Add safetyTags property to tracer exporters

[icebob]

📝 Description

Option 1

A common problem is that developers or external modules send non-serializable parameters (e.g. http request, socket instance, stream instance...etc) in ctx.params or ctx.meta. If tracing is enabled, the tracer exporters try to convert these parameters in flattenTags methods which is flattening the given object recursively, which causes maximum call stack error.

To avoid it, we added a safetyTags option to the exporter options. If it is true, the exporters remove the cyclic properties before flattening the tags in the spans. This option is available in all built-in exporters.

Please note, this enabled option affects the performance, this is the reason why it's not enabled by default.

// moleculer.config.js
{
    tracing: {
        exporter: [{
            type: "Zipkin",
            options: {
                safetyTags: true,
                baseURL: "http://127.0.0.1:9411"
            }
        }]
    }
}

Option 2

To avoid that all action span tags will be converted because only just a few are affected by the problem, you can enable this function at action-level as well.

broker.createService({
    name: "greeter",
    actions: {
        hello: {
            tracing: {
                safetyTags: true
            },
            handler(ctx) {
                return `Hello!`;
            }
        }
    }
});

🎯 Relevant issues

Resolves #777, #908

💎 Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

[ghost]

CodeSee Review Map:

Review in an interactive map

View more CodeSee Maps

Legend