switch to --mount syntax for bind mounts

Author: hjwp

chapter_09_docker.asciidoc

@@ -1340,8 +1340,9 @@ CMD python manage.py runserver
 ----
 ====
 
-The extra flag to add is `-v`, and it takes a similar `outside:inside` argument as `-p` did for ports.
-We specify a folder or file _outside_ the container, and the path we want it to appear at _inside_ the container.
+The extra flag to add is `--mount`,
+where we specify `type=bind`, the `source` path on our machine,
+and the `target` path _inside_ the container:
 
 [role="small-code"]
 [subs="specialcharacters,quotes"]
@@ -1355,23 +1356,16 @@ Running migrations:
   Applying sessions.0001_initial... OK
 $ *docker build -t superlists . && docker run \
   -p 8888:8888 \
-  -v ./src/db.sqlite3:/src/db.sqlite3 \
+  --mount type=bind,source=./src/db.sqlite3,target=/src/db.sqlite3 \ 
   -it superlists*
 ----
 
-////
-footgun: if you don't have db.sqlite3
-
-docker: Error response from daemon: error while creating mount source path '/Users/harry.percival/workspace/Book-TDD-Web-Dev-Python/source/chapter_09_docker/superlists/src/db.sqlite3': chown /Users/harry.percival/workspace/Book-TDD-Web-Dev-Python/source/chapter_09_docker/superlists/src/db.sqlite3: permission denied.
-ERRO[0000] error waiting for container: context canceled
-
-❯ ls src/db.sqlite3/
-////
-
+TIP: The old syntax for mounts was `-v`.
+    One of the advantages of the new `--mount` syntax is that it will fail hard
+    if the path you're trying to mount into the container does not exist
+    (it says something like `bind source path does not exist`)
+    This avoids a lot of pain, ask me how I now this.
 
-TIP: if you see an error saying: `django.db.utils.OperationalError`: "unable to open database file",
-    try stopping the container, `rm -rf src/db.sqlite3`, then re-run the migrate command
-    _outside_ the container, and then rebuild and run your image.
 
 
 And we check the FTs again.

chapter_10_production_readiness.asciidoc

@@ -91,7 +91,7 @@ pattern to try out our changes by rebuilding and rerunning our container:
 ----
 $ *docker build -t superlists . && docker run \
   -p 8888:8888 \
-  -v ./src/db.sqlite3:/src/db.sqlite3 \
+  --mount type=bind,source=./src/db.sqlite3,target=/src/db.sqlite3 \ 
   -it superlists*
 ----
 
@@ -290,7 +290,7 @@ And try it out...
 ----
 $ pass:specialcharacters,quotes[*docker build -t superlists . && docker run \
   -p 8888:8888 \
-  -v ./src/db.sqlite3:/src/db.sqlite3 \
+  --mount type=bind,source=./src/db.sqlite3,target=/src/db.sqlite3 \ 
   -it superlists*]
 
 [...]
@@ -316,7 +316,7 @@ For now, we can set it at the command line using the `-e` flag for `docker run`:
 ----
 $ *docker build -t superlists . && docker run \
   -p 8888:8888 \
-  -v ./src/db.sqlite3:/src/db.sqlite3 \
+  --mount type=bind,source=./src/db.sqlite3,target=/src/db.sqlite3 \ 
   -e DJANGO_SECRET_KEY=sekrit \
   -it superlists*
 ----
@@ -400,11 +400,11 @@ or on a server, so we'll use the `-e` flag again:
 [subs="specialcharacters,quotes"]
 ----
 $ *docker build -t superlists . && docker run \
-      -p 8888:8888 \
-      -v ./src/db.sqlite3:/src/db.sqlite3 \
-      -e DJANGO_SECRET_KEY=sekrit \
-      -e DJANGO_ALLOWED_HOST=localhost \
-      -it superlists*
+    -p 8888:8888 \
+    --mount type=bind,source=./src/db.sqlite3,target=/src/db.sqlite3 \ 
+    -e DJANGO_SECRET_KEY=sekrit \
+    -e DJANGO_ALLOWED_HOST=localhost \
+    -it superlists*
 ----