Command builders for Redis Pub/Sub introspection and publishing.
This module provides pure functions that return Redis command lists for publishing messages and inspecting Pub/Sub state. These commands can be issued over a regular connection (unlike SUBSCRIBE/PSUBSCRIBE which require a dedicated Pub/Sub connection).
All functions return a command list (e.g. ["PUBLISH", "chan", "msg"]) and
are intended for use with Redis.command/2 or Redis.pipeline/2.
Examples
# Publish a message to a channel
Redis.command(conn, PubSub.publish("events", "user_signed_up"))
# List active channels matching a pattern
Redis.command(conn, PubSub.pubsub_channels(pattern: "events:*"))
# Get subscriber counts for specific channels
Redis.command(conn, PubSub.pubsub_numsub(["events:login", "events:logout"]))
# Publish to a shard channel (Redis 7+)
Redis.command(conn, PubSub.spublish("orders:{us-east}", "new_order"))Summary
Functions
PUBLISH -- post a message to a channel.
PUBSUB CHANNELS -- list active channels, optionally filtered by a glob pattern.
PUBSUB NUMSUB -- get the subscriber count for the given channels.
SPUBLISH -- post a message to a shard channel (Redis 7+).
Functions
PUBLISH -- post a message to a channel.
Returns the number of clients that received the message.
PubSub.publish("notifications", "hello")
#=> ["PUBLISH", "notifications", "hello"]PUBSUB CHANNELS -- list active channels, optionally filtered by a glob pattern.
PubSub.pubsub_channels() #=> ["PUBSUB", "CHANNELS"]
PubSub.pubsub_channels(pattern: "events:*") #=> ["PUBSUB", "CHANNELS", "events:*"]@spec pubsub_numpat() :: [String.t()]
PUBSUB NUMSUB -- get the subscriber count for the given channels.
Returns a flat list of channel/count pairs.
PubSub.pubsub_numsub(["ch1", "ch2"])
#=> ["PUBSUB", "NUMSUB", "ch1", "ch2"]SPUBLISH -- post a message to a shard channel (Redis 7+).
Similar to publish/2 but targets shard channels, which are routed only
to the cluster node owning the shard.
PubSub.spublish("orders:{us-east}", "new_order")
#=> ["SPUBLISH", "orders:{us-east}", "new_order"]