# Opencensus.Honeycomb
[](https://circleci.com/gh/opencensus-beam/opencensus_honeycomb)
[](https://hex.pm/packages/opencensus_honeycomb)
Posts [OpenCensus] spans to [Honeycomb].
[OpenCensus]: https://opencensus.io
[Honeycomb]: https://www.honeycomb.io
## Installation
* Take the dependency
* Configure it
* Check its all working
### Dependency
Add `opencensus_honeycomb` to your `deps` in `mix.exs`:
```elixir
{:opencensus_honeycomb, "~> 0.1"}
```
Then, `mix deps.get` and `mix deps.compile` as usual.
### Configuration
In your `config/config.exs`, configure `:opencensus` and
`:opencensus_honeycomb`:
```eixir
config :opencensus,
reporters: [{Opencensus.Honeycomb.Reporter, []}],
send_interval_ms: 1000
config :opencensus_honeycomb,
dataset: "opencensus",
service_name: "your_app",
write_key: System.get_env("HONEYCOMB_WRITEKEY")
```
### Verification
`iex -S mix`, then:
iex> Application.get_env(:opencensus, :reporters)
[{Opencensus.Honeycomb.Reporter, []}]
iex> Application.get_all_env(:opencensus_honeycomb)
[write_key: "...", service_name: "...", dataset: "..."]
iex> :ocp.with_child_span("test")
:undefined
iex> :ocp.current_span_ctx()
{:span_ctx, 33234766236774033950150561980069751240,
12010566695198730064, 1, :undefined}
iex> :ocp.finish_span()
true
If you don't notice any sending, check the registration in case the config
format changed again. Register manually, then try again:
iex> :oc_reporter.register(Opencensus.Honeycomb.Reporter, [])
:ok
Once you've seen some spans, try a stack of ten:
iex> 1..10 |> Enum.map(&to_string/1) |> Enum.map(&:ocp.with_child_span/1)
[
:undefined,
{:span_ctx, 322560190005584483565962561333424343439,
7924041616779114111, 1, :undefined},
...
{:span_ctx, 322560190005584483565962561333424343439,
14682319351797855820, 1, :undefined},
]
iex> 1..10 |> Enum.map(fn _ -> :ocp.finish_span() end)
[true, true, true, true, true, true, true, true, true, true]
## Telemetry
Opencensus.Honeycomb calls `:telemetry.execute/2` before and after sending.
To get an idea without reading the in-code documentation, run the following
at the `iex -S mix` prompt:
```elixir
alias Opencensus.Honeycomb.{Config,Event,Sender}
Config.put(%{write_key: nil})
handle_event = fn n, measure, meta, _ -> IO.inspect({n, measure, meta}) end
:telemetry.attach_many("test", Sender.telemetry_events(), handle_event, nil)
[%Event{time: Event.now(), data: %{name: "hello"}}] |> Sender.send_batch()
```
You should see two events inspected:
```elixir
{[:opencensus, :honeycomb, :start], %{count: 1},
%{
events: [
# ...
]
}}
{[:opencensus, :honeycomb, :stop, :success], %{count: 1, ms: 5.535},
%{
events: [
# ...
],
payload: "..."
}}
```
Want to see that against the production API?
```elixir
Config.put(%{
write_key: System.get_env("HONEYCOMB_WRITEKEY"),
dataset: "smoketest"
})
[%Event{time: Event.now(), data: %{name: "hello"}}] |> Sender.send_batch()
```
## Development
Dependency management:
* `mix deps.get` to get your dependencies
* `mix deps.compile` to compile them
* `mix licenses` to check their license declarations, recursively
Finding problems:
* `mix compile` to compile your code
* `mix credo` to suggest more idiomatic style for it
* `mix dialyzer` to find problems static typing might spot... *slowly*
* `mix test` to run unit tests
* `mix test.watch` to run the tests again whenever you change something
* `mix coveralls` to check test coverage
Documentation:
* `mix docs` to generate documentation for this project
* `mix help` to find out what else you can do with `mix`
