Decentralised crawling should work in theory + temporary fix for going further than the maximum 10k results elasticsearch allows by default

app.py

@@ -8,7 +8,7 @@ from flask_recaptcha import ReCaptcha
 import od_util
 import config
 from flask_caching import Cache
-from task import TaskDispatcher, Task
+from task import TaskDispatcher, Task, CrawlServer
 from search.search import ElasticSearchEngine
 
 app = Flask(__name__)
@@ -349,8 +349,9 @@ def admin_dashboard():
 
         tokens = db.get_tokens()
         blacklist = db.get_blacklist()
+        crawl_servers = db.get_crawl_servers()
 
-        return render_template("dashboard.html", api_tokens=tokens, blacklist=blacklist)
+        return render_template("dashboard.html", api_tokens=tokens, blacklist=blacklist, crawl_servers=crawl_servers)
     else:
         return abort(403)
 
@@ -416,6 +417,37 @@ def admin_crawl_logs():
         return abort(403)
 
 
+@app.route("/crawl_server/add", methods=["POST"])
+def admin_add_crawl_server():
+    if "username" in session:
+
+        server = CrawlServer(
+            request.form.get("url"),
+            request.form.get("name"),
+            request.form.get("slots"),
+            request.form.get("token")
+        )
+
+        db.add_crawl_server(server)
+        flash("Added crawl server", "success")
+        return redirect("/dashboard")
+
+    else:
+        return abort(403)
+
+
+@app.route("/crawl_server/<int:server_id>/delete")
+def admin_delete_crawl_server(server_id):
+    if "username" in session:
+
+        db.remove_crawl_server(server_id)
+        flash("Deleted crawl server", "success")
+        return redirect("/dashboard")
+
+    else:
+        abort(403)
+
+
 if __name__ == '__main__':
     if config.USE_SSL:
         context = ssl.SSLContext(ssl.PROTOCOL_SSLv23)

crawl_server/crawler.py

@@ -84,7 +84,7 @@ class RemoteDirectoryCrawler:
         self.crawled_paths = list()
 
     def crawl_directory(self, out_file: str) -> CrawlResult:
-
+        try:
             try:
                 directory = RemoteDirectoryFactory.get_directory(self.url)
                 path, root_listing = directory.list_dir("")
@@ -124,6 +124,8 @@ class RemoteDirectoryCrawler:
             file_writer_thread.join()
 
             return CrawlResult(files_written[0], "success")
+        except Exception as e:
+            return CrawlResult(0, str(e) + " \nType:" + str(type(e)))
 
     def _process_listings(self, url: str, in_q: Queue, files_q: Queue):
 

crawl_server/server.py

@@ -7,15 +7,14 @@ import config
 app = Flask(__name__)
 auth = HTTPTokenAuth(scheme="Token")
 
-tokens = [config.CRAWL_SERVER_TOKEN]
+token = config.CRAWL_SERVER_TOKEN
 
 tm = TaskManager("tm_db.sqlite3", 32)
 
 
 @auth.verify_token
-def verify_token(token):
+def verify_token(provided_token):
-    if token in tokens:
+    return token == provided_token
-        return True
 
 
 @app.route("/task/")
@@ -99,4 +98,4 @@ def get_stats():
 
 
 if __name__ == "__main__":
-    app.run(port=5001, host="0.0.0.0")
+    app.run(port=config.CRAWL_SERVER_PORT, host="0.0.0.0", ssl_context="adhoc")

database.py

@@ -4,6 +4,7 @@ from urllib.parse import urlparse
 import os
 import bcrypt
 import uuid
+import task
 
 
 class InvalidQueryException(Exception):
@@ -277,6 +278,33 @@ class Database:
             cursor.execute("SELECT * FROM BlacklistedWebsite")
             return [BlacklistedWebsite(r[0], r[1]) for r in cursor.fetchall()]
 
+    def add_crawl_server(self, server: task.CrawlServer):
+
+        with sqlite3.connect(self.db_path) as conn:
+            cursor = conn.cursor()
+
+            cursor.execute("INSERT INTO CrawlServer (url, name, slots, token) VALUES (?,?,?,?)",
+                           (server.url, server.name, server.slots, server.token))
+            conn.commit()
+
+    def remove_crawl_server(self, server_id):
+
+        with sqlite3.connect(self.db_path) as conn:
+            cursor = conn.cursor()
+
+            cursor.execute("DELETE FROM CrawlServer WHERE id=?", (server_id, ))
+            conn.commit()
+
+    def get_crawl_servers(self) -> list:
+
+        with sqlite3.connect(self.db_path) as conn:
+            cursor = conn.cursor()
+
+            cursor.execute("SELECT url, name, slots, token, id FROM CrawlServer")
+
+            return [task.CrawlServer(r[0], r[1], r[2], r[3], r[4]) for r in cursor.fetchall()]
+
+
 
 
 

init_script.sql

@@ -23,3 +23,11 @@ CREATE TABLE BlacklistedWebsite (
   id INTEGER PRIMARY KEY NOT NULL,
   url TEXT
 );
+
+CREATE TABLE CrawlServer (
+  id INTEGER PRIMARY KEY NOT NULL,
+  url TEXT,
+  name TEXT,
+  token TEXT,
+  slots INTEGER
+)

requirements.txt

@@ -15,3 +15,4 @@ python-dateutil
 flask_httpauth
 ujson
 timeout_decorator
+urllib3

search/search.py

@@ -168,7 +168,7 @@ class ElasticSearchEngine(SearchEngine):
                     "path": {"pre_tags": ["<mark>"], "post_tags": ["</mark>"]}
                 }
             },
-            "size": per_page, "from": page * per_page}, index=self.index_name)
+            "size": per_page, "from": min(page * per_page, 10000 - per_page)}, index=self.index_name)
 
         return page
 

task.py

@@ -1,31 +1,41 @@
+import random
+
 from apscheduler.schedulers.background import BackgroundScheduler
 from search.search import ElasticSearchEngine
 from crawl_server.database import Task, TaskResult
 import requests
 from requests.exceptions import ConnectionError
 import json
-import config
+import database
-from database import Database
+from concurrent.futures import ThreadPoolExecutor
+import urllib3
+
+urllib3.disable_warnings()
 
 
 class CrawlServer:
 
-    headers = {
+    def __init__(self, url, name, slots, token, server_id=None):
-        "Content-Type": "application/json",
-        "Authorization": "Token " + config.CRAWL_SERVER_TOKEN,
-    }
-
-    def __init__(self, url, name):
         self.url = url
         self.name = name
+        self.slots = slots
+        self.used_slots = 0
+        self.token = token
+        self.id = server_id
+
+    def _generate_headers(self):
+        return {
+            "Content-Type": "application/json",
+            "Authorization": "Token " + self.token,
+        }
 
     def queue_task(self, task: Task) -> bool:
 
         print("Sending task to crawl server " + self.url)
         try:
             payload = json.dumps(task.to_json())
-            r = requests.post(self.url + "/task/put", headers=CrawlServer.headers, data=payload)
+            r = requests.post(self.url + "/task/put", headers=self._generate_headers(), data=payload, verify=False)
-            print(r)
+            print(r)  # TODO: If the task could not be added, fallback to another server
             return r.status_code == 200
         except ConnectionError:
             return False
@@ -33,40 +43,63 @@ class CrawlServer:
     def fetch_completed_tasks(self) -> list:
 
         try:
-            r = requests.get(self.url + "/task/completed", headers=CrawlServer.headers)
+            r = requests.get(self.url + "/task/completed", headers=self._generate_headers(), verify=False)
+            if r.status_code != 200:
+                print("Problem while fetching completed tasks for '" + self.name + "': " + str(r.status_code))
+                print(r.text)
+                return []
             return [
                 TaskResult(r["status_code"], r["file_count"], r["start_time"], r["end_time"], r["website_id"])
                 for r in json.loads(r.text)]
         except ConnectionError:
-            print("Crawl server cannot be reached " + self.url)
+            print("Crawl server cannot be reached @ " + self.url)
             return []
 
-    def fetch_queued_tasks(self) -> list:
+    def fetch_queued_tasks(self):
 
         try:
-            r = requests.get(self.url + "/task/", headers=CrawlServer.headers)
+            r = requests.get(self.url + "/task/", headers=self._generate_headers(), verify=False)
+
+            if r.status_code != 200:
+                print("Problem while fetching queued tasks for '" + self.name + "' " + str(r.status_code))
+                print(r.text)
+                return None
+
             return [
                 Task(t["website_id"], t["url"], t["priority"], t["callback_type"], t["callback_args"])
                 for t in json.loads(r.text)
             ]
         except ConnectionError:
-            return []
+            return None
 
     def fetch_current_tasks(self):
 
         try:
-            r = requests.get(self.url + "/task/current", headers=CrawlServer.headers)
+            r = requests.get(self.url + "/task/current", headers=self._generate_headers(), verify=False)
+
+            if r.status_code != 200:
+                print("Problem while fetching current tasks for '" + self.name + "' " + str(r.status_code))
+                print(r.text)
+                return None
+
             return [
                 Task(t["website_id"], t["url"], t["priority"], t["callback_type"], t["callback_args"])
                 for t in json.loads(r.text)
             ]
         except ConnectionError:
-            return []
+            return None
 
     def fetch_website_files(self, website_id) -> str:
 
         try:
-            r = requests.get(self.url + "/file_list/" + str(website_id) + "/", stream=True, headers=CrawlServer.headers)
+            r = requests.get(self.url + "/file_list/" + str(website_id) + "/", stream=True,
+                             headers=self._generate_headers(), verify=False)
+
+            if r.status_code != 200:
+                print("Problem while fetching website files for '" + self.name + "': " + str(r.status_code))
+                print(r.text)
+                return ""
+
             for line in r.iter_lines(chunk_size=1024 * 256):
                 yield line
         except ConnectionError:
@@ -75,7 +108,8 @@ class CrawlServer:
     def free_website_files(self, website_id) -> bool:
 
         try:
-            r = requests.get(self.url + "/file_list/" + str(website_id) + "/free", headers=CrawlServer.headers)
+            r = requests.get(self.url + "/file_list/" + str(website_id) + "/free", headers=self._generate_headers(),
+                             verify=False)
             return r.status_code == 200
         except ConnectionError as e:
             print(e)
@@ -84,16 +118,29 @@ class CrawlServer:
     def fetch_crawl_logs(self):
 
         try:
-            r = requests.get(self.url + "/task/logs/", headers=CrawlServer.headers)
+            r = requests.get(self.url + "/task/logs/", headers=self._generate_headers(), verify=False)
+
+            if r.status_code != 200:
+                print("Problem while fetching crawl logs for '" + self.name + "': " + str(r.status_code))
+                print(r.text)
+                return []
+
             return [
-                TaskResult(r["status_code"], r["file_count"], r["start_time"], r["end_time"], r["website_id"], r["indexed_time"])
+                TaskResult(r["status_code"], r["file_count"], r["start_time"],
+                           r["end_time"], r["website_id"], r["indexed_time"])
                 for r in json.loads(r.text)]
         except ConnectionError:
             return []
 
     def fetch_stats(self):
         try:
-            r = requests.get(self.url + "/stats/", headers=CrawlServer.headers)
+            r = requests.get(self.url + "/stats/", headers=self._generate_headers(), verify=False)
+
+            if r.status_code != 200:
+                print("Problem while fetching stats for '" + self.name + "': " + str(r.status_code))
+                print(r.text)
+                return []
+
             return json.loads(r.text)
         except ConnectionError:
             return {}
@@ -107,16 +154,11 @@ class TaskDispatcher:
         scheduler.start()
 
         self.search = ElasticSearchEngine("od-database")
-        self.db = Database("db.sqlite3")
+        self.db = database.Database("db.sqlite3")
-
-        # TODO load from config
-        self.crawl_servers = [
-            CrawlServer("http://localhost:5001", "OVH_VPS_SSD2 #1"),
-        ]
 
     def check_completed_tasks(self):
 
-        for server in self.crawl_servers:
+        for server in self.db.get_crawl_servers():
             for task in server.fetch_completed_tasks():
                 print("Completed task")
                 # All files are overwritten
@@ -135,24 +177,63 @@ class TaskDispatcher:
         self._get_available_crawl_server().queue_task(task)
 
     def _get_available_crawl_server(self) -> CrawlServer:
-        # TODO: Load balancing & health check for crawl servers
+
-        return self.crawl_servers[0]
+        queued_tasks_by_server = self._get_current_tasks_by_server()
+        server_with_most_free_slots = None
+        most_free_slots = 0
+
+        for server in queued_tasks_by_server:
+            free_slots = server.slots - len(queued_tasks_by_server[server])
+            if free_slots > most_free_slots:
+                server_with_most_free_slots = server
+                most_free_slots = free_slots
+
+        if server_with_most_free_slots:
+            print("Dispatching task to '" +
+                  server_with_most_free_slots.name + "' " +
+                  str(most_free_slots) + " free out of " + str(server_with_most_free_slots.slots))
+
+        return self.db.get_crawl_servers()[0]
 
     def get_queued_tasks(self) -> list:
 
-        queued_tasks = []
+        queued_tasks_by_server = self._get_current_tasks_by_server()
+        for queued_tasks in queued_tasks_by_server.values():
+            for task in queued_tasks:
+                yield task
 
-        for server in self.crawl_servers:
+    def _get_queued_tasks_by_server(self) -> dict:
-            queued_tasks.extend(server.fetch_queued_tasks())
+
+        queued_tasks = dict()
+        pool = ThreadPoolExecutor(max_workers=10)
+        crawl_servers = self.db.get_crawl_servers()
+        responses = list(pool.map(lambda server: server.fetch_queued_tasks()))
+        pool.shutdown()
+
+        for i, server in enumerate(crawl_servers):
+            if responses[i] is not None:
+                queued_tasks[server] = responses[i]
 
         return queued_tasks
 
-    def get_current_tasks(self) -> list:
+    def get_current_tasks(self):
-        # TODO mem cache this
 
-        current_tasks = []
+        current_tasks_by_server = self._get_current_tasks_by_server()
-        for server in self.crawl_servers:
+        for current_tasks in current_tasks_by_server.values():
-            current_tasks.extend(server.fetch_current_tasks())
+            for task in current_tasks:
+                yield task
+
+    def _get_current_tasks_by_server(self) -> dict:
+
+        current_tasks = dict()
+        pool = ThreadPoolExecutor(max_workers=10)
+        crawl_servers = self.db.get_crawl_servers()
+        responses = list(pool.map(lambda s: s.fetch_current_tasks(), crawl_servers))
+        pool.shutdown()
+
+        for i, server in enumerate(crawl_servers):
+            if responses[i] is not None:
+                current_tasks[server] = responses[i]
 
         return current_tasks
 
@@ -160,7 +241,7 @@ class TaskDispatcher:
 
         task_logs = dict()
 
-        for server in self.crawl_servers:
+        for server in self.db.get_crawl_servers():
             task_logs[server.name] = server.fetch_crawl_logs()
 
         return task_logs
@@ -169,11 +250,9 @@ class TaskDispatcher:
 
         stats = dict()
 
-        for server in self.crawl_servers:
+        for server in self.db.get_crawl_servers():
             server_stats = server.fetch_stats()
             if server_stats:
                 stats[server.name] = server_stats
 
         return stats
-
-

templates/dashboard.html

@@ -7,6 +7,48 @@
             <div class="card-header">Dashboard</div>
             <div class="card-body">
 
+                <h3>Crawl servers</h3>
+                <table class="table table-striped">
+                    <thead>
+                    <tr>
+                        <th>Url</th>
+                        <th>Name</th>
+                        <th>Slots</th>
+                        <th>Action</th>
+                    </tr>
+                    </thead>
+                    <tbody>
+                    {% for server in crawl_servers %}
+                        <tr>
+                            <td>{{ server.url }}</td>
+                            <td>{{ server.name }}</td>
+                            <td>{{ server.slots }}</td>
+                            <td><a class="btn btn-danger" href="/crawl_server/{{ server.id }}/delete">Delete</a></td>
+                        </tr>
+                    {% endfor %}
+                    </tbody>
+                </table>
+                <form action="/crawl_server/add" method="post">
+                    <div class="form-row">
+                        <div class="col col-md-3">
+                            <input class="form-control" name="url" placeholder="Url">
+                        </div>
+                        <div class="col col-md-3">
+                            <input class="form-control" name="name" placeholder="Name">
+                        </div>
+                        <div class="col col-md-2">
+                            <input class="form-control" name="token" placeholder="Token">
+                        </div>
+                        <div class="col col-md-2">
+                            <input class="form-control" name="slots" placeholder="Slots" type="number">
+                        </div>
+                        <div class="col col-md-2">
+                            <input type="submit" class="form-control btn btn-primary" value="Add server">
+                        </div>
+                    </div>
+                </form>
+                <br>
+                <hr>
                 <h3>API Keys</h3>
                 <table class="table table-striped">
                     <thead>