Add --update option to deploy create

To allow updating an existing deployment

- Check the deployment dir exists when updating
- Write to temp dir, then safely copy tree
- Don't overwrite data dir or config.env

docs/cli.md

@@ -65,3 +65,71 @@ Force full rebuild of packages:
 ```
 $ laconic-so build-npms --include <package-name> --force-rebuild
 ```
+
+## deploy
+
+The `deploy` command group manages persistent deployments. The general workflow is `deploy init` to generate a spec file, then `deploy create` to create a deployment directory from the spec, then runtime commands like `deploy up` and `deploy down`.
+
+### deploy init
+
+Generate a deployment spec file from a stack definition:
+```
+$ laconic-so --stack <stack-name> deploy init --output <spec-file>
+```
+
+Options:
+- `--output` (required): write spec file here
+- `--config`: provide config variables for the deployment
+- `--config-file`: provide config variables in a file
+- `--kube-config`: provide a config file for a k8s deployment
+- `--image-registry`: provide a container image registry url for this k8s cluster
+- `--map-ports-to-host`: map ports to the host (`any-variable-random`, `localhost-same`, `any-same`, `localhost-fixed-random`, `any-fixed-random`)
+
+### deploy create
+
+Create a deployment directory from a spec file:
+```
+$ laconic-so --stack <stack-name> deploy create --spec-file <spec-file> --deployment-dir <dir>
+```
+
+Update an existing deployment in-place (preserving data volumes and env file):
+```
+$ laconic-so --stack <stack-name> deploy create --spec-file <spec-file> --deployment-dir <dir> --update
+```
+
+Options:
+- `--spec-file` (required): spec file to use
+- `--deployment-dir`: target directory for deployment files
+- `--update`: update an existing deployment directory, preserving data volumes and env file. Changed files are backed up with a `.bak` suffix. The deployment's `config.env` and `deployment.yml` are also preserved.
+- `--network-dir`: network configuration supplied in this directory
+- `--initial-peers`: initial set of persistent peers
+
+### deploy up
+
+Start a deployment:
+```
+$ laconic-so deployment --dir <deployment-dir> up
+```
+
+### deploy down
+
+Stop a deployment:
+```
+$ laconic-so deployment --dir <deployment-dir> down
+```
+Use `--delete-volumes` to also remove data volumes.
+
+### deploy ps
+
+Show running services:
+```
+$ laconic-so deployment --dir <deployment-dir> ps
+```
+
+### deploy logs
+
+View service logs:
+```
+$ laconic-so deployment --dir <deployment-dir> logs
+```
+Use `-f` to follow and `-n <count>` to tail.