| context | Package context defines the Context type, which carries deadlines, cancellation signals, and other request-scoped values across API boundaries and between processes. |
| encoding/base64 | Package base64 implements base64 encoding as specified by RFC 4648. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| github.com/grpc-ecosystem/go-grpc-middleware | `grpc_middleware` is a collection of gRPC middleware packages: interceptors, helpers and tools. |
| github.com/grpc-ecosystem/go-grpc-middleware/tags | `grpc_ctxtags` adds a Tag object to the context that can be used by other middleware to add context about a request. |
| github.com/grpc-ecosystem/go-grpc-middleware/util/metautils | |
| github.com/opentracing/opentracing-go | |
| github.com/opentracing/opentracing-go/ext | |
| github.com/opentracing/opentracing-go/log | |
| golang.org/x/net/context | Package context defines the Context type, which carries deadlines, cancellation signals, and other request-scoped values across API boundaries and between processes. |
| google.golang.org/grpc | Package grpc implements an RPC system called gRPC. |
| google.golang.org/grpc/grpclog | Package grpclog defines logging for grpc. |
| google.golang.org/grpc/metadata | Package metadata define the structure of the metadata supported by gRPC library. |
| io | Package io provides basic interfaces to I/O primitives. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |
| sync | Package sync provides basic synchronization primitives such as mutual exclusion locks. |