idmp-attribute

attribute

Read ../idmp-shared/SKILL.md first.

Before any write: Follow the 🛑 Destructive op confirmation protocol. Read-only commands stay read-only here, but delete / write / patch flows still require the shared yes-gate.

Recommended shortcuts

Shortcut	Purpose
+list	Read attribute definitions before value or history work.
+get	Read one attribute's current value.
+data	Read multiple current values in one request.
+history	Read historical data for one attribute.

Recommended references

• references/idmp-attribute-evaluate-expression.md

Product-style workflow

1. Read definitions with attributes.
2. Read current values with data-get or data-post only when needed.
3. Run new-name without --ack-risk before creating an attribute.
4. Run attribute evaluate-expression create before saving a formula or expression.
5. Use write-data only when you need controlled test input on a metric-backed attribute.

Missing context to resolve first

Context	Why it must be resolved before create or write
Owner element	You need the final elementId before you can reserve names, create the attribute, or reread definitions and values.
Candidate attribute name	attribute attributes new-name only works after the owner is fixed.
Attribute type plan	You need the intended valueType and whether the attribute is only metadata, expression-backed, or a metric-backed writable reference.
Write target	Decide whether write-data should target an existing TDengine metric reference rather than the newly created attribute.
Verification and cleanup target	Decide how you will prove create success, how you will reread written data, and which temporary attribute must be deleted at the end.

Constrained live behaviors

• attribute attributes new-name only needs the owner scope, but attributes-post must use the final reserved name and a real valueType.
• The expression-preview command family is attribute evaluate-expression create, and the schema path is attribute.evaluate-expression.create; the older guessed attribute.attributes.evaluate-expression path is wrong.
• Older checks may still mention the guessed attribute.attributes.evaluate-expression path; use idmp-cli attribute evaluate-expression create --dry-run --ack-risk --params for the real request.
• attribute evaluate-expression create needs a request body with at least dataReferenceType and expression. The live-safe starter is {"dataReferenceType":"Formula","expression":"..."}; attributeId and uomId are optional context helpers, not substitutes for the formula text.
• A newly created generic attribute is not automatically a TDengine metric reference. attribute write-data create can fail with etda390037 unless the target attribute is backed by writable metric storage.
• In strict live validation, attribute historydata list should use explicit start and end bounds instead of relying on ambient defaults.
• Attribute create is not complete until attributes reread shows the new definition.
• Template-derived attributes are not generic scratch objects. If an attribute still has attrTempId, the generic attribute elements attributes-delete path is expected to reject the delete while the backing template exists.
• Temporary probe attributes should be deleted after the workflow, even when write-data validation used a different existing metric-backed attribute.

Evidence of completion

• A create is only complete when attribute elements attributes --params rereads the new definition under the same owner.
• A value probe is only complete when data-get, data-post, or bounded historydata list returns the intended attribute data.
• A write probe is only complete when the target is known to be metric-backed and the reread reflects the inserted row, not just the CLI success line.

Key commands

idmp-cli schema attribute.elements.attributes
idmp-cli attribute elements attributes --params '{"elementId":1}'

idmp-cli schema attribute.attributes.new-name
# new-name is read-only (reserves a name); no --ack-risk required
idmp-cli attribute attributes new-name --params '{"elementId":1}'

idmp-cli schema attribute.elements.attributes-post
idmp-cli attribute elements attributes-post --ack-risk --params '{"elementId":1}' --data '{"name":"probe-attribute","valueType":"Double"}'

idmp-cli schema attribute.evaluate-expression.create
idmp-cli attribute evaluate-expression create --params '{"elementId":1}' --data '{...}' --dry-run --ack-risk

idmp-cli schema attribute.attributes.data-get
idmp-cli attribute attributes data-get --params '{"elementId":1,"attributeId":2}'

idmp-cli schema attribute.historydata.list
idmp-cli attribute historydata list --params '{"elementId":1,"attributeId":2,"current":1,"size":20,"start":1704067200000,"end":1704153600000}'

Exception and failure handling

• If an attribute is not returned by attributes, do not guess the ID from older notes or scripts.
• If the definition exists but the current value is empty, check history before treating it as a product failure.
• If new-name returns a different candidate, use the reserved value instead of forcing the original name.
• If expression evaluation fails, fix the formula before create or update; do not save a broken expression first.
• If test writes are rejected with errors such as etda390037, switch to a known metric-backed attribute; do not assume the newly created attribute is writable.
• If delete fails because the attribute came from an attribute template, treat that as a scope boundary; do not keep retrying the generic element-attribute delete path.
• If the preview differs from the intended payload, stay read-only until the schema and permissions are correct.

Validation scenarios

1. Read attribute definitions with idmp-cli schema attribute.elements.attributes and idmp-cli attribute elements attributes --params '{"elementId":1}'.
2. Reserve a create-safe name with idmp-cli attribute attributes new-name --params '{"elementId":1}'.
3. Read one live value with idmp-cli attribute attributes data-get --params '{"elementId":1,"attributeId":2}'.
4. Create a probe attribute only after idmp-cli attribute attributes new-name --params '{"elementId":1}', then verify the create path with idmp-cli attribute elements attributes-post --ack-risk --params '{"elementId":1}' --data '{"name":"probe-attribute","valueType":"Double"}'.
5. Check history paging with idmp-cli attribute historydata list --params '{"elementId":1,"attributeId":2,"current":1,"size":20,"start":1704067200000,"end":1704153600000}', then use idmp-cli attribute write-data create --dry-run --ack-risk --params '{"elementId":1}' --data '{"probe":"example"}' only after confirming the target attribute is a writable metric reference and idmp-cli attribute evaluate-expression create --params '{"elementId":1}' --data '{"dataReferenceType":"Formula","expression":"AVG(${attributes['"'"'Current'"'"']})"}' --dry-run --ack-risk already succeeded.