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Programming

In this section, we will discuss the general steps of building a program on top of the Hermes native API. We will focus on the core data structures provided by Hermes -- Buckets and Blobs.

To see demonstrations of the API, check out our API tests

Basic API Example​

This example will place a blob into the DMSH and then retrieve that blob.

#include <hermes.h>
#include <bucket.h>

int main() {
  TRANSPARENT_HERMES();
  Bucket bkt = HERMES->GetBucket("hello");
  size_t blob_size = KILOBYTES(4);
  Context ctx;

  std::vector<int> data_put(1024, i);
  bkt.Put<std::vector<int>>("0", data_put, ctx);

  std::vector<int> data_get(1024, i);
  bkt.Get<std::vector<int>>("0", data_get, ctx);

  REQUIRE(data_put == data_get);
}
  • TRANSPARENT_HERMES() will initialize your connection to Hermes
  • HERMES is a singleton macro provided in hermes.h.
  • GetBucket will either create a bucket or get the bucket if it exists. This operation is concurrency-safe. I.e., it is guaranteed only one thread or process calling this function will create the bucket if it DNE.
  • Context is optional. It contains the ability to override defaults defined in the server and client configuration files. For example, you can set a custom DPE to use for a blob Put.
  • hermes::Blob analagous to and std::vector<char>. It's not quite the same thing, but we won't go into detail here.
  • bkt.Put will put a blob into the bucket. Put replaces all content if the blob previously existed.
  • bkt.Get will get the contents of an entire blob.