max_metric_name_length
The `max_metric_name_length` directive sets the maximum allowable length for metric names in the NGINX WebAssembly module.
Description
The max_metric_name_length directive is crucial when defining metrics within the NGINX WebAssembly module, as it specifies the upper limit on the character count for metric names. This constraint helps ensure that metrics are well-formed and conform to expectations set by the underlying APIs that interact with the WebAssembly runtime. The directive's parameter is a single integer value that denotes the maximum length of the metric name. If defined properly, it safeguards against excessive lengths that might cause errors during metric registration or data collection.
When metrics are registered, the provided names will be compared to this length limitation to determine whether they are valid or if an error should be raised due to length violations. This functionality adheres to best practices for performance and maintainability by enforcing common naming conventions that are suitable for logging and monitoring purposes. Moreover, incorrectly configured metric lengths can lead to configuration errors or runtime exceptions, so using this directive properly helps maintain smooth operation in environments leveraging the Proxy-Wasm module.
Config Example
wasm {
max_metric_name_length 256;
module my_metrics /path/to/metrics_module.wasm;
}Using a metric name that exceeds the defined length will result in a registration error.
Ensure that all metric names adhere to the specified length to avoid runtime errors during metric collection.