
 
 class Instance(models.Model):
-    name = models.CharField(max_length=200)
-    peers = models.ManyToManyField('self', related_name='followers', symmetrical=False)
+    name = models.CharField(max_length=200, primary_key=True)
+    peers = models.ManyToManyField('self', symmetrical=False)
 
 
 class InstanceStats(models.Model):
     timestamp = models.DateTimeField(auto_now_add=True)
     instance = models.ForeignKey(
-        'Instance',
+        Instance,
         on_delete=models.CASCADE,
     )
-    num_peers = models.IntegerField()
-    num_statuses = models.IntegerField()
-    num_users = models.IntegerField()
-    version = models.CharField(max_length=1000)
+    num_peers = models.IntegerField(blank=True, null=True)
+    num_statuses = models.IntegerField(blank=True, null=True)
+    num_users = models.IntegerField(blank=True, null=True)
+    version = models.CharField(max_length=1000, blank=True)
     status = models.CharField(max_length=100)