The Resin Supervisor is resin.io's agent that runs on devices. Its main role is to ensure your app is running, and keep communications with the Resin API server.
The Supervisor itself has its own API, with means for user applications to communicate and execute some special actions that affect the host OS or the application itself. There are two main ways for the application to interact with the Supervisor: the update lockfile and the HTTP API.
Only Supervisors after version 1.1.0 have this functionality, and some of the endpoints appeared in later versions (we've noted it down where this is the case). Supervisor version 1.1.0 corresponds to OS images downloaded after October 14th 2015.
The supervisor exposes an HTTP API on port 48484 (`RESIN_SUPERVISOR_PORT`).
**All endpoints require an apikey parameter, which is exposed to the application as `RESIN_SUPERVISOR_API_KEY`.**
The full address for the API, i.e. `"http://127.0.0.1:48484"`, is available as `RESIN_SUPERVISOR_ADDRESS`. **Always use these variables when communicating via the API, since address and port could change**.
Alternatively, the Resin API (api.resin.io) has a proxy endpoint at `POST /supervisor/<url>` (where `<url>` is one of the API URLs described below) from which you can send API commands to the supervisor remotely, using your Auth Token instead of your API key. Commands sent through the proxy require an `appId` and/or `deviceId` parameter in the body, and default to POST requests unless you specify a `method` parameter (e.g. "GET").
The API is versioned (currently at v1), except for `/ping`.
You might notice that the formats of some responses differ. This is because they were implemented later, and in Go instead of node.js.
Here's the full list of endpoints implemented so far. In all examples, replace everything between `< >` for the corresponding values.
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### GET /ping
Responds with a simple "OK", signaling that the supervisor is alive and well.
#### Examples:
From the app on the device:
```bash
$ curl -X GET --header "Content-Type:application/json" \
When the device's connection to the Resin VPN is down, by default the device performs a TCP ping heartbeat to check for connectivity. This endpoint enables such TCP ping in case it has been disabled (see DELETE /v1/tcp-ping).
When successful, responds with an empty 204:
#### Examples:
From the app on the device:
```bash
$ curl -X POST --header "Content-Type:application/json" \
When the device's connection to the Resin VPN is down, by default the device performs a TCP ping heartbeat to check for connectivity. This endpoint disables such TCP ping.
Invalidates the current `RESIN_SUPERVISOR_API_KEY` and generates a new one. Responds with the new API key, but **the application will be restarted on the next update cycle** to update the API key environment variable.
#### Examples:
From the app on the device:
```bash
$ curl -X POST --header "Content-Type:application/json" \
*`download_progress`: Amount of the application image that has been downloaded, expressed as a percentage. If the update has already been downloaded, this will be `null`.
*`update_pending`: This one is not reported to the Resin API. It's a boolean that will be true if the supervisor has detected there is a pending update.
*`update_downloaded`: Not reported to the Resin API either. Boolean that will be true if a pending update has already been downloaded.
*`update_failed`: Not reported to the Resin API. Boolean that will be true if the supervisor has tried to apply a pending update but failed (i.e. if the app was locked, there was a network failure or anything else went wrong).
{"api_port":48484,"ip_address":"192.168.0.114 10.42.0.3","commit":"414e65cd378a69a96f403b75f14b40b55856f860","status":"Downloading","download_progress":84,"os_version":"Resin OS 1.0.4 (fido)","supervisor_version":"1.6.0","update_pending":true,"update_downloaded":false,"update_failed":false}
