Function: Basic cURL GET

Enterprise Edition

Goal: Perform a simple cURL GET using an external REST endpoint.

This function basicCurlGet communicates with a public REST service.
Requires Eventing Storage (or metadata collection) and a "source" collection.
Needs a Binding of type URL Alias (as documented in the Scriptlet).
Will operate on any mutation of the KEY "make_curl_request::1".
The actual cURL request from the Eventing Function will be equivalent to either of the following (but test to make sure the service is live):
```
curl -q -X GET 'https://api.frankfurter.app/latest'
curl -q -X GET 'https://api.ratesapi.io/api/latest'
```
Only logs the REST response JSON payload to the Application log file.
For a more complete example using this public REST endpoint (or to make your own service), refer to External REST via cURL GET.

basicCurlGet
Input Data/Mutation
Output Data/Logged

// To run configure the settings for this Function, basicCurlGet, as follows:
//
// Version 7.1+
//   "Function Scope"
//     *.* (or try bulk.data if non-privileged)
// Version 7.0+
//   "Listen to Location"
//     bulk.data.source
//   "Eventing Storage"
//     rr100.eventing.metadata
//   Binding(s)
//    1. "binding type", "alias name...",   "URL...",                       "misc.",
//       "URL alias",    "exchangeRateApi", "https://api.frankfurter.app/", "no auth"
//
// Version 6.X
//   "Source Bucket"
//     source
//   "MetaData Bucket"
//     metadata
//   Binding(s)
//    1. "binding type", "alias name...",   "URL...",                       "misc.",
//       "URL alias",    "exchangeRateApi", "https://api.frankfurter.app/", "no auth"

function OnUpdate(doc, meta) {
    // You would typically filter to mutations of interest
    if (meta.id !== 'make_curl_request::1') return;
    try {
        // only make a cURL GET request id we see a mutation on the above KEY
        var request = { path: "latest" }; // easiest API call could supply YYYY-MM-DD
        //  perform the cURL request using the URL alias from the settings
        var response = curl('GET', exchangeRateApi, request);
        if (response.status != 200 && response.status != 302) {
            log("cURL GET failed response.status:",response.status)
        } else {
            log("cURL GET success, response.body:",response.body)
            // optional write to a bucket - requires a binding alias in settings
            // dst_col[meta.id] = response.body;
        }
    } catch (e) {
        log("cURL request had an exception:",e)
    }
}

INPUT: KEY make_curl_request::1

{
  "anything": 1
}

2021-07-18T18:13:57.566-07:00 [INFO] "cURL GET success, response.body:"
{
    "amount": 1,
    "base": "EUR",
    "date": "2021-07-16",
    "rates": {
        "AUD": 1.5907,
        "BGN": 1.9558,
        "BRL": 6.0146,
        "CAD": 1.4856,
        "CHF": 1.0853,
        "CNY": 7.6373,
        "CZK": 25.538,
        "DKK": 7.4381,
        "GBP": 0.85298,
        "HKD": 9.1684,
        "HRK": 7.4968,
        "HUF": 359.73,
        "IDR": 17083,
        "ILS": 3.8796,
        "INR": 88.03,
        "ISK": 145.9,
        "JPY": 130.03,
        "KRW": 1347.94,
        "MXN": 23.459,
        "MYR": 4.9681,
        "NOK": 10.3878,
        "NZD": 1.6836,
        "PHP": 59.364,
        "PLN": 4.5867,
        "RON": 4.9285,
        "RUB": 87.52,
        "SEK": 10.2428,
        "SGD": 1.5993,
        "THB": 38.669,
        "TRY": 10.0521,
        "USD": 1.1802,
        "ZAR": 16.984
    }
}