Charts with Code

You can also create charts using Python, just as you would your features and resolvers.

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Charts and Series

The heart of the Chart paradigm is the Series, a single collection of data points over time. They must be instantiated with a metric and name, and can accumulate filters and group-bys to support advanced calculations. Some Series metrics require a window function parameter to decide how to calculate values. Window functions often include aggregates such as count and mean and percentiles such as 95% and 99%. Methods and options will auto-complete in your text editor based on the type of series.

Series objects must be attached to a Chart, which can have multiple series and up to one trigger.

from chalk.monitoring import Chart, Series

Chart(
    name="my_chart_1",
    window_period="30m"
).with_series(
    Series.resolver_latency_metric(
        name="p95 latency for `get_fraud_profile`",
        window_function="95%"
    ).where(resolver=get_fraud_profile)
)

This is all that’s necessary to ship a chart to your online dashboard upon chalk apply!

Using this builder pattern, we’re able to generate charts quickly and by reusing intermediate instances if necessary since every instance is deep-copied from the previous instance.

By default, only non-copied charts will be registered to the server. Consider the following example:

from chalk.monitoring import Chart, Series

base = Chart(
    name="my_chart_1",
    window_period="30m",
).with_series(
    Series.resolver_latency_metric(
        name="p99",
        window_function="99%",
    )
)

modified = base.with_series(
    Series.resolver_latency_metric(
        name="p99",
        window_function="99%",
    ).where(resolver_type='online')
)

Since modified has not been copied, it will be the only one of the three to be shipped to the server. However, base has been copied, and will not create a chart. To force-register charts to the server, use .keep(), which will be applied to the chart itself and all its descendants.

In the above example, we also added a filter to our Series object. Here, we restrict the series to only calculate latencies for online resolvers. The filters enabled differ depending on the series metric, and the appropriate options should be available through auto-complete in your text editor.

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Triggers

Triggers can also be added to charts. The following error trigger will alert myemail@chalk.ai when the resolver get_fraud_profile takes more than 200ms to execute.

from chalk.monitoring import Chart, Series

p95_latency = Series.resolver_latency_metric(
    name="p95 latency",
    window_function="95%",
).where(resolver=get_fraud_profile)
Chart(name="my_chart_1", window_period="30m").with_series(
    p95_latency
).with_trigger(
    p95_latency > 0.2,
    trigger_name=f"High latency alert",
    severity="error",
    channel_name="myemail@chalk.ai",
)

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Advanced Chart Building

We can also easily create charts in bulk. Let’s say we have a feature class Transaction with four scalar features.

from chalk.monitoring import Chart, Series

for feature in Transaction:
    request_series = Series.feature_request_count_metric(
        name=f"{feature} request count chart",
    ).where(feature=feature)

    Chart(
        name=f"{feature} request count chart",
        window_period="5m"
    ).with_series(request_series).with_trigger(
        request_series < 10,
        trigger_name=f"Low volume requests for {feature}",
        severity="error",
        channel_name="myemail@chalk.ai",
    )

Upon chalk apply, four charts will be registered to the server filtering on feature requests for each of the four features!