[Docker] adding OAI LTE RU target build in a container image

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

docker/scripts/lte_ru_entrypoint.sh

@@ -0,0 +1,62 @@
+#!/bin/bash
+
+set -euo pipefail
+
+PREFIX=/opt/oai-lte-ru
+
+# Based another env var, pick one template to use
+if [[ -v USE_FDD_RRU ]]; then ln -s $PREFIX/etc/rru.fdd.conf $PREFIX/etc/rru.conf; fi
+if [[ -v USE_TDD_RRU ]]; then ln -s $PREFIX/etc/rru.tdd.conf $PREFIX/etc/rru.conf; fi
+
+# Only this template will be manipulated
+CONFIG_FILES=`ls $PREFIX/etc/rru.conf || true`
+
+for c in ${CONFIG_FILES}; do
+    # grep variable names (format: ${VAR}) from template to be rendered
+    VARS=$(grep -oP '@[a-zA-Z0-9_]+@' ${c} | sort | uniq | xargs)
+
+    # create sed expressions for substituting each occurrence of ${VAR}
+    # with the value of the environment variable "VAR"
+    EXPRESSIONS=""
+    for v in ${VARS}; do
+        NEW_VAR=`echo $v | sed -e "s#@##g"`
+        if [[ "${!NEW_VAR}x" == "x" ]]; then
+            echo "Error: Environment variable '${NEW_VAR}' is not set." \
+                "Config file '$(basename $c)' requires all of $VARS."
+            exit 1
+        fi
+        EXPRESSIONS="${EXPRESSIONS};s|${v}|${!NEW_VAR}|g"
+    done
+    EXPRESSIONS="${EXPRESSIONS#';'}"
+
+    # render template and inline replace config file
+    sed -i "${EXPRESSIONS}" ${c}
+done
+
+# Load the USRP binaries
+if [[ -v USE_B2XX ]]; then
+    /usr/lib/uhd/utils/uhd_images_downloader.py -t b2xx
+elif [[ -v USE_X3XX ]]; then
+    /usr/lib/uhd/utils/uhd_images_downloader.py -t x3xx
+elif [[ -v USE_N3XX ]]; then
+    /usr/lib/uhd/utils/uhd_images_downloader.py -t n3xx
+fi
+
+echo "=================================="
+echo "== Starting eNB soft modem"
+if [[ -v USE_ADDITIONAL_OPTIONS ]]; then
+    echo "Additional option(s): ${USE_ADDITIONAL_OPTIONS}"
+    new_args=()
+    while [[ $# -gt 0 ]]; do
+        new_args+=("$1")
+        shift
+    done
+    for word in ${USE_ADDITIONAL_OPTIONS}; do
+        new_args+=("$word")
+    done
+    echo "${new_args[@]}"
+    exec "${new_args[@]}"
+else
+    echo "$@"
+    exec "$@"
+fi