Add image parameters to compose.yaml (#1092)

Compose files can be parameterized using Bash-style (*sigh*) syntax
([1]). We add variables `JANUS_AGGREGATOR_IMAGE`,
`JANUS_MIGRATOR_IMAGE`, `DIVVIUP_API_IMAGE` and
`DIVVIUP_API_MIGRATOR_IMAGE` to allow setting Docker image tags like so:

```sh
DIVVIUP_API_IMAGE=myrepository.dev/divviup_api:0.0.1 \
  JANUS_AGGREGATOR_IMAGE=myrepository.dev/janus_aggregator:0.7.8 \
  docker compose up
```

These variables are interpolated into the `image` field of the `service`
elements ([2]). 

We also add `compose.dev.yaml`, which includes the base
`compose.yaml` and adds overrides which remove the `image`
element from the `divviup-api` services and add a `build` instead. This
causes `docker compose` to build those images from local sources, on
demand.

We provide defaults for all these images that pull from Divvi Up owned
public artifact repositories. It's somewhat unfortunate that we use a
`divviup-api` version that is behind `main`, but on the other hand the
objective is to enable a demo experience, so it makes sense to pin
Janus and divviup-api versions where the demo is known to work
end-to-end.

[1]: https://docs.docker.com/compose/compose-file/12-interpolation/
[2]: https://docs.docker.com/compose/compose-file/05-services/#image
[3]: https://docs.docker.com/compose/compose-file/build/#using-build-and-image

README.md

@@ -42,11 +42,33 @@ This will get you up and running quickly for development purposes.
 
 1. Clone the repository and navigate to its root.
 1. Execute `echo "http://localhost:8080" >app/public/api_url`
-1. Execute `docker compose watch`.
+1. Execute `docker compose up`.
 1. Navigate in your browser to `http://localhost:8081/`.
 
-`docker compose` will automatically reload containers when you make changes. Data is persisted
-until you `docker compose rm --volumes`.
+Data is persisted until you `docker compose rm --volumes`.
+
+If you want to use image versions besides the defaults, you can use environment variables
+`JANUS_AGGREGATOR_IMAGE`, `JANUS_MIGRATOR_IMAGE`, `DIVVIUP_API_IMAGE` and
+`DIVVIUP_API_MIGRATOR_IMAGE` when invoking `docker compose`.  For example:
+
+```bash
+DIVVIUP_API_IMAGE=divviup_api:localversion \
+  JANUS_IMAGE=us-west2-docker.pkg.dev/divviup-artifacts-public/janus/janus_aggregator:0.7.18 \
+  docker compose up
+```
+
+`divviup_api:localversion` will be pulled from the local Docker repository and
+`us-west2-docker.pkg.dev/divviup-artifacts-public/janus/janus_aggregator:0.7.18` will be pulled from
+`us-west2-docker.pkg.dev`.
+
+We also provide `compose.dev.yaml`, which will build `divviup-api` from local sources. Try:
+
+```bash
+docker compose -f compose.dev.yaml watch
+```
+
+`docker compose` will automatically reload containers when you make changes. The `JANUS_IMAGE` and
+`JANUS_MIGRATOR_IMAGE` variables are honored by `compose.dev.yaml`.
 
 Two Janus aggregators will be created for you, but are not automatically paired to divviup-api.
 Their information is:
@@ -58,6 +80,7 @@ testing client, they are mapped to `localhost:9001` and `localhost:9002`, respec
 
 If using the divviup CLI, consider compiling with the `--features admin` option. Also, set these
 environment variables.
+
 ```bash
 # This token is intentionally blank, but you'll still need to set the variable.
 export DIVVIUP_TOKEN=

compose.dev.override.yaml

@@ -0,0 +1,31 @@
+# Overrides for the local development docker compose setup. Meant only to be used by
+# compose.dev.yaml
+
+services:
+  divviup_api:
+    image: !reset null
+    build:
+      context: .
+      args:
+        RUST_PROFILE: dev
+        RUST_FEATURES: integration-testing
+    develop:
+      watch:
+        - path: src/
+          action: rebuild
+
+  divviup_api_migrate:
+    image: !reset null
+    build:
+      context: .
+      args:
+        RUST_PROFILE: dev
+        # This isn't strictly required for migrations, but it allows reusing one container image
+        # for both this and the divviup_api service.
+        RUST_FEATURES: integration-testing
+    develop:
+      watch:
+        - path: migration
+          action: rebuild
+          ignore:
+            - README.md

compose.dev.yaml

@@ -0,0 +1,8 @@
+# Local development-only compose file which builds divviup-api from source. This is not suitable for
+# production!
+
+include:
+  - path:
+    # These files are ordered deliberately so that they will be merged correctly
+    - compose.yaml
+    - compose.dev.override.yaml

compose.yaml

@@ -1,7 +1,7 @@
-# Local development-only compose file. This is not suitable for production!
+# Compose file for bringing up a simple local Divvi Up environment. This is not suitable for production!
 
 x-janus-common: &janus_common
-  image: us-west2-docker.pkg.dev/divviup-artifacts-public/janus/janus_aggregator:0.7.7
+  image: ${JANUS_AGGREGATOR_IMAGE:-us-west2-docker.pkg.dev/divviup-artifacts-public/janus/janus_aggregator:0.7.7}
   restart: always
   healthcheck:
     test: ["CMD", "/bin/sh", "-c", "wget http://0.0.0.0:8000/healthz -O - >/dev/null"]
@@ -12,7 +12,7 @@ x-janus-common: &janus_common
       condition: service_completed_successfully
 
 x-janus-migrate: &janus_migrate
-  image: us-west2-docker.pkg.dev/divviup-artifacts-public/janus/janus_db_migrator:0.7.7
+  image: ${JANUS_MIGRATOR_IMAGE:-us-west2-docker.pkg.dev/divviup-artifacts-public/janus/janus_db_migrator:0.7.7}
   command:
     - migrate
     - run
@@ -43,13 +43,7 @@ services:
         target: /docker-entrypoint-initdb.d/postgres_init.sql
 
   divviup_api_migrate:
-    build:
-      context: .
-      args:
-        RUST_PROFILE: dev
-        # This isn't strictly required for migrations, but it allows reusing one container image
-        # for both this and the divviup_api service.
-        RUST_FEATURES: integration-testing
+    image: ${DIVVIUP_API_MIGRATOR_IMAGE:-us-west2-docker.pkg.dev/divviup-artifacts-public/divviup-api/divviup_api:0.3.12}
     entrypoint:
       - /migration
       - up
@@ -58,19 +52,9 @@ services:
     depends_on:
       postgres:
         condition: service_started
-    develop:
-      watch:
-        - path: migration
-          action: rebuild
-          ignore:
-            - README.md
 
   divviup_api:
-    build:
-      context: .
-      args:
-        RUST_PROFILE: dev
-        RUST_FEATURES: integration-testing
+    image: ${DIVVIUP_API_IMAGE:-us-west2-docker.pkg.dev/divviup-artifacts-public/divviup-api/divviup_api:0.3.12}
     ports:
       - "8080:8080"
     environment:
@@ -89,10 +73,6 @@ services:
     depends_on:
       divviup_api_migrate:
         condition: service_completed_successfully
-    develop:
-      watch:
-        - path: src/
-          action: rebuild
 
   divviup_api_vite:
     build: