Add CPU and memory limits for apps

Adds --memory and --cpu flags to set systemd resource limits:
  ship --binary ./app --memory 512M --cpu 100%

Also adds config update mode - use --name without --binary to
update an existing app's config without redeploying the binary:
  ship --name myapp --cpu 50%
  ship --name myapp --memory 256M --env DEBUG=true

Limits are stored in state and preserved on redeploy.

2 files changed, 13 insertions, 5 deletions

diff --git a/internal/state/state.go b/internal/state/state.go
index c6de34a..38657cb 100644
--- a/internal/state/state.go
+++ b/internal/state/state.go
@@ -22,12 +22,14 @@ type Host struct {
 
 // App represents a deployed application or static site
 type App struct {
-        Type   string            `json:"type"`           // "app" or "static"
+        Type   string            `json:"type"`             // "app" or "static"
         Domain string            `json:"domain"`
-        Port   int               `json:"port,omitempty"` // only for type="app"
-        Env    map[string]string `json:"env,omitempty"`  // only for type="app"
-        Args   string            `json:"args,omitempty"` // only for type="app"
-        Files  []string          `json:"files,omitempty"` // only for type="app"
+        Port   int               `json:"port,omitempty"`   // only for type="app"
+        Env    map[string]string `json:"env,omitempty"`    // only for type="app"
+        Args   string            `json:"args,omitempty"`   // only for type="app"
+        Files  []string          `json:"files,omitempty"`  // only for type="app"
+        Memory string            `json:"memory,omitempty"` // only for type="app"
+        CPU    string            `json:"cpu,omitempty"`    // only for type="app"
 }
 
 const (
diff --git a/internal/templates/templates.go b/internal/templates/templates.go
index feb6c10..ce1cbe5 100644
--- a/internal/templates/templates.go
+++ b/internal/templates/templates.go
@@ -19,6 +19,12 @@ Restart=always
 RestartSec=5s
 NoNewPrivileges=true
 PrivateTmp=true
+{{- if .Memory}}
+MemoryMax={{.Memory}}
+{{- end}}
+{{- if .CPU}}
+CPUQuota={{.CPU}}
+{{- end}}
 
 [Install]
 WantedBy=multi-user.target