client: container: support CLI with entrypoint addition (#4126)

This will allow running netbird commands (including debugging) against the daemon and provide a flow similar to non-container usages.

It will by default both log to file and stderr so it can be handled more uniformly in container-native environments.

client/Dockerfile

@@ -1,9 +1,27 @@
-FROM alpine:3.21.3
+# build & run locally with:
+#   cd "$(git rev-parse --show-toplevel)"
+#   CGO_ENABLED=0 go build -o netbird ./client
+#   sudo podman build -t localhost/netbird:latest -f client/Dockerfile --ignorefile .dockerignore-client .
+#   sudo podman run --rm -it --cap-add={BPF,NET_ADMIN,NET_RAW} localhost/netbird:latest
+
+FROM alpine:3.22.0
 # iproute2: busybox doesn't display ip rules properly
-RUN apk add --no-cache ca-certificates ip6tables iproute2 iptables
+RUN apk add --no-cache \
+    bash \
+    ca-certificates \
+    ip6tables \
+    iproute2 \
+    iptables
+
+ENV \
+    NETBIRD_BIN="/usr/local/bin/netbird" \
+    NB_LOG_FILE="console,/var/log/netbird/client.log" \
+    NB_DAEMON_ADDR="unix:///var/run/netbird.sock" \
+    NB_ENTRYPOINT_SERVICE_TIMEOUT="5" \
+    NB_ENTRYPOINT_LOGIN_TIMEOUT="1"
+
+ENTRYPOINT [ "/usr/local/bin/netbird-entrypoint.sh" ]
 
 ARG NETBIRD_BINARY=netbird
-COPY ${NETBIRD_BINARY} /usr/local/bin/netbird
-
-ENV NB_FOREGROUND_MODE=true
-ENTRYPOINT [ "/usr/local/bin/netbird","up"]
+COPY client/netbird-entrypoint.sh /usr/local/bin/netbird-entrypoint.sh
+COPY "${NETBIRD_BINARY}"  /usr/local/bin/netbird