Volumes instead of bind mounts (+ DKIM-key generation)

.env.example

@@ -41,16 +41,15 @@ EMAIL_SERVERS_WITH_PRIORITY=[(10, "$SUBDOMAIN.$EMAIL_DOMAIN.")]
 ## In self-hosted, you typically trust all users. Set this variable to disable this option.
 DISABLE_ALIAS_SUFFIX=1
 
-## the DKIM private key used to compute DKIM-Signature
-DKIM_PRIVATE_KEY_PATH=/dkim.key
+## DKIM_PRIVATE_KEY_PATH, GNUPGHOME, TEMP_DIR and SAVE_UNSENT_DIR are all
+## paths *inside* the container's sldata volume. There's no reason for you
+## to configure these - they're fixed in simple-login-compose.yaml.
 
 ## DB Connection
 DB_URI=postgresql://$POSTGRES_USER:$POSTGRES_PASSWORD@sl-db:5432/$POSTGRES_DB
 
 FLASK_SECRET=paste-flask-secret-here
 
-GNUPGHOME=/sl/pgp
-
 LOCAL_FILE_UPLOAD=1
 
 POSTFIX_SERVER=postfix

docker-compose.yaml

@@ -7,6 +7,10 @@ include:
   - traefik-compose.yaml
   - simple-login-compose.yaml
   - postfix-compose.yaml
+  ## Migrates pre-existing ./db, ./pgp, ./upload, ./dkim.key content (if any)
+  ## into the named volumes above. Safe to leave in for a fresh install too.
+  ## Comment out once you've confirmed the migration succeeded.
+  - migrate-volumes-compose.yaml
 
 networks:
   internal:

migrate-volumes-compose.yaml

@@ -0,0 +1,59 @@
+# One-time migration helper: copies pre-existing data from the old
+# bind-mount layout (./db, ./pgp, ./upload, ./dkim.key) into the named
+# volumes now used by simple-login-compose.yaml, if you're upgrading an
+# existing deployment.
+#
+# Safe to leave included even without any of the above present (e.g. a
+# fresh install) - it just creates the sldata directory structure and
+# does nothing else. Comment out the include line for this file in
+# docker-compose.yaml once you've confirmed the migration succeeded.
+#
+# The whole project directory is bind-mounted read-only (rather than each
+# legacy path individually) because the project directory always exists,
+# whereas e.g. ./dkim.key commonly does not on a fresh setup - bind
+# mounting a single nonexistent file path would make Docker silently
+# create an empty directory there instead of leaving it absent.
+services:
+  volume-migrate:
+    image: alpine:3.22
+    volumes:
+      - .:/legacy:ro
+      - db:/new/db
+      - sldata:/new/sldata
+      - upload:/new/upload
+    entrypoint:
+      - /bin/sh
+      - -c
+      - |
+        set -eu
+        migrate() {
+          if [ -n "$$(ls -A "$2" 2>/dev/null)" ]; then
+            echo "[volume-migrate] $2 already has data, skipping"
+            return
+          fi
+          if [ -d "$1" ] && [ -n "$$(ls -A "$1" 2>/dev/null)" ]; then
+            echo "[volume-migrate] copying existing $1 -> $2"
+            cp -a "$1"/. "$2"/
+          else
+            echo "[volume-migrate] no existing data at $1, starting fresh"
+          fi
+        }
+        mkdir -p /new/sldata/pgp /new/sldata/dkim /new/sldata/tmp /new/sldata/unsent
+        migrate /legacy/db /new/db
+        migrate /legacy/pgp /new/sldata/pgp
+        migrate /legacy/upload /new/upload
+        chmod 700 /new/sldata/pgp
+        if [ -n "$$(ls -A /new/sldata/dkim 2>/dev/null)" ]; then
+          echo "[volume-migrate] /new/sldata/dkim already has data, skipping"
+        elif [ -f /legacy/dkim.key ]; then
+          echo "[volume-migrate] copying existing dkim.key"
+          cp -a /legacy/dkim.key /new/sldata/dkim/dkim.key
+          chmod 600 /new/sldata/dkim/dkim.key
+        else
+          echo "[volume-migrate] no existing dkim.key"
+        fi
+
+  postgres:
+    depends_on:
+      volume-migrate:
+        condition: service_completed_successfully

postfix-compose.yaml

@@ -13,13 +13,36 @@ services:
     networks:
       internal:
         ipv4_address: 10.0.0.53
-    volumes:
-      - ./unbound/conf.d/:/config/:ro
     restart: unless-stopped
+    # Listener config is written at container start instead of bind-mounted
+    # from ./unbound/conf.d/, so this has no host-file dependency at all.
+    # Picked up via the image's own `include: /config/*.conf`, additively
+    # alongside its default listener on 5053 - so the image's built-in
+    # healthcheck (which probes 5053) is unaffected.
+    # Recipe: https://github.com/springcomp/self-hosted-simplelogin/pull/46#issuecomment-3707216659
+    #
+    # module-config/identity/root-hints match what the previous
+    # bind-mounted unbound/conf.d/00-unbound.conf set, to not weaken
+    # anything the upstream maintainer deliberately configured:
+    # - module-config trims the cachedb module the image loads by default
+    #   (unused without a configured cache backend)
+    # - root-hints pins the image's own dns-root-hints package file, which
+    #   the image refreshes monthly via its own cron
+    #   (/etc/periodic/monthly/dns-root-hints) - the compiled-in fallback
+    #   Unbound would otherwise use only updates when the image itself does
     entrypoint:
       - /bin/sh
       - -ec
       - |
+        cat > /config/00-listen-port.conf <<'EOF'
+        server:
+          interface: 0.0.0.0@53
+          log-queries: yes
+          verbosity: 2
+          module-config: "validator iterator"
+          identity: "DNS"
+          root-hints: "/usr/share/dns-root-hints/named.root"
+        EOF
         unbound-anchor -a /var/run/unbound/root.key || true
         exec su -s /bin/sh unbound -c "sh /entrypoint.sh"
 

simple-login-compose.yaml

@@ -1,10 +1,18 @@
 x-sl-defaults: &sl-defaults
   image: simplelogin/$SL_IMAGE:$SL_VERSION
   env_file: .env
+  # Paths inside the container - not meant to be end-user configurable
+  # (we control the whole image/volume layout), so these are fixed here
+  # rather than left for .env to set. Overrides any stale value a .env
+  # might still carry from before this change.
+  environment:
+    DKIM_PRIVATE_KEY_PATH: /sl/dkim/dkim.key
+    GNUPGHOME: /sl/pgp
+    TEMP_DIR: /sl/tmp
+    SAVE_UNSENT_DIR: /sl/unsent
   volumes:
-    - ./pgp:/sl/pgp
-    - ./upload:/code/static/upload
-    - ./dkim.key:/dkim.key
+    - sldata:/sl
+    - upload:/code/static/upload
   networks:
     - internal
 
@@ -28,7 +36,7 @@ services:
     networks:
       - internal
     volumes:
-      - ./db:/var/lib/postgresql/data
+      - db:/var/lib/postgresql/data
     restart: unless-stopped
 
   migration:
@@ -41,15 +49,51 @@ services:
 
   init:
     <<: *sl-defaults
-    command: ["python", "init_app.py"]
     container_name: sl-init
+    # Ensures the sldata volume has the directory structure the app needs,
+    # and generates a DKIM key if none exists yet - runs on every start,
+    # but only ever acts once (mkdir -p and the missing-key check are both
+    # no-ops after the first successful run). This also covers the case
+    # where migrate-volumes-compose.yaml (which does the same mkdir -p, to
+    # have somewhere to copy pre-existing bind-mounted data into) has been
+    # commented out after migration, or was never used at all.
+    entrypoint:
+      - /bin/sh
+      - -c
+      - |
+        set -eu
+        umask 077
+        mkdir -p /sl/pgp /sl/dkim /sl/tmp /sl/unsent
+        if [ ! -s "$$DKIM_PRIVATE_KEY_PATH" ]; then
+          echo "[dkim-init] No key at $$DKIM_PRIVATE_KEY_PATH — generating 1024-bit RSA key..."
+          openssl genrsa -out "$$DKIM_PRIVATE_KEY_PATH" 1024
+        fi
+        chmod 600 "$$DKIM_PRIVATE_KEY_PATH" 2>/dev/null || true
+        exec python init_app.py
     depends_on:
       migration:
         condition: service_completed_successfully
 
   app:
     <<: *sl-defaults
     container_name: sl-app
+    # Prints the DKIM public key on every start, for convenience when
+    # setting up the DNS TXT record. No set -eu here: by the time this
+    # container starts, `init` above has already guaranteed a valid key
+    # exists, and the openssl pipe below wouldn't propagate a failure from
+    # its first stage anyway (no pipefail in /bin/sh), so -e would only
+    # look like protection without actually providing any.
+    #
+    # --timeout 45 (not the Dockerfile default of 15): a fix from an
+    # earlier deployment that never made it back into the app repo.
+    entrypoint:
+      - /bin/sh
+      - -c
+      - |
+        PUB="$(openssl rsa -in "$$DKIM_PRIVATE_KEY_PATH" -pubout -outform DER 2>/dev/null | openssl base64 -A)"
+        echo "[dkim-init] DKIM public key (p=) — add this to your DNS TXT record:"
+        echo "v=DKIM1; k=rsa; p=$$PUB"
+        exec gunicorn wsgi:app -b 0.0.0.0:7777 -w 2 --timeout 45
     networks:
       - traefik
       - internal
@@ -110,3 +154,8 @@ services:
         condition: service_completed_successfully
       email:
         condition: service_started
+
+volumes:
+  db:
+  sldata:
+  upload: