Graceful container shutdown

Use stopsignal with buildImage
Use exec so binary process is primary pid

Author: TrevorBenson

Diff for: CHANGELOG.md

@@ -1,5 +1,7 @@
 # Revision history for cardano-db-sync
 
+- Fixes an issue where stopping the docker container results in non graceful shutdown
+
 ## 13.6.0.4
 - Fixes an issue from ledger where DRep delegations could be removed under some conditions
 - Fix an issue with migration from 13.5.x when consumed_tx_out config is enabled

Diff for: nix/docker.nix

@@ -24,7 +24,10 @@ let
 
   baseImage = dockerTools.buildImage {
     name = "cardano-db-sync-base-env";
-    config.Env = [ "NIX_SSL_CERT_FILE=${cacert}/etc/ssl/certs/ca-bundle.crt" ];
+    config = {
+      Env = [ "NIX_SSL_CERT_FILE=${cacert}/etc/ssl/certs/ca-bundle.crt" ];
+      StopSignal = "SIGINT";
+    };
 
     copyToRoot = buildEnv {
       name = "base-image-env";
@@ -93,7 +96,7 @@ let
         db-sync = pkgs.writeScriptBin "cardano-db-sync-${service.cluster}" ''
           #!${runtimeShell}
           set -euo pipefail
-          ${service.script} $@
+          exec ${service.script} $@
         '' // {
           passthru = { inherit service; };
         };