sendInvitation: showcasing using mongoose . The Transaction considers the success of send email message to Rabbit

sendInvitation.js

const sendInvitation = async (parent, { invite }, ctx, info) => {
  try {
    const blackListEmail = req.user.email;

    await isInviteToSendValid(invite, blackListEmail);
  } catch (err) {
    return formatYupError(err);
  }

  let { companyName, email, message } = invite;

  //check if an invitation is already sent
  const db_session = await global.dbConnection.startSession();

  db_session.startTransaction();

  try {
    let inviteToSave = {
      companyName: invite.companyName,
      message: invite.message,
      email: invite.email,
      status: 'Pending',
      dateModified: moment().format('MMM DD YY')
    };

    let invitingCompany = await Company.find({
      _id: ObjectId(req.user.company)
    })
      .select(
        'invitations businessType businessArea companyIsVerified country companyName myAgents myImporters myVendors image'
      )
      .session(db_session)
      .exec();

    if (invitingCompany) {
      let existingInvitation = find(invitingCompany.invitations, function(
        invite
      ) {
        return String(invite.email) == String(email);
      });

      if (existingInvitation) {
        if (
          existingInvitation.status == 'Confirmed' ||
          existingInvitation.status == 'Cancelled'
        ) {
          await db_session.abortTransaction();
          return [
            errors.inviteAlreadyCancelledOrConfirmed({
              companyName: existingInvitation.companyName,
              status: existingInvitation.status
            })
          ];
        } else {
          existingInvitation.dateModified = moment().format('MMM DD YY');
        }
      } else {
        //new Invitation
        invitingCompany.invitations.push(inviteToSave);
      }
    } else {
      await db_session.abortTransaction();
      return [errors.errorSendingInvitation()];
    }

    let save_invitation = await invitingCompany.save({ session: db_session });
    if (!save_invitation) {
      await db_session.abortTransaction();
      return [errors.errorSendingInvitation()];
    } else {
      //send email and commit the transaction.
      let a =
        base_url_web + `register/invite/${companyId}/${inviteToSave.email}`;
      let accept_a =
        base_url_web +
        `register/existing/${invitingCompany._id}/${inviteToSave.email}/accept`;
      let decline_a =
        base_url_web +
        `register/existing/${invitingCompany._id}/${inviteToSave.email}/decline`;
      let companyLogo = invitingCompany.image;
      let rfpiCount = 0;
      let piCount = 0;

      if (invitingCompany.businessType == 'Importer') {
        rfpiCount = await PI.countDocuments({ importerId: req.user.company });
        piCount = await PI.countDocuments({
          importerId: req.user.company,
          status: { $eq: 'Converted to PI' }
        });
      } else if (invitingCompany.businessType == 'Exporter') {
        rfpiCount = await PI.countDocuments({ vendorId: req.user.company });
        piCount = await PI.countDocuments({
          vendorId: req.user.company,
          status: { $eq: 'Converted to PI' }
        });
      }

      let payload = {
        email: inviteToSave.email,
        subject: `Invitation to join or Connect on LightTrading Platform`,
        invited: inviteToSave.companyName,
        inviter: invitingCompany.companyName,
        inviterBussType: invitingCompany.businessType,
        inviterBussArea: invitingCompany.businessArea,
        inviterConnections:
          invitingCompany.myAgents.length +
          invitingCompany.myVendors.length +
          invitingCompany.myImporters.length,
        inviterRFPI: rfpiCount,
        inviterPI: piCount,
        inviterCompletedOrder: 0,
        inviterReview: 0,
        inviterVerified: invitingCompany.companyIsVerified,
        inviterBussCountry: invitingCompany.country,
        message: inviteToSave.message,
        logo: companyLogo,
        link: a,
        link_accept: accept_a,
        link_decline: decline_a,
        eventId: new mongoose.mongo.ObjectId(),
        dateCreated: moment(),
        eventType: eventTypeEnums.invitationSent,
        actionUrl: '',
        summary: `Invitation sent to ${inviteToSave.companyName} to connect on light trading.`
      };

      let paramRabbit = {
        chanelName: ltChanel.chanelName,
        exchange: eventTypeEnums.invitationSent, //event name
        routingKey:
          eventTypeEnums.invitationSent +
          '.' +
          invitingCompany._id.toString() +
          '.*'
      };

      let send_email = await publishToRabbit(
        paramRabbit,
        new Buffer(JSON.stringify(payload)),
        { persistent: true }
      );
      if (send_email) {
        await db_session.commitTransaction();
        return inviteToSave;
      } else {
        await db_session.abortTransaction();
        return [errors.errorSendingInvitation()];
      }
    }
  } catch (e) {
    await db_session.abortTransaction();
    await db_session.endSession();

    throw e.message;
  } finally {
    await db_session.endSession();
  }
};