feat(flags): Extract flag definitions from redis (#42)

Author: neilkakkar

feature-flags/src/flag_definitions.rs

@@ -0,0 +1,200 @@
+use serde::{Deserialize, Serialize};
+use std::sync::Arc;
+use tracing::instrument;
+
+use crate::{
+    api::FlagError,
+    redis::{Client, CustomRedisError},
+};
+
+// TRICKY: This cache data is coming from django-redis. If it ever goes out of sync, we'll bork.
+// TODO: Add integration tests across repos to ensure this doesn't happen.
+pub const TEAM_FLAGS_CACHE_PREFIX: &str = "posthog:1:team_feature_flags_";
+
+// TODO: Hmm, revisit when dealing with groups, but seems like
+// ideal to just treat it as a u8 and do our own validation on top
+#[derive(Debug, Deserialize, Serialize)]
+pub enum GroupTypeIndex {}
+
+#[derive(Debug, Deserialize, Serialize)]
+pub enum OperatorType {
+    #[serde(rename = "exact")]
+    Exact,
+    #[serde(rename = "is_not")]
+    IsNot,
+    #[serde(rename = "icontains")]
+    Icontains,
+    #[serde(rename = "not_icontains")]
+    NotIcontains,
+    #[serde(rename = "regex")]
+    Regex,
+    #[serde(rename = "not_regex")]
+    NotRegex,
+    #[serde(rename = "gt")]
+    Gt,
+    #[serde(rename = "lt")]
+    Lt,
+    #[serde(rename = "gte")]
+    Gte,
+    #[serde(rename = "lte")]
+    Lte,
+    #[serde(rename = "is_set")]
+    IsSet,
+    #[serde(rename = "is_not_set")]
+    IsNotSet,
+    #[serde(rename = "is_date_exact")]
+    IsDateExact,
+    #[serde(rename = "is_date_after")]
+    IsDateAfter,
+    #[serde(rename = "is_date_before")]
+    IsDateBefore,
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+pub struct PropertyFilter {
+    pub key: String,
+    pub value: serde_json::Value,
+    pub operator: Option<OperatorType>,
+    #[serde(rename = "type")]
+    pub prop_type: String,
+    pub group_type_index: Option<u8>,
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+pub struct FlagGroupType {
+    pub properties: Option<Vec<PropertyFilter>>,
+    pub rollout_percentage: Option<f32>,
+    pub variant: Option<String>,
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+pub struct MultivariateFlagVariant {
+    pub key: String,
+    pub name: Option<String>,
+    pub rollout_percentage: f32,
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+pub struct MultivariateFlagOptions {
+    pub variants: Vec<MultivariateFlagVariant>,
+}
+
+// TODO: test name with https://www.fileformat.info/info/charset/UTF-16/list.htm values, like '𝖕𝖗𝖔𝖕𝖊𝖗𝖙𝖞': `𝓿𝓪𝓵𝓾𝓮`
+
+#[derive(Debug, Deserialize, Serialize)]
+pub struct FlagFilters {
+    pub groups: Vec<FlagGroupType>,
+    pub multivariate: Option<MultivariateFlagOptions>,
+    pub aggregation_group_type_index: Option<u8>,
+    pub payloads: Option<serde_json::Value>,
+    pub super_groups: Option<Vec<FlagGroupType>>,
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+pub struct FeatureFlag {
+    pub id: i64,
+    pub team_id: i64,
+    pub name: Option<String>,
+    pub key: String,
+    pub filters: FlagFilters,
+    #[serde(default)]
+    pub deleted: bool,
+    #[serde(default)]
+    pub active: bool,
+    #[serde(default)]
+    pub ensure_experience_continuity: bool,
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+
+pub struct FeatureFlagList {
+    pub flags: Vec<FeatureFlag>,
+}
+
+impl FeatureFlagList {
+    /// Returns feature flags given a team_id
+
+    #[instrument(skip_all)]
+    pub async fn from_redis(
+        client: Arc<dyn Client + Send + Sync>,
+        team_id: i64,
+    ) -> Result<FeatureFlagList, FlagError> {
+        // TODO: Instead of failing here, i.e. if not in redis, fallback to pg
+        let serialized_flags = client
+            .get(format!("{TEAM_FLAGS_CACHE_PREFIX}{}", team_id))
+            .await
+            .map_err(|e| match e {
+                CustomRedisError::NotFound => FlagError::TokenValidationError,
+                CustomRedisError::PickleError(_) => {
+                    tracing::error!("failed to fetch data: {}", e);
+                    println!("failed to fetch data: {}", e);
+                    FlagError::DataParsingError
+                }
+                _ => {
+                    tracing::error!("Unknown redis error: {}", e);
+                    FlagError::RedisUnavailable
+                }
+            })?;
+
+        let flags_list: Vec<FeatureFlag> =
+            serde_json::from_str(&serialized_flags).map_err(|e| {
+                tracing::error!("failed to parse data to flags list: {}", e);
+                println!("failed to parse data: {}", e);
+
+                FlagError::DataParsingError
+            })?;
+
+        Ok(FeatureFlagList { flags: flags_list })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use rand::Rng;
+
+    use super::*;
+    use crate::test_utils::{
+        insert_flags_for_team_in_redis, insert_new_team_in_redis, setup_redis_client,
+    };
+
+    #[tokio::test]
+    async fn test_fetch_flags_from_redis() {
+        let client = setup_redis_client(None);
+
+        let team = insert_new_team_in_redis(client.clone()).await.unwrap();
+
+        insert_flags_for_team_in_redis(client.clone(), team.id, None)
+            .await
+            .expect("Failed to insert flags");
+
+        let flags_from_redis = FeatureFlagList::from_redis(client.clone(), team.id)
+            .await
+            .unwrap();
+        assert_eq!(flags_from_redis.flags.len(), 1);
+        let flag = flags_from_redis.flags.get(0).unwrap();
+        assert_eq!(flag.key, "flag1");
+        assert_eq!(flag.team_id, team.id);
+        assert_eq!(flag.filters.groups.len(), 1);
+        assert_eq!(flag.filters.groups[0].properties.as_ref().unwrap().len(), 1);
+    }
+
+    #[tokio::test]
+    async fn test_fetch_invalid_team_from_redis() {
+        let client = setup_redis_client(None);
+
+        match FeatureFlagList::from_redis(client.clone(), 1234).await {
+            Err(FlagError::TokenValidationError) => (),
+            _ => panic!("Expected TokenValidationError"),
+        };
+    }
+
+    #[tokio::test]
+    async fn test_cant_connect_to_redis_error_is_not_token_validation_error() {
+        let client = setup_redis_client(Some("redis://localhost:1111/".to_string()));
+
+        match FeatureFlagList::from_redis(client.clone(), 1234).await {
+            Err(FlagError::RedisUnavailable) => (),
+            _ => panic!("Expected RedisUnavailable"),
+        };
+    }
+}

feature-flags/src/lib.rs

@@ -1,5 +1,6 @@
 pub mod api;
 pub mod config;
+pub mod flag_definitions;
 pub mod redis;
 pub mod router;
 pub mod server;

feature-flags/src/test_utils.rs

@@ -1,7 +1,9 @@
 use anyhow::Error;
+use serde_json::json;
 use std::sync::Arc;
 
 use crate::{
+    flag_definitions,
     redis::{Client, RedisClient},
     team::{self, Team},
 };
@@ -40,6 +42,47 @@ pub async fn insert_new_team_in_redis(client: Arc<RedisClient>) -> Result<Team,
     Ok(team)
 }
 
+pub async fn insert_flags_for_team_in_redis(
+    client: Arc<RedisClient>,
+    team_id: i64,
+    json_value: Option<String>,
+) -> Result<(), Error> {
+    let payload = match json_value {
+        Some(value) => value,
+        None => json!([{
+            "id": 1,
+            "key": "flag1",
+            "name": "flag1 description",
+            "active": true,
+            "deleted": false,
+            "team_id": team_id,
+            "filters": {
+                "groups": [
+                    {
+                        "properties": [
+                            {
+                                "key": "email",
+                                "value": "[email protected]",
+                                "type": "person",
+                            },
+                        ]
+                    },
+                ],
+            },
+        }])
+        .to_string(),
+    };
+
+    client
+        .set(
+            format!("{}{}", flag_definitions::TEAM_FLAGS_CACHE_PREFIX, team_id),
+            payload,
+        )
+        .await?;
+
+    Ok(())
+}
+
 pub fn setup_redis_client(url: Option<String>) -> Arc<RedisClient> {
     let redis_url = match url {
         Some(value) => value,