Add Makefile targets and README for easier PDB debugging.

Makefile

@@ -82,12 +82,18 @@ restore:  ## Restore all data volumes from the host. WARNING: THIS WILL OVERWRIT
 credentials-shell: ## Run a shell on the credentials container
 	docker exec -it edx.devstack.credentials env TERM=$(TERM) bash
 
+credentials-attach: ## Attach to the credentials container process to use the debugger & see logs.
+	docker attach `docker ps -aqf "name=edx.devstack.credentials"`
+
 e2e-shell: ## Start the end-to-end tests container with a shell
 	docker run -it --network=devstack_default -v ${DEVSTACK_WORKSPACE}/edx-e2e-tests:/edx-e2e-tests -v ${DEVSTACK_WORKSPACE}/edx-platform:/edx-e2e-tests/lib/edx-platform --env-file ${DEVSTACK_WORKSPACE}/edx-e2e-tests/devstack_env edxops/e2e env TERM=$(TERM) bash
 
 lms-shell: ## Run a shell on the LMS container
 	docker exec -it edx.devstack.lms env TERM=$(TERM) /edx/app/edxapp/devstack.sh open
 
+lms-attach: ## Attach to the LMS container process to use the debugger & see logs.
+	docker attach `docker ps -aqf "name=edx.devstack.lms"`
+
 studio-shell: ## Run a shell on the Studio container
 	docker exec -it edx.devstack.studio env TERM=$(TERM) /edx/app/edxapp/devstack.sh open
 
@@ -105,6 +111,9 @@ studio-static: ## Rebuild static assets for the Studio container
 
 static: | credentials-static discovery-static ecommerce-static lms-static studio-static ## Rebuild static assets for all service containers
 
+studio-attach: ## Attach to the Studio container process to use the debugger & see logs.
+	docker attach `docker ps -aqf "name=edx.devstack.cms"`
+
 healthchecks: ## Run a curl against all services' healthcheck endpoints to make sure they are up. This will eventually be parameterized
 	./healthchecks.sh
 
@@ -137,4 +146,3 @@ build-courses: ## NOTE: marketing course creation is not available for those out
 
 check-memory:
 	@if [ `docker info --format '{{json .}}' | python -c "from __future__ import print_function; import sys, json; print(json.load(sys.stdin)['MemTotal'])"` -lt 2147483648 ]; then echo "\033[0;31mWarning, System Memory is set too low!!! Increase Docker memory to be at least 2 Gigs\033[0m"; fi || exit 0
-	
\ No newline at end of file

README.rst

@@ -389,6 +389,42 @@ PyCharm Integration
 
 See the `Pycharm Integration documentation`_.
 
+Debugging using PDB
+-------------------
+
+It's possible to debug any of the containers' Python services using PDB. To do so,
+start up the containers as usual with:
+
+.. code:: sh
+
+    make dev.up
+
+This command starts each relevant container with the equivalent of the '--it' option,
+allowing a developer to attach to the process once the process is up and running.
+
+To attach to the LMS/Studio containers and their process, use either:
+
+.. code:: sh
+
+    make lms-attach
+    make studio-attach
+
+Set a PDB breakpoint anywhere in the code using:
+
+.. code:: sh
+
+    import pdb;pdb.set_trace()
+
+and your attached session will offer an interactive PDB prompt when the breakpoint is hit.
+
+To detach from the container, you'll need to stop the container with:
+
+.. code:: sh
+
+    make stop
+
+or a manual Docker command to bring down the container.
+
 Running LMS and Studio Tests
 ----------------------------
 

docker-compose.yml

@@ -80,6 +80,9 @@ services:
     depends_on:
       - mysql
       - memcached
+    # Allows attachment to the credentials service using 'docker attach <containerID>'.
+    stdin_open: true
+    tty: true
     environment:
       CACHE_LOCATION: edx.devstack.memcached:12211
       DB_HOST: edx.devstack.mysql
@@ -96,6 +99,9 @@ services:
       - mysql
       - elasticsearch
       - memcached
+    # Allows attachment to the discovery service using 'docker attach <containerID>'.
+    stdin_open: true
+    tty: true
     environment:
       TEST_ELASTICSEARCH_URL: "http://edx.devstack.elasticsearch:9200"
       ENABLE_DJANGO_TOOLBAR: 1
@@ -109,6 +115,9 @@ services:
     depends_on:
       - mysql
       - memcached
+    # Allows attachment to the ecommerce service using 'docker attach <containerID>'.
+    stdin_open: true
+    tty: true
     environment:
       ENABLE_DJANGO_TOOLBAR: 1
     image: edxops/ecommerce:devstack
@@ -122,6 +131,9 @@ services:
       - mysql
       - memcached
       - mongo
+    # Allows attachment to the LMS service using 'docker attach <containerID>'.
+    stdin_open: true
+    tty: true
     environment:
       BOK_CHOY_HOSTNAME: edx.devstack.lms
       BOK_CHOY_LMS_PORT: 18003
@@ -145,6 +157,9 @@ services:
       - mysql
       - memcached
       - mongo
+    # Allows attachment to the Studio service using 'docker attach <containerID>'.
+    stdin_open: true
+    tty: true
     environment:
       BOK_CHOY_HOSTNAME: edx.devstack.studio
       BOK_CHOY_LMS_PORT: 18103