Developer Containers Part 2#

The developer container you built in the previous tutorial is a complete EPICS environment. This short follow-up shows two things you can do with it once your IOC is running: talk to the IOC with the EPICS command-line tools inside the container, and launch Phoebus on the host to view the IOC’s auto-generated engineering screens.

Note

If you closed the container after the last tutorial, reopen it and restart the IOC:

cd ioc-adsimdetector
code .            # then ctrl-shift-p -> "Reopen in Container"

# only if the container was rebuilt do you need to rebuild the IOC:
ibek dev instance /workspaces/t01-services/services/bl01t-ea-cam-01
cd /epics/ioc && make

# otherwise just start it:
/epics/ioc/start.sh

Channel Access#

The container ships the full set of EPICS tools, so caget, caput and camonitor work against the running IOC from any VSCode terminal. The IOC shell is still occupying the terminal you started it in, so open a second terminal (Terminal → New Terminal) for these commands and leave the IOC running:

caget BL01T-EA-CAM-01:DET:Acquire
caput BL01T-EA-CAM-01:DET:Acquire 1
caput BL01T-EA-CAM-01:ARR:EnableCallbacks 1
# read the first 10 elements of the (changing) image array
caget -#10 BL01T-EA-CAM-01:ARR:ArrayData

Warning

Channel Access sees the IOC’s PVs both via localhost and UDP broadcast so you will get a warning like:

Warning: "Identical process variable names on multiple servers"

To silence this warning, make CA look only at localhost before running caget/caput:

export EPICS_CA_ADDR_LIST=localhost EPICS_CA_AUTO_ADDR_LIST=NO

You are root inside the container (podman maps that back to your own user on the host), so no sudo is needed. The image is Ubuntu-based, so install any extra tool you need with apt update && apt install <package>.

Phoebus#

Generic IOCs use PVI to auto-generate Phoebus engineering screens — one for the driver and one for every AreaDetector plugin in the instance. The IOC’s opi/ folder ships a launcher script that opens them.

Important

Run the launcher on the host, not inside the developer container. It looks for a host Phoebus install or starts a Phoebus container, neither of which works from within the dev container.

# run this OUTSIDE the developer container
cd ioc-adsimdetector
./opi/phoebus-launch.sh

By default the script launches Phoebus in a container (ghcr.io/epics-containers/ec-phoebus:latest). To use a local install instead, comment out the use_container=1 line at the top of opi/phoebus-launch.sh; it then runs phoebus.sh from your PATH. Either way the script fills in the correct Channel Access and PV Access ports for you, so Phoebus connects straight to the IOC running in the container.

Phoebus opens opi/auto-generated/index.bob, the entry point to the generated screens. The opi/auto-generated/ folder is not committed to git — the IOC fills it in at runtime. You should see a button for the simDetector driver and for each plugin; click through to interact with the detector.

Note

For how a client outside the container reaches an IOC running inside it, see EPICS Network Protocols in Containers.

A nicer overview screen#

Earlier we used a hand-coded screen with a proper image widget that worked with the same IOC instance we are using now (see Run It and View the Screens). To open it, close Phoebus and relaunch it pointing at that screen:

./opi/phoebus-launch.sh -resource /workspaces/t01-services/opi/demo-simdet.bob
../_images/custom_bob.png

A hand-coded overview screen for bl01t-ea-cam-01.#