Get Data Samples from Go services¶
To get Data Samples
from your Go services, you can use the sampler
module which is provided as part of the Neblic platform code. Since Go is the primary language used by Neblic to implement its components, this library acts as the reference implementation of the Neblic Control Plane
protocol, so it will always implement the latest features.
Usage¶
Note
All code snippets have error handling omitted for brevity
To add Samplers
in your code that export Data Samples
you first need to initialize a Provider
. A Provider
receives a configuration that is then used to configure and initialize all the Samplers
in your application.
import (
"context"
"github.com/neblic/platform/logging"
"github.com/neblic/platform/sampler"
"github.com/neblic/platform/sampler/defs"
"github.com/neblic/platform/sampler/global"
)
func initProvider() defs.Provider {
// the `Settings` struct contains the required configuration settings
settings := sampler.Settings{
ResourceName: "service-name",
ControlServerAddr: "otelcol:8899",
DataServerAddr: "otelcol:4317",
}
// additional options are provided with the `Options Pattern`
logger, _ := logging.NewZapDev()
provider, _ := sampler.NewProvider(context.Background(), settings, sampler.WithLogger(logger))
// optional: It is recommended to register the `Provider` as global.
// this will allow you to initialize a `Sampler` from anywhere in your code
// without needing a reference to the `Provider`.
global.SetSamplerProvider(provider)
return provider
}
To see details about the required settings and available options, see this page.
Once the Provider
is initialized, you can use it to initialize Samplers
. If you have registered the provider as global, you can simply call the Sampler
method from anywhere in your application. If not, you will need to call the Sampler
method of your provider. They both have the same signature so the following explanation works for both options.
Info
It is not required to first initialize and register the Provider
as global before creating Samplers
. If a Sampler
is initialized using the global provider before a Provider
is registered, it will return a stubbed Sampler
with no-op methods. Once the Provider
is registered, it will internally replace the no-op stub with the real Sampler
. This happens transparently for the application.
import (
"github.com/neblic/platform/sampler"
"github.com/neblic/platform/sampler/defs"
)
func initSampler() defs.Sampler {
// initialize the schema that the sampled `Data Samples` will
// a `DynamicSchema` supports Json strings and Go structs
schema := defs.NewDynamicSchema()
// equivalent to calling `global.SamplerProvider().Sampler()`
someSampler, _ := sampler.Sampler("sampler-name", schema)
return someSampler
}
To see what other schemas the Go Sampler supports, check this Godoc page.
Once you have initialized the Sampler
, you can call any of its methods to have it evaluate a Data Sample
. It will then be evaluated by any configured Sampling Rule
and exported if there is a match.
Warning
You need to be mindful of what methods you use to sample data. Depending on the schema provided when the Sampler
is initialized, some methods will work better or faster than others.
As a rule of thumb, you want to provide a schema if you have it since this allows the Sampler
to internally optimize how it evaluates the Sampling Rules
. If you do not have it, a sampler configured with a DynamicSchema
is capable of processing any type data using any of the sampling methods. See the Godoc documentation for details.
func sampleData(ctx context.Context) bool {
var dataSample string
// evaluate a `Data Sample`
sampled, _ := someSampler.SampleJSON(ctx, dataSample)
return sampled
}
In this example, since the Sampler
was initialized with a DynamicSchema
, it is best to use the method SampleJson()
or SampleNative()
. These sampling methods are designed to work with samples that do not have a fixed or known schema.
gRPC interceptor¶
If you use gRPC servers or clients in your services, you can make use of a gRPC interceptor. They will automatically create Samplers
that will efficiently intercept all requests and responses.
Internally, they create Samplers
with a ProtoSchema
so they do not need to deserialize the Protobuf
message to evaluate its contents.
To use it, you need to initialize the interceptor and provide it when initializing the gRPC connection
import (
"context"
neblicgrpc "github.com/neblic/platform/sampler/instrumentation/google.golang.org/grpc"
"google.golang.org/grpc"
)
func initInterceptor() *grpc.ClientConn {
interceptor := neblicgrpc.UnaryClientInterceptor()
conn, _ := grpc.DialContext(context.Background(), "server-addr:port",
grpc.WithUnaryInterceptor(interceptor))
return conn
}
Documentation¶
Check the Godoc documentation to see the sampler
module documentation.