simple web log viewing for admins

app/main.py

@@ -6,6 +6,7 @@ from wand import image
 from app.models import Account, AccountInvitation, CharacterInfo
 from app.schemas import AccountSchema, CharacterInfoSchema
 from app.luclient import query_cdclient
+from app import gm_level
 
 main_blueprint = Blueprint('main', __name__)
 
@@ -40,3 +41,37 @@ def favicon():
         'favicon.ico',
         mimetype='image/vnd.microsoft.icon'
     )
+
+@main_blueprint.route('/logs')
+@gm_level(9)
+def logs():
+    with open('nexus_dashboard.log', 'r') as file:
+        logs = tail(file, 100)
+    return render_template('main/logs.html.j2', logs=logs)
+
+def tail( f, lines=20 ):
+    total_lines_wanted = lines
+
+    BLOCK_SIZE = 1024
+    f.seek(0, 2)
+    block_end_byte = f.tell()
+    lines_to_go = total_lines_wanted
+    block_number = -1
+    blocks = [] # blocks of size BLOCK_SIZE, in reverse order starting
+                # from the end of the file
+    while lines_to_go > 0 and block_end_byte > 0:
+        if (block_end_byte - BLOCK_SIZE > 0):
+            # read the last block we haven't yet read
+            f.seek(block_number*BLOCK_SIZE, 2)
+            blocks.append(f.read(BLOCK_SIZE))
+        else:
+            # file too small, start from begining
+            f.seek(0,0)
+            # only read what was not read
+            blocks.append(f.read(block_end_byte))
+        lines_found = blocks[-1].count('\n')
+        lines_to_go -= lines_found
+        block_end_byte -= BLOCK_SIZE
+        block_number -= 1
+    all_read_text = ''.join(reversed(blocks))
+    return '</br>'.join(all_read_text.splitlines()[-total_lines_wanted:])

app/templates/main/logs.html.j2

@@ -0,0 +1,13 @@
+{% extends 'base.html.j2' %}
+
+{% block title %}LOGS{% endblock %}
+
+{% block content_before %}
+ LOGS - {{ config.APP_NAME }}
+{% endblock %}
+
+{% block content_override %}
+  <code>
+    {{ logs }}
+  </code>
+{% endblock %}