Add healthcheck for docker image

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add tooltips to short links on repository overview ([#1441](https://github.com/scm-manager/scm-manager/pull/1441))
 - Show the date of the last commit for branches in the frontend ([#1439](https://github.com/scm-manager/scm-manager/pull/1439))
 - Unify and add description to key view across user settings ([#1440](https://github.com/scm-manager/scm-manager/pull/1440))
+- Healthcheck for docker image ([#1428](https://github.com/scm-manager/scm-manager/issues/1428) and [#1454](https://github.com/scm-manager/scm-manager/issues/1454))
 
 ### Changed
 - Send mercurial hook callbacks over separate tcp socket instead of http ([#1416](https://github.com/scm-manager/scm-manager/pull/1416))

scm-packaging/docker/Dockerfile

@@ -41,4 +41,9 @@ VOLUME ["${SCM_HOME}", "${CACHE_DIR}"]
 EXPOSE 8080
 USER scm
 
+# we us a high relative high start period,
+# because the start time depends on the number of installed plugins
+HEALTHCHECK --interval=30s --timeout=3s --start-period=30s --retries=3 \
+  CMD wget --no-verbose --tries=1 --spider http://localhost:8080/scm/api/v2 || exit 1
+
 ENTRYPOINT [ "/opt/scm-server/bin/scm-server" ]