feat: ofrep provider (#53)

Signed-off-by: Rahul Baradol <[email protected]>

Author: Rahul-Baradol

Cargo.toml

@@ -12,5 +12,6 @@ edition = "2021"
 members = [
     "crates/env-var",
     "crates/flagd",
-    "crates/flipt"
-]
+    "crates/flipt",
+    "crates/ofrep"
+]

crates/ofrep/Cargo.toml

@@ -0,0 +1,26 @@
+[package]
+name = "open-feature-ofrep"
+version = "0.0.1"
+edition = "2024"
+
+[dev-dependencies]
+wiremock = "0.6.3"
+test-log = { version = "0.2", features = ["trace"] }
+serial_test = "3.2.0"
+
+[dependencies]
+async-trait = "0.1.88"
+open-feature = "0.2.5"
+reqwest = { version = "0.12", default-features = false, features = [
+  "json",
+  "stream",
+  "rustls-tls",
+] }
+serde_json = "1.0.140"
+tracing = "0.1.41"
+thiserror = "2.0"
+anyhow = "1.0.98"
+chrono = "0.4"
+once_cell = "1.18"
+tokio = { version = "1.45", features = ["full"] }
+url = "2.5.4"

crates/ofrep/README.md

@@ -0,0 +1,56 @@
+[Generated by cargo-readme: `cargo readme --no-title --no-license > README.md`]::
+ # OFREP Provider for OpenFeature
+
+A Rust implementation of the OpenFeature OFREP provider, enabling dynamic
+feature flag evaluation in your applications.
+
+This provider allows to connect to any feature flag management system that supports OFREP.
+
+### Installation
+Add the dependency in your `Cargo.toml`:
+```bash
+cargo add open-feature-ofrep
+cargo add open-feature
+```
+Then integrate it into your application:
+
+```rust
+use std::time::Duration;
+use open_feature::provider::FeatureProvider;
+use open_feature::EvaluationContext;
+use open_feature_ofrep::{OfrepProvider, OfrepOptions};
+use reqwest::header::{HeaderMap, HeaderValue};
+
+#[tokio::main]
+async fn main() {
+    let mut headers = HeaderMap::new();
+    headers.insert("color", HeaderValue::from_static("yellow"));
+
+    let provider = OfrepProvider::new(OfrepOptions {
+        base_url: "http://localhost:8016".to_string(),
+        headers: headers.clone(),
+        connect_timeout: Duration::from_secs(4), 
+        ..Default::default()
+    }).await.unwrap();
+
+    let context = EvaluationContext::default()
+                    .with_targeting_key("user-123")
+                    .with_custom_field("color", "yellow");
+
+    let result = provider.resolve_bool_value("isColorYellow", &context).await.unwrap();
+    println!("Flag value: {}", result.value);
+}
+```
+
+### Configuration Options
+Configurations can be provided as constructor options. The following options are supported:
+
+| Option                                  | Type / Supported Value            | Default                             |
+|-----------------------------------------|-----------------------------------|-------------------------------------|
+| base_url                                | string                            | http://localhost:8016               |
+| headers                                 | HeaderMap                         | Empty Map                           |
+| connect_timeout                         | Duration                          | 10 seconds                          |
+
+### License
+Apache 2.0 - See [LICENSE](./../../LICENSE) for more information.
+

crates/ofrep/src/error.rs

@@ -0,0 +1,30 @@
+use thiserror::Error;
+
+#[derive(Error, Debug, PartialEq)]
+pub enum OfrepError {
+    #[error("Provider error: {0}")]
+    Provider(String),
+    #[error("Connection error: {0}")]
+    Connection(String),
+    #[error("Invalid configuration: {0}")]
+    Config(String),
+}
+
+// Add implementations for error conversion
+impl From<Box<dyn std::error::Error>> for OfrepError {
+    fn from(error: Box<dyn std::error::Error>) -> Self {
+        OfrepError::Provider(error.to_string())
+    }
+}
+
+impl From<Box<dyn std::error::Error + Send + Sync>> for OfrepError {
+    fn from(error: Box<dyn std::error::Error + Send + Sync>) -> Self {
+        OfrepError::Provider(error.to_string())
+    }
+}
+
+impl From<anyhow::Error> for OfrepError {
+    fn from(error: anyhow::Error) -> Self {
+        OfrepError::Provider(error.to_string())
+    }
+}

crates/ofrep/src/lib.rs

@@ -0,0 +1,150 @@
+mod error;
+mod resolver;
+
+use error::OfrepError;
+use open_feature::provider::{FeatureProvider, ProviderMetadata, ResolutionDetails};
+use open_feature::{EvaluationContext, EvaluationError, StructValue};
+use reqwest::header::HeaderMap;
+use resolver::Resolver;
+use std::fmt;
+use std::sync::Arc;
+use std::time::Duration;
+use tracing::debug;
+use tracing::instrument;
+use url::Url;
+
+use async_trait::async_trait;
+
+const DEFAULT_BASE_URL: &str = "http://localhost:8016";
+const DEFAULT_CONNECT_TIMEOUT: Duration = Duration::from_secs(10);
+
+#[derive(Debug, Clone)]
+pub struct OfrepOptions {
+    pub base_url: String,
+    pub headers: HeaderMap,
+    pub connect_timeout: Duration,
+}
+
+impl Default for OfrepOptions {
+    fn default() -> Self {
+        OfrepOptions {
+            base_url: DEFAULT_BASE_URL.to_string(),
+            headers: HeaderMap::new(),
+            connect_timeout: DEFAULT_CONNECT_TIMEOUT,
+        }
+    }
+}
+
+pub struct OfrepProvider {
+    provider: Arc<dyn FeatureProvider + Send + Sync>,
+}
+
+impl fmt::Debug for OfrepProvider {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("OfrepProvider")
+            .field("provider", &"<FeatureProvider>")
+            .finish()
+    }
+}
+
+impl OfrepProvider {
+    #[instrument(skip(options))]
+    pub async fn new(options: OfrepOptions) -> Result<Self, OfrepError> {
+        debug!("Initializing OfrepProvider with options: {:?}", options);
+
+        let url = Url::parse(&options.base_url).map_err(|e| {
+            OfrepError::Config(format!("Invalid base url: '{}' ({})", options.base_url, e))
+        })?;
+
+        if !matches!(url.scheme(), "http" | "https") {
+            return Err(OfrepError::Config(format!(
+                "Invalid base url: '{}' (unsupported scheme)",
+                url.scheme()
+            )));
+        }
+
+        Ok(Self {
+            provider: Arc::new(Resolver::new(&options)),
+        })
+    }
+}
+
+#[async_trait]
+impl FeatureProvider for OfrepProvider {
+    fn metadata(&self) -> &ProviderMetadata {
+        self.provider.metadata()
+    }
+
+    async fn resolve_bool_value(
+        &self,
+        flag_key: &str,
+        context: &EvaluationContext,
+    ) -> Result<ResolutionDetails<bool>, EvaluationError> {
+        self.provider.resolve_bool_value(flag_key, context).await
+    }
+
+    async fn resolve_int_value(
+        &self,
+        flag_key: &str,
+        context: &EvaluationContext,
+    ) -> Result<ResolutionDetails<i64>, EvaluationError> {
+        self.provider.resolve_int_value(flag_key, context).await
+    }
+
+    async fn resolve_float_value(
+        &self,
+        flag_key: &str,
+        context: &EvaluationContext,
+    ) -> Result<ResolutionDetails<f64>, EvaluationError> {
+        self.provider.resolve_float_value(flag_key, context).await
+    }
+
+    async fn resolve_string_value(
+        &self,
+        flag_key: &str,
+        context: &EvaluationContext,
+    ) -> Result<ResolutionDetails<String>, EvaluationError> {
+        self.provider.resolve_string_value(flag_key, context).await
+    }
+
+    async fn resolve_struct_value(
+        &self,
+        flag_key: &str,
+        context: &EvaluationContext,
+    ) -> Result<ResolutionDetails<StructValue>, EvaluationError> {
+        self.provider.resolve_struct_value(flag_key, context).await
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use test_log::test;
+
+    #[test(tokio::test)]
+    async fn test_ofrep_options_validation() {
+        let provider_with_empty_host = OfrepProvider::new(OfrepOptions {
+            base_url: "http://".to_string(),
+            ..Default::default()
+        })
+        .await;
+
+        let provider_with_invalid_scheme = OfrepProvider::new(OfrepOptions {
+            base_url: "invalid://".to_string(),
+            ..Default::default()
+        })
+        .await;
+
+        assert!(provider_with_empty_host.is_err());
+        assert!(provider_with_invalid_scheme.is_err());
+
+        assert_eq!(
+            provider_with_empty_host.unwrap_err(),
+            OfrepError::Config("Invalid base url: 'http://' (empty host)".to_string())
+        );
+        assert_eq!(
+            provider_with_invalid_scheme.unwrap_err(),
+            OfrepError::Config("Invalid base url: 'invalid' (unsupported scheme)".to_string())
+        );
+    }
+}