From f8a273ecd03bfb0bd10ee27d1a833feb47ea4634 Mon Sep 17 00:00:00 2001
From: Brandon Keepers <brandon@opensoul.org>
Date: Wed, 25 Feb 2026 10:08:03 -0500
Subject: [PATCH] Add congen to the Docker image

---
 Dockerfile | 16 ++++++++++++----
 README.md  | 10 +++++++++-
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index 4c39bec..4320249 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,7 @@
 ARG LIBTCD_VERSION=2.2.7-r3
 ARG XTIDE_VERSION=2.16
 ARG TCD_UTILS_VERSION=20240222
+ARG CONGEN_VERSION=1.7-r2
 ARG HARMONICS_VERSION=20251228
 
 # ---------------------------------------------------------------------------
@@ -11,6 +12,7 @@ FROM debian:bookworm-slim AS builder
 ARG LIBTCD_VERSION
 ARG XTIDE_VERSION
 ARG TCD_UTILS_VERSION
+ARG CONGEN_VERSION
 ARG HARMONICS_VERSION
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
@@ -35,6 +37,12 @@ RUN curl -fsSL "https://flaterco.com/files/xtide/tcd-utils-${TCD_UTILS_VERSION}.
   && cd tcd-utils-*/ \
   && ./configure && make && make install
 
+# congen (tarball dir strips release suffix, e.g. 1.7-r2 -> congen-1.7)
+RUN curl -fsSL "https://flaterco.com/files/xtide/congen-${CONGEN_VERSION}.tar.xz" | tar xJ \
+  && cd congen-*/ \
+  && ./configure && make && make install \
+  && curl -fsSL -o /usr/local/share/congen_input.txt "https://flaterco.com/files/xtide/congen_input.txt"
+
 # harmonics data (tarball dir omits -free suffix)
 RUN mkdir -p /usr/local/share/xtide \
   && curl -fsSL "https://flaterco.com/files/xtide/harmonics-dwf-${HARMONICS_VERSION}-free.tar.xz" | tar xJ \
@@ -46,10 +54,10 @@ RUN mkdir -p /usr/local/share/xtide \
 FROM debian:bookworm-slim
 
 LABEL org.opencontainers.image.title="XTide" \
-      org.opencontainers.image.description="Tide prediction software with CLI (tide), web server (xttpd), and tcd-utils" \
-      org.opencontainers.image.url="https://github.com/openwatersio/xtide-docker" \
-      org.opencontainers.image.source="https://github.com/openwatersio/xtide-docker" \
-      org.opencontainers.image.licenses="GPL-3.0-or-later"
+  org.opencontainers.image.description="Tide prediction software with CLI (tide), web server (xttpd), tcd-utils, and congen" \
+  org.opencontainers.image.url="https://github.com/openwatersio/xtide-docker" \
+  org.opencontainers.image.source="https://github.com/openwatersio/xtide-docker" \
+  org.opencontainers.image.licenses="GPL-3.0-or-later"
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
   libpng16-16 zlib1g \
diff --git a/README.md b/README.md
index 7c8d65f..7bf8584 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # xtide Docker image
 
-Docker image for [XTide](https://flaterco.com/xtide/), a tide prediction program. Includes the `tide` CLI, `xttpd` web server, and `tcd-utils` (`build_tide_db`, `restore_tide_db`), compiled from source with harmonics data.
+Docker image for [XTide](https://flaterco.com/xtide/), a tide prediction program. Includes the `tide` CLI, `xttpd` web server, `tcd-utils` (`build_tide_db`, `restore_tide_db`), and `congen` (tidal constituent generator), compiled from source with harmonics data.
 
 ## Usage
 
@@ -31,6 +31,14 @@ docker run --rm ghcr.io/openwatersio/xtide restore_tide_db -h
 docker run --rm ghcr.io/openwatersio/xtide build_tide_db -h
 ```
 
+### congen
+
+Generate speeds, equilibrium arguments, and node factors for tidal constituents. The default input file is included at `/usr/local/share/congen_input.txt`.
+
+```sh
+docker run --rm ghcr.io/openwatersio/xtide congen < /usr/local/share/congen_input.txt
+```
+
 ## Custom Harmonics File
 
 The image includes the free harmonics dataset from [flaterco.com](https://flaterco.com/xtide/files.html). To use a custom `.tcd` harmonics file, mount it into the container and set the `HFILE_PATH` environment variable: