kubernetes provider is used,
container modules can be configured to hot-reload their running services when the module's sources change (i.e. without redeploying). In essence, hot-reloading copies syncs files into the appropriate running containers (local or remote) when code is changed by the user, and optionally runs a post-sync command inside the container.
For example, services that can be run with a file system watcher that automatically updates the running application process when sources change (e.g. nodemon, Django, Ruby on Rails, and many other web app frameworks) are a natural fit for this feature.
Currently, services are only deployed with hot reloading enabled when their names are passed to the
--hot option via
garden deploy or
garden dev commands (e.g.
garden dev --hot=foo-service,bar-service). If these services don't belong to a module defining a
hotReload configuration (see below for an example), an error will be thrown if their names are passed to the
You can also pass
--hot-reload=*) to deploy all compatible services with hot reloading enabled (i.e. all services belonging to a module that defines a
Subsequently deploying a service belonging to a module configured for hot reloading via
garden deploy (without the watch flag) results in the service being redeployed in standard configuration.
Since hot reloading is triggered via Garden's file system watcher, hot reloading only occurs while a watch-mode Garden command is running.
Following is an example of a module configured for hot reloading:
kind: Moduledescription: My Test Servicename: test-servicetype: containerhotReload:sync:- target: /app/services:- name: test-serviceargs: [npm, start] # runs `node main.js`hotReloadArgs: [npm, run, dev] # runs `nodemon main.js`
In the above, the
hotReload field specifies the destination path inside the running container that the module's (top-level) directory (where its
garden.yml resides) is synced to.
Note that only files tracked in version control are synced, e.g. respecting
source is specified along with
target, that subpath in the module's directory is synced to the target instead of the default of syncing the module's top-level directory.
You can configure several such
target pairs, but note that the
source paths must be disjoint, i.e. a
source path may not be a subdirectory of another
source path within the same module. Here's an example:
hotReload:sync:- source: /footarget: /app/foo- source: /bartarget: /app/bar
hotReloadArgs specifies the arguments to use to run the container (when deployed with hot reloading enabled). If no
hotReloadArgs are specified,
args is also used to run the container when the service is deployed with hot reloading enabled
postSyncCommand can also be added to a module's hot reload configuration. This command is executed inside the running container during each hot reload, after syncing is completed (as the name suggests).
Following is a snippet from the
hot-reload-post-sync-command example project. Here, a
postSyncCommand is used to
touch a file, updating its modification time. This way,
nodemon only has to watch one file to keep the running application up to date. See the
hot-reload-post-sync-command example for more details and a fuller discussion.
kind: Moduledescription: Node greeting servicename: node-servicetype: containerhotReload:sync:- target: /app/postSyncCommand: [touch, /app/hotreloadfile]services:- name: node-serviceargs: [npm, start]hotReloadArgs: [npm, run, dev] # Runs modemon main.js --watch hotreloadfile...