For data that is synchronized to the cloud, you can create custom metrics from the data stream. These metrics can then be displayed or graphed in the Device Manager.
Ioto metrics automatically calculate statistics for the last "5 minutes", "hour", "day", "week" "month", or "year". For each timespan, you can query the average, minimum, maximum or sum value for the metric.
Metrics are created and subsequently queried by a set of naming properties including:
- metric name
The namespace is a global name to group related metrics. Currently, this must be set to
The metric name is the specific metric name. For example: a device's
The dimensions select specific instances of a metric. For example, each device may have a
temperature metric and we may also have an overall device pool average
In the process section for a model, define a metrics array of metric definitions. Each definition selects a data item value to be converted to a metric.
This will create a
temperature metric from the item's
Metric definitions may contain the following properties:
||Metric namespace for the metric. Must be set to 'Embedthis/Device'.|
||Array of metrics to create. Array metric entries may contain field attribute names or a map of a field attribute to a metric name.|
||Conditional expression to select items for which to create metrics.|
||Metric buffering directives. Defaults to null|
namespace scopes the metrics and must be set to 'Embedthis/Device'. Other namespaces may be supported in the future.
fields property contains an array with one or more metric definitions. Each definition may be either:
- An item attribute name which is used to identify the value AND to name the metric.
- A map of an item attribute name to a metric name.
This would create three metrics using the item's
speed attributes. The metrics would take the same name.
This would create the metrics:
Level from the
speed item attributes.
where property can be used to select matching items (rows).
For example: the expression:
will select those items which have the
error attribute set to "critical" and the
component attribute set to "PS1".
The query language supports the operators: + - * / ( ) ^ ! % == != < <= > >= ^= ^!= $= $!= << >> && || <> ><
These extension operators have the following meaning a ^= b a starts with the string b a ^!= b a does not start with the string b a $= b a ends with the string b a $!= b a does not end with the string b a >< b a contains the string b a <> b a does not contain the string b
Sub-expressions can be grouped with parenthesis and the boolean operators && and || can group conditional operands.
Regular expressions (delimited by slashes) may be used with the "==" and "!=" operators. The regular expression can be on either side of the operator.
The query language understands the types: Numbers, Boolean, String literals, Regular Expressions and null.
The Device Manager can display metric data via graphical widgets
You can select from the following widget types:
When creating or modifying a widget, you can select the data source to be either a database table item or a metric.
When selecting a metric, you enter the metric name, statistic and resource dimensions.
When selecting data directly from the database, you enter the database table model name, the model field (attribute) and a row selection expression.