“Progress isn’t made by early risers. It’s made by lazy men trying to find easier ways to do something.”
— Robert Heinlein
Last time, we completed the code to sync up the version records, so now all we have left to do is to do basically the same thing for the Update Set XML files attached to the version records. The attachments are a slightly different animal, though, so we can’t just clone what we have done before as we were able to do when using the application record process as a basis for creating the version record process. For one thing, the relationship between instances and their applications is one-to-many, just as the relationship between applications and their various versions is one-to-many. Theoretically, there should only be one attached Update Set XML file for any given version. Technically, there is nothing stopping someone from attaching additional files to a version record, and in the future we may, in fact, want to attach things to a version record like release notes or user guides, but there should only be one Update Set for each version.
One thing that I ended up doing was to go back into the syncVersions function and add in the capability to send the sys_id of the version record to the syncAttachments function. Because the sys_attachments table uses both a table_name and a table_sys_id property to link to the attachment to its record, I couldn’t really do any dot-walking to come up with a query to find the right attachment record. So I added a versionIdList in addition to the versionList to capture the sys_id of the version record along with the version number. The updated version of the syncVersions function now looks like this:
syncVersions: function(targetGR, thisApplication, thisInstance, remoteAppId) {
var versionList = [];
var versionIdList = [];
var versionGR = new GlideRecord('x_11556_col_store_member_application_version');
versionGR.addQuery('member_application.name', thisApplication);
versionGR.addQuery('member_application.provider.instance', thisInstance);
versionGR.query();
while (versionGR.next()) {
versionList.push(versionGR.getDisplayValue('version'));
versionIdList.push(versionGR.getUniqueValue());
}
if (versionList.length > 0) {
var request = new sn_ws.RESTMessageV2();
request.setHttpMethod('get');
request.setBasicAuth(this.CSU.WORKER_ROOT + targetGR.getDisplayValue('instance'), targetGR.getDisplayValue('token'));
request.setRequestHeader("Accept", "application/json");
request.setEndpoint('https://' + targetGR.getDisplayValue('instance') + '.service-now.com/api/now/table/x_11556_col_store_member_application_version?sysparm_fields=version%2Csys_id&sysparm_query=member_application%3D' + remoteAppId);
var response = request.execute();
if (response.haveError()) {
gs.error('InstanceSyncUtils.syncVersions - Error returned from attempt to fetch version list: ' + response.getErrorCode() + ' - ' + response.getErrorMessage());
} else if (response.getStatusCode() == '200') {
var jsonString = response.getBody();
var jsonObject = {};
try {
jsonObject = JSON.parse(jsonString);
} catch (e) {
gs.error('InstanceSyncUtils.syncVersions - Unparsable JSON string returned from attempt to fetch version list: ' + jsonString);
}
if (Array.isArray(jsonObject.result)) {
for (var i=0; i<versionList.length; i++) {
var thisVersion = versionList[i];
var thisVersionId = versionIdList[i];
var remoteVerId = '';
for (var j=0; j<jsonObject.result.length && remoteVerId == ''; j++) {
if (jsonObject.result[j].version == thisVersion) {
remoteVerId = jsonObject.result[j].sys_id;
}
}
if (remoteVerId == '') {
remoteVerId = this.sendVersion(targetGR, thisVersion, thisApplication, thisInstance, remoteAppId);
}
this.syncAttachments(targetGR, thisVersionId, thisVersion, thisApplication, thisInstance, remoteVerId);
}
} else {
gs.error('InstanceSyncUtils.syncVersions - Invalid response body returned from attempt to fetch version list: ' + response.getBody());
}
} else {
gs.error('InstanceSyncUtils.syncVersions - Invalid HTTP response code returned from attempt to fetch version list: ' + response.getStatusCode());
}
} else {
gs.info('InstanceSyncUtils.syncVersions - No versions to sync for application ' + thisApplication + ' on instance ' + thisInstance);
}
}
With the sys_id in hand, we could now build a simple query to fetch the attachment record.
var attachmentList = [];
var attachmentGR = new GlideRecord('sys_attachment');
attachmentGR.addQuery('table_name', 'x_11556_col_store_member_application_version');
attachmentGR.addQuery('table_sys_id', thisVersionId);
attachmentGR.addQuery('content_type', 'CONTAINS', 'xml');
attachmentGR.query();
while (attachmentGR.next()) {
attachmentList.push(attachmentGR.getUniqueValue());
}
I’m still building up a list here, even though there should only be one XML attachment for each version record, but since I copied most of the code from the version function, I just left that in place. In practice, this should always be a list of one item. Assuming we have an attachment (which we always should!), we need to check the target instance to see if they already have it as well. For that, of course, we resort to making another REST API call.
var request = new sn_ws.RESTMessageV2();
request.setHttpMethod('get');
request.setBasicAuth(this.CSU.WORKER_ROOT + targetGR.getDisplayValue('instance'), targetGR.getDisplayValue('token'));
request.setRequestHeader("Accept", "application/json");
request.setEndpoint('https://' + targetGR.getDisplayValue('instance') + '.service-now.com/api/now/table/sys_attachment?sysparm_fields=sys_id&sysparm_query=table_name%3Dx_11556_col_store_member_application_version%5Etable_sys_id%3D' + remoteVerId + '%5Econtent_typeCONTAINSxml');
Once we build the request, we execute it and check the results.
var response = request.execute();
if (response.haveError()) {
gs.error('InstanceSyncUtils.syncAttachments - Error returned from attempt to fetch attachment list: ' + response.getErrorCode() + ' - ' + response.getErrorMessage());
} else if (response.getStatusCode() == '200') {
var jsonString = response.getBody();
var jsonObject = {};
try {
jsonObject = JSON.parse(jsonString);
} catch (e) {
gs.error('InstanceSyncUtils.syncAttachments - Unparsable JSON string returned from attempt to fetch attachment list: ' + jsonString);
}
if (Array.isArray(jsonObject.result)) {
if (jsonObject.result.length == 0) {
this.sendAttachment(targetGR, attachmentList[0], remoteVerId, thisVersion, thisApplication);
}
} else {
gs.error('InstanceSyncUtils.syncAttachments - Invalid response body returned from attempt to fetch attachment list: ' + response.getBody());
}
} else {
gs.error('InstanceSyncUtils.syncAttachments - Invalid HTTP response code returned from attempt to fetch attachment list: ' + response.getStatusCode());
}
All together, the new syncAttachments function looks like this:
syncAttachments: function(targetGR, thisVersionId, thisVersion, thisApplication, thisInstance, remoteVerId) {
var attachmentList = [];
var attachmentGR = new GlideRecord('sys_attachment');
attachmentGR.addQuery('table_name', 'x_11556_col_store_member_application_version');
attachmentGR.addQuery('table_sys_id', thisVersionId);
attachmentGR.addQuery('content_type', 'CONTAINS', 'xml');
attachmentGR.query();
while (attachmentGR.next()) {
attachmentList.push(attachmentGR.getUniqueValue());
}
if (attachmentList.length > 0) {
var request = new sn_ws.RESTMessageV2();
request.setHttpMethod('get');
request.setBasicAuth(this.CSU.WORKER_ROOT + targetGR.getDisplayValue('instance'), targetGR.getDisplayValue('token'));
request.setRequestHeader("Accept", "application/json");
request.setEndpoint('https://' + targetGR.getDisplayValue('instance') + '.service-now.com/api/now/table/sys_attachment?sysparm_fields=sys_id&sysparm_query=table_name%3Dx_11556_col_store_member_application_version%5Etable_sys_id%3D' + remoteVerId + '%5Econtent_typeCONTAINSxml');
var response = request.execute();
if (response.haveError()) {
gs.error('InstanceSyncUtils.syncAttachments - Error returned from attempt to fetch attachment list: ' + response.getErrorCode() + ' - ' + response.getErrorMessage());
} else if (response.getStatusCode() == '200') {
var jsonString = response.getBody();
var jsonObject = {};
try {
jsonObject = JSON.parse(jsonString);
} catch (e) {
gs.error('InstanceSyncUtils.syncAttachments - Unparsable JSON string returned from attempt to fetch attachment list: ' + jsonString);
}
if (Array.isArray(jsonObject.result)) {
if (jsonObject.result.length == 0) {
this.sendAttachment(targetGR, attachmentList[0], remoteVerId, thisVersion, thisApplication);
}
} else {
gs.error('InstanceSyncUtils.syncAttachments - Invalid response body returned from attempt to fetch attachment list: ' + response.getBody());
}
} else {
gs.error('InstanceSyncUtils.syncAttachments - Invalid HTTP response code returned from attempt to fetch attachment list: ' + response.getStatusCode());
}
} else {
gs.info('InstanceSyncUtils.syncAttachments - No attachments to sync for version ' + thisVersionId + ' of application ' + thisApplication + ' on instance ' + thisInstance);
}
}
If there was no matching attachment on the target instance, we need to send it over, which we accomplish with a new sendAttachment function modeled after the earlier sendVersion function.
sendAttachment: function(targetGR, attachmentId, remoteVerId, thisVersion, thisApplication) {
var attachmentGR = new GlideRecord('sys_attachment');
if (attachmentGR.get(attachmentId)) {
gs.info('InstanceSyncUtils.sendAttachment - Sending attachment ' + attachmentGR.getDisplayValue('file_name') + ' from version ' + thisVersion + ' of application ' + thisApplication + ' to target instance ' + targetGR.getDisplayValue('instance'));
var result = this.CSU.pushAttachment(attachmentGR, targetGR, remoteVerId);
if (result.error) {
gs.error('InstanceSyncUtils.sendAttachment - Error occurred attempting to push attachment ' + attachmentGR.getDisplayValue('file_name') + ' from version ' + thisVersion + ' of application ' + thisApplication + ' to target instance ' + targetGR.getDisplayValue('instance') + ': ' + result.errorCode + '; ' + result.errorMessage);
} else if (result.status != 200 && result.status != 201) {
gs.error('InstanceSyncUtils.sendAttachment - Invalid HTTP response code returned from attempt to push attachment ' + attachmentGR.getDisplayValue('file_name') + ' from version ' + thisVersion + ' of application ' + thisApplication + ' to target instance ' + targetGR.getDisplayValue('instance') + ': ' + result.status);
} else if (!result.obj) {
gs.error('InstanceSyncUtils.sendAttachment - Invalid response body returned from attempt to push attachment ' + attachmentGR.getDisplayValue('file_name') + ' from version ' + thisVersion + ' of application ' + thisApplication + ' to target instance ' + targetGR.getDisplayValue('instance') + ': ' + result.body);
}
}
}
That completes all of the coding for the process of syncing all of the Client instances with the Host instance. If all is working correctly, it should ensure that all member instances have the same list of instances, the same list of applications from each contributing instance, the same list of versions for each application, and the associated Update Set XML file attachment for each version. Of course, there is still quite a bit of testing to do to make sure that all of this works as intended, so I will put together yet another Update Set and talk about how folks can help test all of this out in our next installment.
