diff --git a/docker/install-dependencies.sh b/docker/install-dependencies.sh
index 33ad9e9..670b75d 100755
--- a/docker/install-dependencies.sh
+++ b/docker/install-dependencies.sh
@@ -11,6 +11,12 @@ dependencies=(
     python3-flask
     python3-gunicorn
     python3-kafka
+    # kafka-python negotiates no compression of its own: it must be able to
+    # decompress whatever codec the producer chose. Without the codec library
+    # the batch raises UnsupportedCodecError from the consumer iterator, which
+    # is outside the per-message error handling in kafka_backend(), so the
+    # process exits and restarts onto the same batch forever.
+    python3-snappy
     python3-koji
     python3-qpid-proton
     python3-pip