allow synapse to use redis unix socket instead of tcp

roles/custom/matrix-synapse/defaults/main.yml

@@ -1241,11 +1241,16 @@ matrix_synapse_instance_map: |
 
 # Redis information
 matrix_synapse_redis_enabled: false
-matrix_synapse_redis_host: ""
-matrix_synapse_redis_port: 6379
 matrix_synapse_redis_password: ""
 matrix_synapse_redis_dbid: 0
 matrix_synapse_redis_use_tls: false
+# Connection option 1: TCP
+matrix_synapse_redis_host: ""
+matrix_synapse_redis_port: 6379
+# Connection option 2: Unix socket (takes precedence over TCP if `matrix_synapse_redis_path` is set)
+matrix_synapse_redis_path_enabled: false
+matrix_synapse_redis_path: "" # the path to the redis socket inside the container, e.g. "/var/run/redis.sock"
+matrix_synapse_redis_path_host: "" # the path to the redis socket on the host, e.g. "/matrix/valkey/run/valkey.sock"
 
 # Controls whether Synapse starts a replication listener necessary for workers.
 #

roles/custom/matrix-synapse/templates/synapse/homeserver.yaml.j2

@@ -2932,6 +2932,11 @@ redis:
   host: {{ matrix_synapse_redis_host | to_json }}
   port: {{ matrix_synapse_redis_port | to_json }}
 
+  # The full path to a local Unix socket file. If this is used, host and port are ignored.
+  {% if matrix_synapse_redis_path_enabled %}
+  path: {{ matrix_synapse_redis_path | to_json }}
+  {% endif %}
+
   # Optional database ID to connect to. Defaults to 0.
   dbid: {{ matrix_synapse_redis_dbid | to_json }}
 

roles/custom/matrix-synapse/templates/synapse/systemd/matrix-synapse-worker.service.j2

@@ -67,6 +67,9 @@ ExecStartPre={{ devture_systemd_docker_base_host_command_docker }} create \
 			{% for volume in matrix_synapse_container_additional_volumes %}
 			--mount type={{ volume.type | default('bind' if '/' in volume.src else 'volume') }},src={{ volume.src }},dst={{ volume.dst }}{{ (',' + volume.options) if volume.options else '' }} \
 			{% endfor %}
+			{% if matrix_synapse_redis_path_enabled %}
+			--mount type=bind,src={{ matrix_synapse_redis_path_host }},dst={{ matrix_synapse_redis_path }} \
+			{% endif %}
 			--label-file={{ matrix_synapse_base_path }}/{{ matrix_synapse_worker_labels_file_name }} \
 			{% for arg in matrix_synapse_container_arguments %}
 			{{ arg }} \

roles/custom/matrix-synapse/templates/synapse/systemd/matrix-synapse.service.j2

@@ -51,6 +51,9 @@ ExecStartPre={{ devture_systemd_docker_base_host_command_docker }} create \
 			{% endif %}
 			--mount type=bind,src={{ matrix_synapse_config_dir_path }},dst=/data,ro \
 			--mount type=bind,src={{ matrix_synapse_storage_path }},dst=/matrix-media-store-parent,bind-propagation=slave \
+			{% if matrix_synapse_redis_path_enabled %}
+			--mount type=bind,src={{ matrix_synapse_redis_path_host }},dst={{ matrix_synapse_redis_path }} \
+			{% endif %}
 			--label-file={{ matrix_synapse_base_path }}/labels \
 			{% for volume in matrix_synapse_container_additional_volumes %}
 			--mount type={{ volume.type | default('bind' if '/' in volume.src else 'volume') }},src={{ volume.src }},dst={{ volume.dst }}{{ (',' + volume.options) if volume.options else '' }} \