generate systemd: refactor

Refactor the systemd-unit generation code and move all the logic into
`pkg/systemd/generate`.  The code was already hard to maintain but I
found it impossible to wire the `--new` logic for pods in all the chaos.

The code refactoring in this commit will make maintaining the code
easier and should make it easier to extend as well.  Further changes and
refactorings may still be needed but they will easier.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

1 files changed, 36 insertions, 0 deletions

diff --git a/pkg/systemd/generate/common.go b/pkg/systemd/generate/common.go
new file mode 100644
index 000000000..e809b4837
--- /dev/null
+++ b/pkg/systemd/generate/common.go
@@ -0,0 +1,36 @@
+package generate
+
+import (
+	"github.com/pkg/errors"
+)
+
+// EnvVariable "PODMAN_SYSTEMD_UNIT" is set in all generated systemd units and
+// is set to the unit's (unique) name.
+const EnvVariable = "PODMAN_SYSTEMD_UNIT"
+
+// restartPolicies includes all valid restart policies to be used in a unit
+// file.
+var restartPolicies = []string{"no", "on-success", "on-failure", "on-abnormal", "on-watchdog", "on-abort", "always"}
+
+// validateRestartPolicy checks that the user-provided policy is valid.
+func validateRestartPolicy(restart string) error {
+	for _, i := range restartPolicies {
+		if i == restart {
+			return nil
+		}
+	}
+	return errors.Errorf("%s is not a valid restart policy", restart)
+}
+
+const headerTemplate = `# {{.ServiceName}}.service
+# autogenerated by Podman {{.PodmanVersion}}
+{{- if .TimeStamp}}
+# {{.TimeStamp}}
+{{- end}}
+
+[Unit]
+Description=Podman {{.ServiceName}}.service
+Documentation=man:podman-generate-systemd(1)
+Wants=network.target
+After=network-online.target
+`