Implement async. comm. with Python interpreter

Creating, destroying and communicationg with the interpreter subprocess
is now handled by a thread attached to PythonSession. Interpreter is
sandboxed using libseccomp.

1 files changed, 30 insertions, 10 deletions

diff --git a/readme.md b/readme.md
index a7e11ca..61b0ac6 100644
--- a/readme.md
+++ b/readme.md
@@ -1,6 +1,19 @@
 Deployment
 ==========
 
+Install the following packages:
+
+  - apache2
+  - python3 (>= 3.4)
+  - python3-ply
+  - python3-psycopg2
+  - python3-termcolor
+  - swi-prolog-nox (>= 7.2)
+  - nodejs (>= 10.0.22)
+
+SWI prolog
+----------
+
 To use the correct SWI prolog package (>= 7.2) on Debian, add a custom
 repository by creating the file /etc/apt/sources.list.d/prolog.list
 containing the following 2 lines:
@@ -16,17 +29,23 @@ apt-get update
 apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys EF8406856DBFCA18
 apt-get update
 
-Install the following packages:
+libseccomp
+----------
 
-  - apache2
-  - python3 (>= 3.4)
-  - python3-ply
-  - python3-psycopg2
-  - python3-termcolor
-  - swi-prolog-nox (>= 7.2)
-  - nodejs (>= 10.0.22)
+A new version of libseccomp (≥ 2.2) with Python bindings is needed to sandbox
+Python interpreters. This is not available yet in most distributions, so fetch
+the latest sources with
+
+    git clone https://github.com/seccomp/libseccomp
+
+then build and install it with
+
+    ./configure --enable-python
+    make
+    make install
 
-Settings:
+Settings
+--------
 
   - point webroot to codeq-web
   - set up reverse proxy for /ws/ to the node server:
@@ -43,7 +62,8 @@ Settings:
   - run "npm install" inside the "web" directory to install all dependencies
     (they will be installed inside the "web" directory)
 
-Running:
+Running
+-------
 
   - run the prolog interpreter server: swipl prolog/runner/main.pl
   - run the python interpreter server: python3 python/runner/main.py