statsig_rust/specs_adapter/
statsig_local_file_specs_adapter.rs

1use crate::hashing::djb2;
2use crate::specs_adapter::{SpecsAdapter, SpecsSource, SpecsUpdate, SpecsUpdateListener};
3use crate::specs_response::spec_types::SpecsResponseFull;
4use crate::specs_response::spec_types_encoded::DecodedSpecsResponse;
5use crate::statsig_err::StatsigErr;
6use crate::{log_e, log_w, StatsigOptions, StatsigRuntime};
7use async_trait::async_trait;
8use chrono::Utc;
9use parking_lot::RwLock;
10use std::sync::Arc;
11use std::time::Duration;
12
13use super::{SpecsInfo, StatsigHttpSpecsAdapter};
14
15const TAG: &str = stringify!(StatsigLocalFileSpecsAdapter);
16
17pub struct StatsigLocalFileSpecsAdapter {
18    file_path: String,
19    listener: RwLock<Option<Arc<dyn SpecsUpdateListener>>>,
20    http_adapter: StatsigHttpSpecsAdapter,
21}
22
23impl StatsigLocalFileSpecsAdapter {
24    #[must_use]
25    pub fn new(
26        sdk_key: &str,
27        output_directory: &str,
28        specs_url: Option<String>,
29        fallback_to_statsig_api: bool,
30        disable_network: bool,
31    ) -> Self {
32        let hashed_key = djb2(sdk_key);
33        let file_path = format!("{output_directory}/{hashed_key}_specs.json");
34
35        let options = StatsigOptions {
36            specs_url,
37            disable_network: Some(disable_network),
38            fallback_to_statsig_api: Some(fallback_to_statsig_api),
39            ..Default::default()
40        };
41
42        Self {
43            file_path,
44            listener: RwLock::new(None),
45            http_adapter: StatsigHttpSpecsAdapter::new(sdk_key, Some(&options), None),
46        }
47    }
48
49    pub async fn fetch_and_write_to_file(&self) -> Result<(), StatsigErr> {
50        let specs_info = match self.read_specs_from_file() {
51            Ok(Some(specs)) => SpecsInfo {
52                lcut: Some(specs.time),
53                checksum: specs.checksum,
54                zstd_dict_id: None, // For backwards compatibility, we only store uncompressed specs
55                source: SpecsSource::Adapter("FileBased".to_owned()),
56                source_api: None,
57            },
58            _ => SpecsInfo::empty(),
59        };
60
61        let data = match self.http_adapter.fetch_specs_from_network(specs_info).await {
62            Ok(response) => match String::from_utf8(response.data) {
63                Ok(data) => data,
64                Err(e) => {
65                    return Err(StatsigErr::SerializationError(e.to_string()));
66                }
67            },
68            Err(e) => {
69                return Err(StatsigErr::NetworkError(e));
70            }
71        };
72
73        if let Some(response) = self.parse_specs_data_to_full_response(&data) {
74            if response.has_updates {
75                self.write_specs_to_file(&data);
76            }
77        }
78
79        Ok(())
80    }
81
82    pub fn resync_from_file(&self) -> Result<(), StatsigErr> {
83        let data = match std::fs::read_to_string(&self.file_path) {
84            Ok(data) => data,
85            Err(e) => {
86                return Err(StatsigErr::FileError(e.to_string()));
87            }
88        };
89
90        match &self
91            .listener
92            .try_read_for(std::time::Duration::from_secs(5))
93        {
94            Some(lock) => match lock.as_ref() {
95                Some(listener) => listener.did_receive_specs_update(SpecsUpdate {
96                    data: data.into_bytes(),
97                    source: SpecsSource::Adapter("FileBased".to_owned()),
98                    received_at: Utc::now().timestamp_millis() as u64,
99                    source_api: None,
100                }),
101                None => Err(StatsigErr::UnstartedAdapter("Listener not set".to_string())),
102            },
103            None => Err(StatsigErr::LockFailure(
104                "Failed to acquire read lock on listener".to_string(),
105            )),
106        }
107    }
108
109    fn read_specs_from_file(&self) -> Result<Option<SpecsResponseFull>, StatsigErr> {
110        if !std::path::Path::new(&self.file_path).exists() {
111            return Ok(None);
112        }
113
114        let data = match std::fs::read_to_string(&self.file_path) {
115            Ok(data) => data,
116            Err(e) => {
117                return Err(StatsigErr::FileError(e.to_string()));
118            }
119        };
120
121        Ok(self.parse_specs_data_to_full_response(&data))
122    }
123
124    fn parse_specs_data_to_full_response(&self, data: &str) -> Option<SpecsResponseFull> {
125        let mut place = SpecsResponseFull::default();
126        match DecodedSpecsResponse::from_slice(data.as_bytes(), &mut place, None) {
127            Ok(_) => Some(place),
128            Err(e) => {
129                log_w!(TAG, "Failed to parse specs data: {}", e);
130                None
131            }
132        }
133    }
134
135    fn write_specs_to_file(&self, data: &str) {
136        match std::fs::write(&self.file_path, data) {
137            Ok(()) => (),
138            Err(e) => log_w!(TAG, "Failed to write specs to file: {}", e),
139        }
140    }
141}
142
143#[async_trait]
144impl SpecsAdapter for StatsigLocalFileSpecsAdapter {
145    async fn start(
146        self: Arc<Self>,
147        _statsig_runtime: &Arc<StatsigRuntime>,
148    ) -> Result<(), StatsigErr> {
149        self.resync_from_file()
150    }
151
152    fn initialize(&self, listener: Arc<dyn SpecsUpdateListener>) {
153        match self
154            .listener
155            .try_write_for(std::time::Duration::from_secs(5))
156        {
157            Some(mut lock) => *lock = Some(listener),
158            None => {
159                log_e!(TAG, "Failed to acquire write lock on listener");
160            }
161        }
162    }
163
164    async fn shutdown(
165        &self,
166        _timeout: Duration,
167        _statsig_runtime: &Arc<StatsigRuntime>,
168    ) -> Result<(), StatsigErr> {
169        Ok(())
170    }
171
172    async fn schedule_background_sync(
173        self: Arc<Self>,
174        _statsig_runtime: &Arc<StatsigRuntime>,
175    ) -> Result<(), StatsigErr> {
176        Ok(())
177    }
178
179    fn get_type_name(&self) -> String {
180        stringify!(StatsigLocalFileSpecsAdapter).to_string()
181    }
182}
statsig_rust/specs_adapter/statsig_local_file_specs_adapter.rs

statsig_rust/specs_adapter/
statsig_local_file_specs_adapter.rs
