From d0e9bc04bef92e2570ab6c27d69a2ddeee282672 Mon Sep 17 00:00:00 2001
From: Neil Kakkar <neilkakkar@gmail.com>
Date: Wed, 8 May 2024 20:07:57 +0100
Subject: [PATCH] add mod

---
 feature-flags/src/team.rs | 133 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 133 insertions(+)
 create mode 100644 feature-flags/src/team.rs

diff --git a/feature-flags/src/team.rs b/feature-flags/src/team.rs
new file mode 100644
index 0000000..cfa54c3
--- /dev/null
+++ b/feature-flags/src/team.rs
@@ -0,0 +1,133 @@
+use std::sync::Arc;
+
+use crate::{api::FlagError, redis::Client};
+
+use serde::{Deserialize, Serialize};
+use tracing::instrument;
+
+
+// TRICKY: I'm still not sure where the :1: is coming from.
+// The Django prefix is `posthog` only.
+// It's from here: https://docs.djangoproject.com/en/4.2/topics/cache/#cache-versioning
+// F&!£%% on the bright side we don't use this functionality yet.
+// Will rely on integration tests to catch this.
+const TEAM_TOKEN_CACHE_PREFIX: &str = "posthog:1:team_token:";
+
+// TODO: Check what happens if json has extra stuff, does serde ignore it? Yes
+// Make sure we don't serialize and store team data in redis. Let main decide endpoint control this...
+// and track misses. Revisit if this becomes an issue.
+// because otherwise very annoying to keep this in sync with main django which has a lot of extra fields we need here.
+// will lead to inconsistent behaviour.
+// This is turning out to be very annoying, because we have django key prefixes to be mindful of as well.
+// Wonder if it would be better to make these caches independent? This generates that new problem of CRUD happening in Django,
+// which needs to update this cache immediately, so they can't really ever be independent.
+// True for both team cache and flags cache. Hmm. Just I guess need to add tests around the key prefixes...
+#[derive(Debug, Deserialize, Serialize)]
+pub struct Team {
+    pub id: i64,
+    pub name: String,
+    pub api_token: String,
+}
+
+impl Team {
+    /// Validates a token, and returns a team if it exists.
+    /// 
+    
+    #[instrument(skip_all)]
+    pub async fn from_redis(
+        client: Arc<dyn Client + Send + Sync>,
+        token: String,
+    ) -> Result<Team, FlagError> {
+
+        // TODO: Instead of failing here, i.e. if not in redis, fallback to pg
+        let serialized_team = client
+            .get(
+                format!("{TEAM_TOKEN_CACHE_PREFIX}{}", token)
+            )
+            .await
+            .map_err(|e| {
+                tracing::error!("failed to fetch data: {}", e);
+                // TODO: Can be other errors if serde_pickle destructuring fails?
+                FlagError::TokenValidationError
+            })?;
+        
+        let team: Team = serde_json::from_str(&serialized_team).map_err(|e| {
+            tracing::error!("failed to parse data to team: {}", e);
+            // TODO: Internal error, shouldn't send back to client
+            FlagError::RequestParsingError(e)
+        })?;
+
+        Ok(team)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::sync::Arc;
+    use anyhow::Error;
+
+    use crate::redis::RedisClient;
+    use rand::{distributions::Alphanumeric, Rng};
+
+    use super::*;
+
+    fn random_string(prefix: &str, length: usize) -> String {
+        let suffix: String = rand::thread_rng()
+            .sample_iter(Alphanumeric)
+            .take(length)
+            .map(char::from)
+            .collect();
+        format!("{}{}", prefix, suffix)
+    }
+
+    async fn insert_new_team_in_redis(client: Arc<RedisClient>) -> Result<Team, Error> {
+        let id = rand::thread_rng().gen_range(0..10_000_000);
+        let token = random_string("phc_", 12);
+        let team = Team {
+            id: id,
+            name: "team".to_string(),
+            api_token: token,
+        };
+
+        let serialized_team = serde_json::to_string(&team)?;
+        client
+            .set(
+                format!("{TEAM_TOKEN_CACHE_PREFIX}{}", team.api_token.clone()),
+                serialized_team,
+            )
+            .await?;
+
+        Ok(team)
+    }
+
+    #[tokio::test]
+    async fn test_fetch_team_from_redis() {
+        let client = RedisClient::new("redis://localhost:6379/".to_string())
+            .expect("Failed to create redis client");
+        let client = Arc::new(client);
+
+        let team = insert_new_team_in_redis(client.clone()).await.unwrap();
+
+        let target_token = team.api_token;
+
+        let team_from_redis = Team::from_redis(client.clone(), target_token.clone()).await.unwrap();
+        assert_eq!(
+            team_from_redis.api_token, target_token
+        );
+        assert_eq!(
+            team_from_redis.id, team.id
+        );
+    }
+
+    #[tokio::test]
+    async fn test_fetch_invalid_team_from_redis() {
+        let client = RedisClient::new("redis://localhost:6379/".to_string())
+            .expect("Failed to create redis client");
+        let client = Arc::new(client);
+
+        match Team::from_redis(client.clone(), "banana".to_string()).await {
+            Err(FlagError::TokenValidationError) => (),
+            _ => panic!("Expected TokenValidationError"),
+        };
+    }
+}