synowebapi: Stopping Container Manager projects

Here’s how to use synowebapi for stopping (and starting) projects in Container Manager on a Synology NAS.

Background

To back up Forgejo and Immich on my Synology NAS, I’ve got a scheduled task that runs at 3am that uses docker-compose stop to ensure that nothing’s running before backing up the databases. This has the unfortunate side effect that I get a bunch of “Container forgejo-postgres-1 stopped unexpectedly.” warnings, one for each container.

synowebapi

The Synology Diskstation software provides a synowebapi command line tool that you can run as root on the NAS itself which invokes various APIs “correctly”, so I figured I’d see if I could use that instead.

To figure out which API calls the normal web console uses, I opened Firefox Developer Tools and then navigated to the “forgejo” project in Container Manager. It was already stopped, so I clicked the “Start” button. In the Network tab, this showed a request to SYNO.Docker.Project with the following content:

{
	"api": "SYNO.Docker.Project",
	"method": "start_stream",
	"version": "1",
	"id": "\"bddfea05-8010-4dd9-a1c8-8d93867040b8\""
}

This is promising, except that it uses an ID rather than a name. On a hunch, I decided to try the following command:

synowebapi --exec api=SYNO.Docker.Project version=1 method=list | jq

This gave me the following output (various bits ellided):

{
  "data": {
    //...
    "bddfea05-8010-4dd9-a1c8-8d93867040b8": {
      "containerIds": [
      ],
      "id": "bddfea05-8010-4dd9-a1c8-8d93867040b8",
      "name": "forgejo",
      //...
    },
    //...
  }
}

Bingo.

So we can find the project ID with the following:

# synowebapi --exec api=SYNO.Docker.Project version=1 method=list 2>/dev/null | jq -r '.data[] | select(.name == "forgejo") | .id'
bddfea05-8010-4dd9-a1c8-8d93867040b8

Rewriting the scripts

This means that my start.sh script can look like this:

#!/bin/bash

forgejo_project_id=bddfea05-8010-4dd9-a1c8-8d93867040b8
immich_project_id=8ec29f37-76bb-49c9-bf07-9b30403fed54

synowebapi --exec api=SYNO.Docker.Project version=1 method=start "id=\"$forgejo_project_id\""
synowebapi --exec api=SYNO.Docker.Project version=1 method=start "id=\"$immich_project_id\""

Note the awkward quoting (which you can actually see in the original captured request). Without this, you get a “Not a json value” warning from synowebapi. Worse than that, it sometimes fails – I suspect that it thinks that 8ec29f37... is a number in scientific notation, rather than a string. Therefore: quotes.

Yes, I could have put the jq query in the script, but the IDs aren’t going to change, so there’s little point.

The stop.sh script is almost identical, except that it has method=stop.