return {
  getToken() {
    return new Promise(async (resolve, reject) => {
      try {
        getRedisKey = function () {
          return `fhir-${fhirSettings.jwt.clientId}`;
        };

        const tokenEntry = await redis.hGetAll(getRedisKey());
        const currentTimeInSeconds = Math.floor(new Date().getTime() / 1000);

        if (tokenEntry.exp >= currentTimeInSeconds) {
          resolve(JSON.parse(tokenEntry.token));
          return;
        }

        // start the expiry base before we create a new token
        let expiryInSeconds = Math.floor(new Date().getTime() / 1000);

        // Define headers
        const headers = {
          alg: "RS256",
          typ: "JWT",
        };

        // Define your payload
        const payload = {
          iss: fhirSettings.jwt.client_id,
          sub: fhirSettings.jwt.client_id,
          aud: fhirSettings.token_url,
        };

        // Define token options (optional)
        const options = {
          expiresIn: "4m", // Token expires in 1 hour
          notBefore: "0",
          algorithm: "RS384",
          keyid: "iva_id_1234",
          jwtid: uuidv5("jwtid", fhirSettings.jwt.uuid_namespace),
        };

        let data = qs.stringify({
          grant_type: "client_credentials",
          client_assertion_type:
            "urn:ietf:params:oauth:client-assertion-type:jwt-bearer",
          client_assertion: jwt.sign(
            payload,
            fhirSettings.jwt.privateKey,
            options
          ),
        });

        let config = {
          method: "post",
          maxBodyLength: Infinity,
          url: fhirSettings.token_url,
          headers: {
            "Content-Type": "application/x-www-form-urlencoded",
          },
          data: data,
        };

        const result = await axios(config);

        if (result.status == 200) {
          expiryInSeconds += result.data.expires_in;
          console.log(
            `fhirInterface.getToken: Adding ${getRedisKey()} to redis with expiry=${new Date(
              expiryInSeconds * 1000
            )}`
          );
          await redis.hSet(getRedisKey(), "exp", expiryInSeconds);
          await redis.hSet(getRedisKey(), "token", JSON.stringify(result.data));
          resolve(result.data);
        } else {
          reject(result.status);
        }
      } catch (err) {
        console.log("fhirInterface.getToken: Error getting Token");
        console.log(err);
        if (err.response) {
          console.log(err.response.data); // => the response payload
        }
        reject(err);
      }
    });
  },
};