JWT Token generation via Lua script

[riza-khan]

I'm trying to get the access-token from Docusign like so:

### access-token

< {%
   -- lua
   local crypto = require("kulala.cmd.crypto")
   local header = { alg = "RS256", typ = "JWT" }
   
   local payload = {
   iss = "fe6........",
   sub = "5e....",
   scope = "signature impersonation",
   aud = "account-d.docusign.com",
   iat = os.time(),
   exp = os.time() + 4000
   }
   
   local key = "-----BEGIN RSA PRIVATE KEY-----MIIE...-----END RSA PRIVATE KEY-----"
   
   local jwt = crypto.jwt_encode(header, payload, key)
   client.global.jwt = jwt
%}

POST {{DOCUSIGN_AUTH_BASE_URL}}/oauth/token HTTP/1.1
Content-Type: application/x-www-form-urlencoded

grant_type=urn:ietf:params:oauth:grant-type:jwt-bearer&assertion={{jwt}}

But I keep getting this error:

{
  "error": "invalid_grant",
  "error_description": "no_valid_keys_or_signatures"
}

I think the problem is the key I am using, as in the formatting of it. A better way to import in lua?

When I decode the token generated from the above script, I do notice the scope is malformed:

 "scope": "signatureimpersonation",

[riza-khan]

I would actually prefer the Kulala way of doing things:

But can't seem to get the flow to work.

             "docusign": {
          "Acquire Automatically": true,
          "Auth URL": "https://account-d.docusign.com/oauth/token",
          "Client ID": "fe...",
          "Expires In": 4000,
          "Grant Type": "Authorization Code",
          "JWT": {
            "header": {
              "alg": "RS256",
              "typ": "JWT"
            },
            "payload": {
              "iss": "04....",
              "sub": "d77....",
              "scope": "signature impersonation",
              "aud": "account-d.docusign.com"
            }
          },
          "PKCE": [
            true,
            {
              "Code Challenge Method": "SHA-256",
              "Code Verifier": "YYL..."
            }
          ],
          "Password": "",
          "Redirect URL": "http://localhost",
          "Revoke URL": "",
          "Scope": "signature impersonation",
          "Token URL": "https://account-d.docusign.com/oauth/token",
          "Type": "JWT",
          "Use ID Token": false,
          "Username": ""
        },

I entered the private_key in the private.env.json like so:

{
          "auth_data": [],
          "private_key": "-----BEGIN RSA PRIVATE KEY-----M...-----END RSA PRIVATE KEY-----"
        },

But didn't take:

Failed to: acquire token. Error parsing authentication response:
Expected value but found invalid token at character 1

[riza-khan]

Followed this and got it to work in kulala but I have another problem, but will ask in another thread.