git init

.gitignore

+## Build
+/build/
+/ccache/
+
+## Snapshot Artifacts
+/*.git/
+/*.tar*
+/*.version
+
+## Editors
+*~
+.*.sw[op]

get_snapshot

+#!/bin/bash
+# Copyright (c) 2017 Icinga Development Team <info@icinga.com>
+# Licensed as GPL-2.0+
+
+set -e
+
+while getopts ":p:U:b:" opt
+do
+    case "$opt" in
+    p)
+        PROJECT="$OPTARG"
+        ;;
+    U)
+        UPSTREAM_GIT_URL="$OPTARG"
+        ;;
+    b)
+        UPSTREAM_GIT_BRANCH="$OPTARG"
+        ;;
+    \?)
+        echo "Unknown argument: $OPTARG" >&2
+        exit 1
+        ;;
+    esac
+done
+
+: "${PROJECT:=icingabuildtest}"
+: "${UPSTREAM_GIT_URL:=https://github.com/Icinga/$PROJECT.git}"
+: "${UPSTREAM_GIT_BRANCH:=master}"
+
+workdir="$(pwd)"
+
+set -x
+
+if [ -z "$UPSTREAM_GIT_NOREPO" ]; then
+    if [ -d "${PROJECT}.git/" ]; then
+        cd "${PROJECT}.git"
+        if [ ! -d .git ]; then
+            echo "This is not a GIT repository: $(pwd)" >&2
+            exit 1
+        fi
+        if [ -z "$UPSTREAM_GIT_NOUPDATE" ]; then
+            if [ "$(git config remote.origin.url)" != "${UPSTREAM_GIT_URL}" ]; then
+                git remote set-url origin "${UPSTREAM_GIT_URL}"
+            fi
+            git fetch origin -p
+            git checkout -f "${UPSTREAM_GIT_BRANCH}"
+            git reset --hard "origin/${UPSTREAM_GIT_BRANCH}"
+        fi
+        git clean -fdx
+    elif [ -z "$UPSTREAM_GIT_NOUPDATE" ]; then
+        git clone -b "${UPSTREAM_GIT_BRANCH}" "${UPSTREAM_GIT_URL}" "${PROJECT}.git/"
+        cd "${PROJECT}.git"
+    else
+        echo "Missing '${PROJECT}.git' directory!" >&2
+        exit 1
+    fi
+fi
+
+git_version=$(git describe --long --tags "${UPSTREAM_GIT_BRANCH}")
+package_version=$(echo "$git_version" | sed -e 's/^v//' -e 's/-/./g')
+tarball="${workdir}/${PROJECT}-${package_version}.tar.gz"
+
+git archive --format=tar --prefix="${PROJECT}-${package_version}/" -o "${tarball}" "${UPSTREAM_GIT_BRANCH}"
+
+sha256sum "${tarball}"
+
+# store package version for build scripts
+echo -e "${package_version}\t$(git rev-parse "${UPSTREAM_GIT_BRANCH}")\t$(basename "${tarball}")\t${UPSTREAM_GIT_BRANCH}" > "${workdir}/${PROJECT}.version"

icingabuildtest.spec

+Summary:        Icinga Build test package
+License:        GPLv2+
+Group:          System/Monitoring
+Name:           icingabuildtest
+Version:        1.0.0
+Release:        1%{?dist}
+Url:            https://www.icinga.com
+Source:         https://github.com/Icinga/%{name}/archive/v%{version}.tar.gz
+
+BuildArch:      noarch
+BuildRoot:      %{_tmppath}/%{name}-%{version}-build
+
+Requires:       bash
+
+%description
+This is just a test package.
+
+%prep
+%setup -q -n %{name}-%{version}
+
+%build
+bash icingabuildtest
+
+%install
+install -d %{buildroot}%{_bindir}
+install -m 0755 icingabuildtest %{buildroot}%{_bindir}/icingabuildtest
+
+%files
+%defattr(-,root,root,-)
+%{_bindir}/icingabuildtest
+
+%changelog
+* Thu Feb 07 2019 Markus Frosch <markus.frosch@icinga.com> 1.0.0-1
+- Initial package