scripts: Log to redis

Add a logger that will log output to a redis list. This will be useful
to retrieve the output(s) of the running script to help display some
form of progress to the user.

1 files changed, 34 insertions, 0 deletions

diff --git a/scripts/redis_logger.py b/scripts/redis_logger.py
new file mode 100644
index 0000000..c3a71db
--- /dev/null
+++ b/scripts/redis_logger.py
@@ -0,0 +1,34 @@
+"""Utilities to log to redis for our worker scripts."""
+import uuid
+import json
+import logging
+from typing import Any
+
+from redis import Redis
+
+class RedisLogger(logging.Handler):
+    """Log out to redis for our worker scripts"""
+    def __init__(self,
+                 rconn: Redis,
+                 jobid: uuid.UUID,
+                 level:int = logging.NOTSET,
+                 messagelistname: str = "log-messages",
+                 expiry: int = 86400):
+        """Initialise the handler."""
+        super().__init__(level)
+        self.redisconnection = rconn
+        self.jobid = jobid
+        self.messagelistname = messagelistname
+        self.expiry = expiry
+        rconn.hset(name=str(jobid),
+                   key="log-messagelist",
+                   value=self.messages_list_name())
+
+    def messages_list_name(self):
+        return f"{str(self.jobid)}:{self.messagelistname}"
+
+    def emit(self, record):
+        """Log to the messages list for a given worker."""
+        self.redisconnection.rpush(
+            self.messages_list_name(), self.format(record))
+        self.redisconnection.expire(self.messages_list_name(), self.expiry)