The supervisor uses the following pattern for async module
initialization
```typescript
// module.ts
export const initialised = (async () => {
// do some async initialization
})();
// somewhere else
import * as module from 'module';
async function setup() {
await module.initialise;
}
```
The above pattern means that whenever the module is imported, the
initialisation procedure will be ran, which is an anti-pattern.
This converts any instance of this pattern into a function
```typescript
export const initialised = _.once(async () => {
// do some async initialization
});
```
And anywhere else on the code it replaces the call with a
```typescript
await module.initialised();
```
Change-type: patch
This change updates types and database format in order to allow
receiving the new format of the target state from the cloud and allow
applications to keep working.
This change also updates metadata in the containers, meaning services
will need to be restarted on supervisor update
Change-type: major
The API uses 304 as a mechanism for load management on target state
requests. This may cause that the supervisor receives a 304 response
without having received a copy of the target state first, leading to
issues. This change checks for an etag when receiving a 304, throwing an
exception otherwise.
Change-type: patch
During first time run of the supervisor, the target state is queried
by `reportInitialEnv`. Since this happens early on the initialization
process, this target state report is missed by any listeners and this
can lead to the initial target state not beeing applied (see #1455).
This PR ensures that target state is re-emitted if there were no
listeners setup on call to update.
Change-type: patch
Signed-off-by: Felipe Lalanne <felipe@balena.io>
Connects-to: #1455
