diff --git a/.dockerignore b/.dockerignore
index 93f136199..16bf40211 100644
--- a/.dockerignore
+++ b/.dockerignore
@@ -1,2 +1,26 @@
-node_modules
-npm-debug.log
+**
+
+# .git directories required for generating version.txt
+
+!/.git/
+!/docs/
+!/files/
+!/test/files/
+
+!/client/.browserslistrc
+!/client/.git/
+!/client/package.json
+!/client/package-lock.json
+!/client/vue.config.js
+!/client/public/
+!/client/src/
+
+!/server/.npmrc
+!/server/.git/
+!/server/package.json
+!/server/package-lock.json
+!/server/Makefile
+!/server/pm2.config.js
+!/server/config/
+!/server/docs/
+!/server/lib/
diff --git a/.github/workflows/test-docker-context.yml b/.github/workflows/test-docker-context.yml
new file mode 100644
index 000000000..f917740a9
--- /dev/null
+++ b/.github/workflows/test-docker-context.yml
@@ -0,0 +1,19 @@
+name: Test docker context
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  build:
+    timeout-minutes: 3
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        fetch-depth: 0
+        fetch-tags: true
+        submodules: recursive
+    # Some reasonable boundaries; these may change in future.  Numbers outside
+    # these bounds indicate a misconfiguration, and should be investigated.
+    - run: ./test/check-docker-context.sh --min-size 30000 --max-size 50000 --min-count 500 --max-count 1000