Draft to change oteltest to use the sdk

[bogdandrutu]

Fixes #2072

Signed-off-by: Bogdan Drutu bogdandrutu@gmail.com

[bogdandrutu]

This PR is to prove how easily an oteltest package can be implemented on top of the SDK, and avoid 1000+ duplicate code lines.

[Aneurysm9]

This is the API module and MUST NOT depend on any SDK.

[bogdandrutu]

The API module probably MUST NOT depend on the oteltest :D

[bogdandrutu]

@Aneurysm9 if you resolve #2077 then this will go away :D

[MrAlias]

One of the intended purposes of the oteltest package is for it to be used by instrumentation authors to test their code. This means that it should not itself depend on the SDK as it will mean any use of it by the instrumentation authors would bring along that dependency. The approach taken here would violate this dependency requirement. Not only would this put a burden on our users to replace the oteltest package, but us as well:

• https://github.com/open-telemetry/opentelemetry-go-contrib/blob/262f81f753760cd1333d1925918300be3f01e77e/instrumentation/google.golang.org/grpc/otelgrpc/go.mod#L12
• https://github.com/open-telemetry/opentelemetry-go-contrib/blob/262f81f753760cd1333d1925918300be3f01e77e/instrumentation/go.mongodb.org/mongo-driver/mongo/otelmongo/go.mod#L12
• https://github.com/open-telemetry/opentelemetry-go-contrib/blob/262f81f753760cd1333d1925918300be3f01e77e/instrumentation/net/http/otelhttp/go.mod#L13
• https://github.com/open-telemetry/opentelemetry-go-contrib/blob/262f81f753760cd1333d1925918300be3f01e77e/instrumentation/net/http/httptrace/otelhttptrace/go.mod#L12
• https://github.com/open-telemetry/opentelemetry-go-contrib/blob/262f81f753760cd1333d1925918300be3f01e77e/instrumentation/github.com/aws/aws-sdk-go-v2/otelaws/go.mod#L17
• https://github.com/open-telemetry/opentelemetry-go-contrib/blob/262f81f753760cd1333d1925918300be3f01e77e/instrumentation/github.com/labstack/echo/otelecho/go.mod#L16
• https://github.com/open-telemetry/opentelemetry-go-contrib/blob/262f81f753760cd1333d1925918300be3f01e77e/instrumentation/github.com/go-kit/kit/otelkit/go.mod#L10
• https://github.com/open-telemetry/opentelemetry-go-contrib/blob/262f81f753760cd1333d1925918300be3f01e77e/instrumentation/github.com/bradfitz/gomemcache/memcache/otelmemcache/go.mod#L12
• https://github.com/open-telemetry/opentelemetry-go-contrib/blob/262f81f753760cd1333d1925918300be3f01e77e/instrumentation/github.com/gin-gonic/gin/otelgin/go.mod#L16
• https://github.com/open-telemetry/opentelemetry-go-contrib/blob/262f81f753760cd1333d1925918300be3f01e77e/instrumentation/github.com/gocql/gocql/otelgocql/go.mod#L14
• https://github.com/open-telemetry/opentelemetry-go-contrib/blob/262f81f753760cd1333d1925918300be3f01e77e/instrumentation/github.com/emicklei/go-restful/otelrestful/go.mod#L17
• https://github.com/open-telemetry/opentelemetry-go-contrib/blob/262f81f753760cd1333d1925918300be3f01e77e/instrumentation/github.com/Shopify/sarama/otelsarama/go.mod#L12
• https://github.com/open-telemetry/opentelemetry-go-contrib/blob/262f81f753760cd1333d1925918300be3f01e77e/instrumentation/github.com/gorilla/mux/otelmux/go.mod#L17
• https://github.com/open-telemetry/opentelemetry-go-contrib/blob/262f81f753760cd1333d1925918300be3f01e77e/instrumentation/github.com/astaxie/beego/otelbeego/go.mod#L18
• https://github.com/open-telemetry/opentelemetry-go-contrib/blob/262f81f753760cd1333d1925918300be3f01e77e/instrumentation/gopkg.in/macaron.v1/otelmacaron/go.mod#L15

That said, I think it is possible to unify and use the same implementation of a Tracer. It will need to be an implementation that the SDK would also take a dependency on. Meaning we could have an implementation in an internal package that both the sdk and oteltest would use.