deploy: make the build context overridable for Compose Manager

deploy/.env.example

@@ -6,3 +6,8 @@ REFRAIN_IPV4=REPLACE-with-a-free-lan-ip
 # Host path for the memory root — a git repo of markdown, the only
 # irreplaceable data in this stack. Back it up.
 REFRAIN_DATA=REPLACE-with-a-host-path
+
+# Only needed when this compose file has been copied away from the repo,
+# so the default `context: ..` no longer points at the repo root — see
+# "Unraid / Compose Manager" in README.md. Leave unset otherwise.
+#REFRAIN_SRC=/path/to/refrain/checkout

deploy/README.md

@@ -21,7 +21,24 @@ The reference compose file assumes a pre-existing macvlan network named
 IP. If that isn't your pattern, replace the `networks` block with a
 bridge network and publish port 8092.
 
-On Unraid, add these labels to the service for a WebUI link and shell:
+## Unraid / Compose Manager
+
+Compose Manager does not run the stack from a checkout — it requires the
+compose file to live in its own `projects/<name>/docker-compose.yml`. The
+default `context: ..` then resolves to the projects directory instead of
+the repo root, and `docker compose up -d` fails to build with no obvious
+clue why. Point `REFRAIN_SRC` at the checkout so the build context stays
+correct wherever the compose file was pasted:
+
+```
+REFRAIN_SRC=/mnt/user/appdata/refrain/src
+```
+
+The checkout has to be reachable from the Docker host, so keep it on a
+share rather than inside the compose project directory (Unraid's flash
+device is FAT-formatted and a poor place for source).
+
+Add these labels to the service for a WebUI link and shell:
 
 ```yaml
     labels:

deploy/docker-compose.yaml

@@ -19,7 +19,12 @@
 services:
   refrain:
     build:
-      context: ..
+      # Defaults to the repo root, so `docker compose up -d --build` from
+      # this directory just works. Override REFRAIN_SRC when the compose
+      # file is copied somewhere else and `..` no longer means the repo —
+      # notably Unraid's Compose Manager, which requires the file to live
+      # in its own projects/<name>/ directory (see README).
+      context: ${REFRAIN_SRC:-..}
       dockerfile: deploy/Dockerfile
     container_name: refrain
     restart: unless-stopped