launchdarkly_server_sdk

# Change log

All notable changes to the LaunchDarkly Erlang/Elixir SDK will be documented in this file. This project adheres to [Semantic Versioning](http://semver.org).

## [1.3.2] - 2021-12-30
### Fixed:
- The file `file_auto_update` feature was not working correctly. If the flag files did not contain any changes between polling intervals, then the file system watcher would crash. (Thanks, [matt-glover](https://github.com/launchdarkly/erlang-server-sdk/pull/52)!)

## [1.3.1] - 2021-11-09
### Fixed:
- Updated the `options()` typings for `ldclient_instance:start` to include missing configuration options. These included redis configuration, ld relay configuration, cache ttl, file data source configuration, and the http options. This is not a functionality change, but will correct issues reported by the dialyzer.

## [1.3.0] - 2021-11-03
### Added:
- Support for configuring HTTP options. Including:
     - The ability to specify custom headers.

     ```
      ldclient_config:parse_options("sdk-key", #{
        http_options => #{
            custom_headers => [
                {"Basic-String-Header", "String"},
                {"Binary-String-Header", "Binary"}
            ]}
        }),
    ```
    - The ability to specify a custom connect timeout.
 
    ```
    ldclient_config:parse_options("sdk-key", #{
        http_options => #{
            connect_timeout => 2000
        }
    }),
    ```
    - The ability to specify a custom TLS configuration.
    The default behavior for OTP is to use `verify_none` for TLS verification. If no configuration is specified, then the SDK will inherit this behavior.

    ```
    ldclient_config:parse_options("sdk-key", #{
        http_options => #{
            %% This is a list of tls_client_options()
            %% https://www.erlang.org/doc/man/ssl.html#type-tls_client_option
            tls_options => ldclient_config:tls_basic_options()
        }
    }),
    ```
    - A number of TLS configuration helpers. A full TLS configuration can be specified, but these methods provide a number of basic configurations.
        - `ldclient_config:tls_basic_options() -> [ssl:tls_client_option()]`  
        Create a basic TLS configuration which will try to use a default location for certificate authority store.
        If that store is not present, then instead the configuration will use a certifi store which is a Rebar3 dependency.
        - `ldclient_config:tls_basic_linux_options() -> [ssl:tls_client_option()]`
        Create a basic TLS configuration which will use a default location for a certificate store. If the store is not present, then it will produce an error.
        - `ldclient_config:tls_ca_certfile_options(CaStorePath :: string()) -> [ssl:tls_client_option()]`
        Create a basic TLS configuration with the specified certificate store. If the store is not present, then it will produce an error.
        - `ldclient_config:with_tls_revocation(Options :: [ssl:tls_client_option()]) -> [ssl:tls_client_option()]`
        Decorate a configuration with revocation checks. Currently revocation checks are not cached in OTP, so this will result in additional requests for each HTTP request.
        - `ldclient_config:tls_basic_certifi_options() -> [ssl:tls_client_option()]`
        Create a basic TLS configuration which will use the certifi store specified in the Rebar3 dependencies.

## [1.2.0] - 2021-10-18
### Added:
- The SDK now supports the ability to control the proportion of traffic allocation to an experiment. This works in conjunction with a new platform feature now available to early access customers.
- The SDK now supports the ability to read flags from a file.

## [1.1.3] - 2021-09-27
### Fixed:
- When a rule was missing both the rollout and the variation, and that rule was matched, then variation 0 would be returned instead of the default value.
- When a fall-through was missing both a rollout and a variation, then null would be returned instead of the default value.

## [1.1.2] - 2021-09-13
### Fixed:
- The SDK now forces connections to use HTTP/1.1 instead of the newer HTTP/2 protocol as an underlying dependency does not yet support HTTP/2. This change does not impact current behavior as LaunchDarkly’s servers do not yet accept requests with HTTP/2; however, this SDK change ensures operational continuity when LaunchDarkly’s services enable HTTP/2 compatibility.
- The SDK is more resilient when opening an SSE connection, processing events from the stream, and evaluating feature flags.

## [1.1.1] - 2021-08-06
### Changed:
- Updated the `eredis` dependency to version `1.4.0`. (Thanks, [jeffgrunewald](https://github.com/launchdarkly/erlang-server-sdk/pull/32)!)
- Updated the `jsx` dependency to version `3.1.0`. (Thanks, [bitwalker](https://github.com/launchdarkly/erlang-server-sdk/pull/35)!)
- Updated the `uuid` dependency to version `2.0.2`. (Thanks, [jeffgrunewald](https://github.com/launchdarkly/erlang-server-sdk/pull/32)!)
- Expanded test coverage to include OTP 24.

## [1.1.0] - 2021-05-06
### Added:
- `ldclient:alias/2` and `ldclient:alias/3` functions. These can be used to associate two user objects for analytics purposes with an alias event.


## [1.0.1] - 2021-02-23
### Changed:
- Removed internal storage files from generated documentation.




## [1.0.0] - 2021-02-22
Initial supported release of the SDK.

### Added:
- Added Redis feature store.
- Added LDD mode.
- Reload in-memory flag data when storage server fails.

### Changed:
- Parse flags and segments before in-memory storage.
- Updated the default base URL to `sdk.launchdarkly.com`.
- Events URL path from `api/events/bulk` to `/bulk`.
- Renamed `ldclient_settings` to `ldclient_config`.
- Renamed `ldclient:track_with_metric` to `ldclient:track_metric`.
- Improved generated documentation.

### Fixed:
- Ignore path in streaming put events.

### Removed:
- Removed `ldclient_settings`.
- Removed `ldclient:track_with_metric`.



## [1.0.0-beta4] - 2020-08-27

### Changed

- Updaters now initialize asynchronously.
- Updated `shotgun` from 0.4.0 to 0.5.0.

### Fixed

- Fixed `GenServer` crash on socket close in `handle_cast` in `ldclient_event_dispatch_httpc.erl`.
- Fixed network timeout on initial connection.
- Fixed restarting updates after a crash.
- Fixed updater initialization state bugs.

## [1.0.0-beta3] - 2020-05-18

### Added

- Added Erlang/OTP 23 image to CircleCI tests

### Fixed

- Fixed a bug preventing user first name and last name attibutes from properly being set
- Fixed dates in tests to be RFC3339 compliant
- Fixed dialyzer warning when application was started with `offline` option
- Fixed SSE parsing bug in shotgun library with a workaround

## [1.0.0-beta2] - 2020-02-20

### Changed

- Renamed `eld` to `ldclient` to better adhere to LaunchDarkly SDK naming conventions.
- Changed the `pkg_name` to `launchdarkly_server_sdk`

## [1.0.0-beta1] - 2020-02-12

### Added

- Added offline mode which stops the SDK making remote calls to LaunchDarkly and variation calls will then fall back to default values for your feature flags. You can do this by setting offline mode in the config map with the `offline` key.

- Added ETag polling cache for If-None-Match on update requests.

- The SDK now specifies a uniquely identifiable request header when sending events to LaunchDarkly to ensure that events are only processed once, even if the SDK sends them two times due to a failed initial attempt.

- Added an initialized function which indicates whether the SDK is in offline mode or if the update processor has been initialized.

### Changed

- Return last variation when user bucket exceeds variation weight sum.

- Client now checks initialization status when evaluating a variation or all flags.

## [1.0.0-alpha4] - 2019-12-19

### Added

- Support for experimentation features. See `eld:track_with_metric/4-5`.

### Fixed

- Custom URI configuration is now consistent with other SDKs
- Bucketing logic for custom non-string attributes is brought in line with the other SDKs

## [1.0.0-alpha3] - 2019-10-29

### Fixed

- Dependencies specify tagged versions and use hex (thank you @hez)
- `eld:all_flags_state/2` now uses correct non-default instance (thank you @hez)
- Streaming connection will now retry after initial request timeout

### Removed
- `eld:evaluate/3-4` which were deprecated in the previous version
- `erlang.mk`, `Makefile` now uses `rebar3`

## [1.0.0-alpha2] - 2019-08-07

### Added

- Support for all server side LaunchDarkly events
- `eld:variation/3-4` and `eld:variation_detail/3-4` functions to replace `eld:evaluate/3-4` to reflect the naming convention
- Feature to inline users inside events
- Feature to define global private user attributes, including making all user attributes private

### Fixed

- Events POST URI, it no longer gets HTTP 405 Method Not Allowed error

### Deprecated
- `eld:evaluate/3-4` will be removed in a future release

### Missing

- Polling support
- Known issues for some edge case error conditions, and other minor missing features

## [1.0.0-alpha1] - 2019-07-24

### Added

- Initial public release
- Support for streaming and evaluations

### Missing

- Events don't pass integration tests
- Polling support
- Other known issues and minor missing features