Function: Advanced DELETE operation
March 23, 2025
Goal: Perform the Advanced DELETE operation where Eventing interacts with the Data service.
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This function advancedDeleteOp merely demonstrates the Advanced DELETE operation.
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Requires Eventing Storage (or metadata collection) and a "source" collection.
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Needs a Binding of type "bucket alias" (as documented in the Scriptlet).
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Will operate on any mutation where doc.type === "control_adv_delete".
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Always tries to insert the test document, any insert error will be ignored.
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There are 4 modes of operation: no_cas, bad_cas, no_key, and good_cas.
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For more information refer to Advanced DELETE operation in the detailed documentation.
javascriptCopy// To run configure the settings for this Function, advancedDeleteOp, 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...", "bucket.scope.collection", "Access"
// "bucket alias", "src_col", "bulk.data.source", "read and write"
//
// Version 6.6.1
// "Source Bucket"
// source
// "MetaData Bucket"
// metadata
// Binding(s)
// 1. "binding type", "alias name...", "bucket", "Access"
// "bucket alias", "src_col", "source", "read and write"
function OnUpdate(doc, meta) {
if (!meta.id.startsWith("control_adv_delete")) return;
log('input meta', meta);
log('input doc ', doc);
// Setup, make sure we have our doc to "delete", ignore any errors
couchbase.insert(src_col,{"id":"test_adv_delete:" + doc.ins_id},{"a:": 1});
var new_meta;
if (doc.mode && doc.mode === "no_cas") {
// Here we pass no CAS it will always succeed
new_meta = {"id":"test_adv_delete:" + doc.ins_id};
}
if (doc.mode && doc.mode === "bad_cas") {
// Here we pass a non-matching CAS it will always fail
new_meta = {"id":"test_adv_delete:" + doc.ins_id, "cas":"1111111111111111111"};
}
if (doc.mode && doc.mode === "good_cas") {
// Here we will pass the matching or current CAS it will succeed
var tmp_r = couchbase.get(src_col,{"id":"test_adv_delete:" + doc.ins_id});
if (tmp_r.success) {
// Here we use the current CAS just read via couchbase.get(...)
new_meta = {"id":"test_adv_delete:" + doc.ins_id, "cas": tmp_r.meta.cas};
} else {
log('Cannot delete due to no such key',"test_adv_delete:" + doc.ins_id);
return;
}
}
if (doc.mode && doc.mode === "no_key") {
// Remove (delete with a basic bucket op) so that we have: no such key
delete src_col["test_adv_delete:" + doc.ins_id]
new_meta = {"id":"test_adv_delete:" + doc.ins_id};
}
var result = couchbase.delete(src_col,new_meta);
if (result.success) {
log('success adv. delete: result',result);
} else {
log('failure adv. delete: id',new_meta.id,'result',result);
}
}
jsonCopyMutation #1
INPUT: KEY control_adv_delete::1
{
"id": 1,
"type": "control_adv_delete",
"ins_id": 10,
"mode": "no_cas"
}
Mutation #2
INPUT: KEY control_adv_delete::2
{
"id": 2,
"type": "control_adv_delete",
"ins_id": 10,
"mode": "bad_cas"
}
Mutation #3
INPUT: KEY control_adv_delete::3
{
"id": 3,
"type": "control_adv_delete",
"ins_id": 10,
"mode": "no_key"
}
Mutation #4
INPUT: KEY control_adv_delete::4
{
"id": 4,
"type": "control_adv_delete",
"ins_id": 10,
"mode": "good_cas"
}
We do four (4) deletion attempts the second fails due to a CAS missmatch and the third fails due to no such key.
jsonCopyLogs from Mutation #1
2021-01-08T11:45:02.897-08:00 [INFO] "input meta"
{
"cas": "1610134800219308032",
"id": "control_adv_delete::1",
"expiration": 0,
"flags": 33554438,
"vb": 221,
"seq": 1
}
2021-01-08T11:45:02.898-08:00 [INFO] "input doc "
{
"id": 1,
"type": "control_adv_delete",
"ins_id": 10,
"mode": "no_cas"
}
2021-01-08T11:45:02.899-08:00 [INFO] "success adv. delete: result"
{
"meta": {
"id": "test_adv_delete:10",
"cas": "1610135102898962432"
},
"success": true
}
Logs from Mutation #2
2021-01-08T11:46:11.225-08:00 [INFO] "input meta"
{
"cas": "1610135171148152832",
"id": "control_adv_delete::2",
"expiration": 0,
"flags": 33554438,
"vb": 468,
"seq": 3
}
2021-01-08T11:46:11.225-08:00 [INFO] "input doc "
{
"id": 2,
"type": "control_adv_delete",
"ins_id": 10,
"mode": "bad_cas"
}
2021-01-08T11:46:11.228-08:00 [INFO] "failure adv. delete: id" "test_adv_delete:10" "result"
{
"error": {
"code": 272,
"name": "LCB_KEY_EEXISTS",
"desc": "The document key exists with a CAS value different than specified",
"cas_mismatch": true
},
"success": false
}
Logs from Mutation #3
2021-01-08T11:52:51.520-08:00 [INFO] "input meta"
{
"cas": "1610135571485425664",
"id": "control_adv_delete::3",
"expiration": 0,
"flags": 33554438,
"vb": 723,
"seq": 5
}
2021-01-08T11:52:51.520-08:00 [INFO] "input doc "
{
"id": 3,
"type": "control_adv_delete",
"ins_id": 10,
"mode": "no_key"
}
2021-01-08T11:52:51.522-08:00 [INFO] "failure adv. delete: id" "test_adv_delete:10" "result"
{
"error": {
"code": 272,
"name": "LCB_KEY_ENOENT",
"desc": "The document key does not exist on the server",
"key_not_found": true
},
"success": false
}
Logs from Mutation #4
2021-01-08T11:53:36.070-08:00 [INFO] "input meta"
{
"cas": "1610135616063602688",
"id": "control_adv_delete::4",
"expiration": 0,
"flags": 33554438,
"vb": 183,
"seq": 3
}
2021-01-08T11:53:36.070-08:00 [INFO] "input doc "
{
"id": 4,
"type": "control_adv_delete",
"ins_id": 10,
"mode": "good_cas"
}
2021-01-08T11:53:36.074-08:00 [INFO] "success adv. delete: result"
{
"meta": {
"id": "test_adv_delete:10",
"cas": "1610135616073760768"
},
"success": true
}