Add prefix to redis keys

Since the GNQC application might find itself sharing the same redis
server and/or database with other applications, add a prefix to its
keys.

1 files changed, 27 insertions, 9 deletions

diff --git a/qc_app/jobs.py b/qc_app/jobs.py
index f5e5173..dc1f967 100644
--- a/qc_app/jobs.py
+++ b/qc_app/jobs.py
@@ -3,15 +3,32 @@ import os
 import sys
 import shlex
 import subprocess
-from typing import Union
 from uuid import UUID, uuid4
 from datetime import timedelta
+from typing import Union, Optional
 
 from redis import Redis
+from flask import current_app as app
+
+JOBS_PREFIX = "JOBS"
 
 class JobNotFound(Exception):
     """Raised if we try to retrieve a non-existent job."""
 
+def jobsnamespace():
+    """
+    Return the jobs namespace prefix. It depends on app configuration.
+
+    Calling this function outside of an application context will cause an
+    exception to be raised. It is mostly a convenience utility to use within the
+    application.
+    """
+    return f"{app.config['GNQC_REDIS_PREFIX']}:{JOBS_PREFIX}"
+
+def job_key(namespaceprefix: str, jobid: Union[str, UUID]) -> str:
+    """Build the key by appending it to the namespace prefix."""
+    return f"{namespaceprefix}:{jobid}"
+
 def raise_jobnotfound(jobid: Union[str,UUID]):
     """Utility to raise a `NoSuchJobError`"""
     raise JobNotFound(f"Could not retrieve job '{jobid}'.")
@@ -21,15 +38,16 @@ def error_filename(job_id, error_dir):
     return f"{error_dir}/job_{job_id}.error"
 
 def initialise_job(# pylint: disable=[too-many-arguments]
-        redis_conn: Redis, job_id: str, command: list, job_type: str,
-        ttl_seconds: int, extra_meta: dict) -> dict:
+        rconn: Redis, rprefix: str, jobid: str, command: list, job_type: str,
+        ttl_seconds: int = 86400, extra_meta: Optional[dict] = None) -> dict:
     "Initialise a job 'object' and put in on redis"
     the_job = {
-        "job_id": job_id, "command": shlex.join(command), "status": "pending",
-        "percent": 0, "job-type": job_type, **extra_meta
+        "job_id": jobid, "command": shlex.join(command), "status": "pending",
+        "percent": 0, "job-type": job_type, **(extra_meta or {})
     }
-    redis_conn.hset(name=the_job["job_id"], mapping=the_job)
-    redis_conn.expire(name=the_job["job_id"], time=timedelta(seconds=ttl_seconds))
+    rconn.hset(job_key(rprefix, jobid), mapping=the_job)
+    rconn.expire(
+        name=job_key(rprefix, jobid), time=timedelta(seconds=ttl_seconds))
     return the_job
 
 def build_file_verification_job(#pylint: disable=[too-many-arguments]
@@ -85,7 +103,7 @@ def launch_job(the_job: dict, redisurl: str, error_dir):
 
     return the_job
 
-def job(redis_conn, job_id: Union[str,UUID]):
+def job(rconn: Redis, rprefix: str, jobid: Union[str,UUID]):
     "Retrieve the job"
-    thejob = redis_conn.hgetall(str(job_id)) or raise_jobnotfound(job_id)
+    thejob = rconn.hgetall(job_key(rprefix, jobid)) or raise_jobnotfound(jobid)
     return thejob