From 132c67d414067a29509aefe7066cd7e84656b644 Mon Sep 17 00:00:00 2001
From: Antonin Hildebrand <antonin@hildebrand.cz>
Date: Wed, 21 Mar 2018 19:09:29 +0100
Subject: [PATCH] docker: replace bash shells with last command

It is better to replace bash shell with potentially long-running
last script command. This way the running command will receive all
potential unix process signals directly.

A concrete example which motivated this change:
Exec of btcd is needed for graceful shutdown of btcd during
`docker-compose down`. Docker Compose properly sends this signal to our
start-btcd.sh bash shell but it is not further signalled to the running
btcd process. Docker Compose then kills whole container forcefully after
some timeout.

An alternative solution would be to trap SIGTERM in our bash script and
forward it to running btcd. Which would be IMO ugly and error prone.
---
 docker/btcd/start-btcctl.sh | 2 +-
 docker/btcd/start-btcd.sh   | 2 +-
 docker/lnd/start-lnd.sh     | 2 +-
 docker/ltcd/start-ltcctl.sh | 2 +-
 docker/ltcd/start-ltcd.sh   | 2 +-
 5 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/docker/btcd/start-btcctl.sh b/docker/btcd/start-btcctl.sh
index 419f73d5..e693d49d 100755
--- a/docker/btcd/start-btcctl.sh
+++ b/docker/btcd/start-btcctl.sh
@@ -43,7 +43,7 @@ RPCUSER=$(set_default "$RPCUSER" "devuser")
 RPCPASS=$(set_default "$RPCPASS" "devpass")
 NETWORK=$(set_default "$NETWORK" "simnet")
 
-btcctl \
+exec btcctl \
     "--$NETWORK" \
     --rpccert="/rpc/rpc.cert" \
     --rpcuser="$RPCUSER" \
diff --git a/docker/btcd/start-btcd.sh b/docker/btcd/start-btcd.sh
index 5f7992a0..732b5a62 100755
--- a/docker/btcd/start-btcd.sh
+++ b/docker/btcd/start-btcd.sh
@@ -67,5 +67,5 @@ PARAMS="$PARAMS $@"
 
 # Print command and start bitcoin node.
 echo "Command: btcd $PARAMS"
-btcd $PARAMS
+exec btcd $PARAMS
 
diff --git a/docker/lnd/start-lnd.sh b/docker/lnd/start-lnd.sh
index 560e3149..ed1b2462 100755
--- a/docker/lnd/start-lnd.sh
+++ b/docker/lnd/start-lnd.sh
@@ -49,7 +49,7 @@ if [[ "$CHAIN" == "litecoin" ]]; then
     BACKEND="ltcd"
 fi
 
-lnd \
+exec lnd \
     --noencryptwallet \
     --logdir="/data" \
     "--$CHAIN.active" \
diff --git a/docker/ltcd/start-ltcctl.sh b/docker/ltcd/start-ltcctl.sh
index beb12bd9..ec82ea4c 100755
--- a/docker/ltcd/start-ltcctl.sh
+++ b/docker/ltcd/start-ltcctl.sh
@@ -43,7 +43,7 @@ RPCUSER=$(set_default "$RPCUSER" "devuser")
 RPCPASS=$(set_default "$RPCPASS" "devpass")
 NETWORK=$(set_default "$NETWORK" "simnet")
 
-ltcctl \
+exec ltcctl \
     "--$NETWORK" \
     --rpccert="/rpc/rpc.cert" \
     --rpcuser="$RPCUSER" \
diff --git a/docker/ltcd/start-ltcd.sh b/docker/ltcd/start-ltcd.sh
index defac5a4..9bdbe6d0 100755
--- a/docker/ltcd/start-ltcd.sh
+++ b/docker/ltcd/start-ltcd.sh
@@ -67,5 +67,5 @@ PARAMS="$PARAMS $@"
 
 # Print command and start bitcoin node.
 echo "Command: ltcd $PARAMS"
-ltcd $PARAMS
+exec ltcd $PARAMS