Add webhooks for invoices

[vincent-pochet]

We must add the webhook logic that will be triggered when the invoice is processed

[jdenquin]

• Add a webhook_url field on the organization.
• The payload should be signed.

[jdenquin]

• The payload should be like this one

  {
    "signature": "sig",
    "invoice": {
      "lago_id": "id",
      "incremental_id": "incremental_id",
      "customer": {
        "lago_id": "lago_id",
        "customer_id": "customer_id",
        "metadata": "metadata",
        ...
      },
      "subscription": {
        "lago_id": "lago_id",
        "anniversary_date": "anniversary_date",
        "status": "status"
        "plan": {
          "code": "code",
          "name": "name"
        }
      }
      "from_date": "from_date",
      "to_date": "to_date",
      "issuing_date": "issuing_date",
      "amount_cents": 100,
      "amount_currency": "EUR",
      "vat_amount_cents": 20,
      "vat_amount_currency": "EUR",
      "total_amount_cents": 100,
      "total_amount_currency": "EUR",
      "fees": [
        { // subscription fee
          "item": {
            "type": "subscription",
            "code": "code",
            "name": "name"
          },
          "amount_cents": 100,
          "amount_currency": "EUR",
          "vat_amount_cents": 20,
          "vat_amount_currency": "EUR"
        },
        {  // charge fee
          "item": {
            "type": "billable_metric",
            "code": "code",
            "name": "name"
          }
          "amount_cents": 100,
          "amount_currency": "EUR",
          "vat_amount_cents": 20,
          "vat_amount_currency": "EUR"
        }
      ]
    }
  }

[jdenquin]

• Add webhook_url on organizations
• Write the HTTP client to "consume" the webhook
• Add the signature logic
• Call the webhook URL when invoice is generated

[jdenquin]

Product Issue : https://github.com/getlago/lago-product/issues/5