-
Notifications
You must be signed in to change notification settings - Fork 9
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Collect agent info from sidecar (#701)
* Collect agent info from sidecar Signed-off-by: Bob Weinand <[email protected]> * Add comments and test for AgentInfo in sidecar Signed-off-by: Bob Weinand <[email protected]> --------- Signed-off-by: Bob Weinand <[email protected]>
- Loading branch information
Showing
10 changed files
with
300 additions
and
6 deletions.
There are no files selected for viewing
Some generated files are not rendered by default. Learn more about how customized files appear on GitHub.
Oops, something went wrong.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,243 @@ | ||
| // Copyright 2024-Present Datadog, Inc. https://www.datadoghq.com/ | ||
| // SPDX-License-Identifier: Apache-2.0 | ||
|
|
||
| //! This file contains code for fetching and sharing the info from the Datadog Agent. | ||
| //! It will keep one fetcher per Endpoint. The SidecarServer is expected to keep the AgentInfoGuard | ||
| //! alive for the lifetime of the session. | ||
| //! The fetcher will remain alive for a short while after all guards have been dropped. | ||
| //! It writes the raw agent response to shared memory at a fixed per-endpoint location, to be | ||
| //! consumed be tracers. | ||
|
|
||
| use crate::one_way_shared_memory::{open_named_shm, OneWayShmReader, OneWayShmWriter}; | ||
| use crate::primary_sidecar_identifier; | ||
| use base64::prelude::BASE64_URL_SAFE_NO_PAD; | ||
| use base64::Engine; | ||
| use data_pipeline::agent_info::schema::AgentInfoStruct; | ||
| use data_pipeline::agent_info::{fetch_info_with_state, FetchInfoStatus}; | ||
| use datadog_ipc::platform::NamedShmHandle; | ||
| use ddcommon::Endpoint; | ||
| use futures::future::Shared; | ||
| use futures::FutureExt; | ||
| use http::uri::PathAndQuery; | ||
| use manual_future::ManualFuture; | ||
| use std::ffi::CString; | ||
| use std::hash::{Hash, Hasher}; | ||
| use std::sync::{Arc, Mutex}; | ||
| use std::time::{Duration, Instant}; | ||
| use tokio::time::sleep; | ||
| use tracing::{error, warn}; | ||
| use zwohash::{HashMap, ZwoHasher}; | ||
|
|
||
| #[derive(Default, Clone)] | ||
| pub struct AgentInfos(Arc<Mutex<HashMap<Endpoint, AgentInfoFetcher>>>); | ||
|
|
||
| impl AgentInfos { | ||
| /// Ensures a fetcher for the endpoints agent info and keeps it alive for at least as long as | ||
| /// the returned guard exists. | ||
| pub fn query_for(&self, endpoint: Endpoint) -> AgentInfoGuard { | ||
| let mut infos_guard = self.0.lock().unwrap(); | ||
| if let Some(info) = infos_guard.get_mut(&endpoint) { | ||
| info.rc += 1; | ||
| } else { | ||
| infos_guard.insert( | ||
| endpoint.clone(), | ||
| AgentInfoFetcher::new(self.clone(), endpoint.clone()), | ||
| ); | ||
| } | ||
|
|
||
| AgentInfoGuard { | ||
| infos: self.clone(), | ||
| endpoint, | ||
| } | ||
| } | ||
| } | ||
|
|
||
| pub struct AgentInfoGuard { | ||
| infos: AgentInfos, | ||
| endpoint: Endpoint, | ||
| } | ||
|
|
||
| impl AgentInfoGuard { | ||
| pub fn get(&self) -> Shared<ManualFuture<AgentInfoStruct>> { | ||
| let infos_guard = self.infos.0.lock().unwrap(); | ||
| let infos = infos_guard.get(&self.endpoint).unwrap(); | ||
| infos.infos.clone() | ||
| } | ||
| } | ||
|
|
||
| impl Drop for AgentInfoGuard { | ||
| fn drop(&mut self) { | ||
| let mut infos_guard = self.infos.0.lock().unwrap(); | ||
| let info = infos_guard.get_mut(&self.endpoint).unwrap(); | ||
| info.last_update = Instant::now(); | ||
| info.rc -= 1; | ||
| } | ||
| } | ||
|
|
||
| pub struct AgentInfoFetcher { | ||
| /// Once the last_update is too old, we'll stop the fetcher. | ||
| last_update: Instant, | ||
| /// Will be kept alive forever if rc > 0. | ||
| rc: u32, | ||
| /// The initial fetch is an unresolved future (to be able to await on it), subsequent fetches | ||
| /// are simply directly replacing this with a resolved future. | ||
| infos: Shared<ManualFuture<AgentInfoStruct>>, | ||
| } | ||
|
|
||
| impl AgentInfoFetcher { | ||
| fn new(agent_infos: AgentInfos, endpoint: Endpoint) -> AgentInfoFetcher { | ||
| let (future, completer) = ManualFuture::new(); | ||
| tokio::spawn(async move { | ||
| let mut state: Option<String> = None; | ||
| let mut writer = None; | ||
| let mut completer = Some(completer); | ||
| let mut fetch_endpoint = endpoint.clone(); | ||
| let mut parts = fetch_endpoint.url.into_parts(); | ||
| parts.path_and_query = Some(PathAndQuery::from_static("/info")); | ||
| fetch_endpoint.url = hyper::Uri::from_parts(parts).unwrap(); | ||
| loop { | ||
| let fetched = fetch_info_with_state(&fetch_endpoint, state.as_deref()).await; | ||
| let mut complete_fut = None; | ||
| { | ||
| let mut infos_guard = agent_infos.0.lock().unwrap(); | ||
| let infos = infos_guard.get_mut(&endpoint).unwrap(); | ||
| if infos.rc == 0 && infos.last_update.elapsed().as_secs() > 60 { | ||
| break; | ||
| } | ||
| match fetched { | ||
| Ok(FetchInfoStatus::SameState) => {} | ||
| Ok(FetchInfoStatus::NewState(status)) => { | ||
| state = Some(status.state_hash); | ||
| if writer.is_none() { | ||
| writer = match OneWayShmWriter::<NamedShmHandle>::new(info_path( | ||
| &endpoint, | ||
| )) { | ||
| Ok(writer) => Some(writer), | ||
| Err(e) => { | ||
| error!("Failed acquiring an agent info writer: {e:?}"); | ||
| None | ||
| } | ||
| }; | ||
| } | ||
| if let Some(ref writer) = writer { | ||
| writer.write(&serde_json::to_vec(&status.info).unwrap()) | ||
| } | ||
| if let Some(completer) = completer { | ||
| complete_fut = Some(completer.complete(status.info)); | ||
| } else { | ||
| infos.infos = ManualFuture::new_completed(status.info).shared(); | ||
| } | ||
| completer = None; | ||
| } | ||
| Err(e) => { | ||
| // We'll just return the old values as long as the endpoint is | ||
| // unreachable. | ||
| warn!( | ||
| "The agent info for {} could not be fetched: {}", | ||
| fetch_endpoint.url, e | ||
| ); | ||
| } | ||
| } | ||
| } | ||
| if let Some(complete_fut) = complete_fut.take() { | ||
| complete_fut.await; | ||
| } | ||
| sleep(Duration::from_secs(60)).await; | ||
| } | ||
| agent_infos.0.lock().unwrap().remove(&endpoint); | ||
| }); | ||
|
|
||
| AgentInfoFetcher { | ||
| last_update: Instant::now(), | ||
| rc: 1, | ||
| infos: future.shared(), | ||
| } | ||
| } | ||
| } | ||
|
|
||
| fn info_path(endpoint: &Endpoint) -> CString { | ||
| let mut hasher = ZwoHasher::default(); | ||
| endpoint.hash(&mut hasher); | ||
| let mut path = format!( | ||
| "/ddinf{}-{}", | ||
| primary_sidecar_identifier(), | ||
| BASE64_URL_SAFE_NO_PAD.encode(hasher.finish().to_ne_bytes()), | ||
| ); | ||
| // datadog agent info, on macos we're restricted to 31 chars | ||
| path.truncate(31); // should not be larger than 31 chars, but be sure. | ||
| CString::new(path).unwrap() | ||
| } | ||
|
|
||
| pub struct AgentInfoReader { | ||
| reader: OneWayShmReader<NamedShmHandle, CString>, | ||
| info: Option<AgentInfoStruct>, | ||
| } | ||
|
|
||
| impl AgentInfoReader { | ||
| pub fn new(endpoint: &Endpoint) -> AgentInfoReader { | ||
| let path = info_path(endpoint); | ||
| AgentInfoReader { | ||
| reader: OneWayShmReader::new(open_named_shm(&path).ok(), path), | ||
| info: None, | ||
| } | ||
| } | ||
|
|
||
| pub fn read(&mut self) -> (bool, &Option<AgentInfoStruct>) { | ||
| let (updated, data) = self.reader.read(); | ||
| if updated { | ||
| match serde_json::from_slice(data) { | ||
| Ok(info) => self.info = Some(info), | ||
| Err(e) => error!("Failed deserializing the agent info: {e:?}"), | ||
| } | ||
| } | ||
| (updated, &self.info) | ||
| } | ||
| } | ||
|
|
||
| #[cfg(test)] | ||
| mod tests { | ||
| use super::*; | ||
| use httpmock::prelude::*; | ||
|
|
||
| const TEST_INFO: &str = r#"{ | ||
| "config": { | ||
| "default_env": "testenv" | ||
| } | ||
| }"#; | ||
|
|
||
| const TEST_INFO_HASH: &str = "8c732aba385d605b010cd5bd12c03fef402eaefce989f0055aa4c7e92fe30077"; | ||
|
|
||
| #[cfg_attr(miri, ignore)] | ||
| #[tokio::test] | ||
| async fn test_fetch_info_without_state() { | ||
| let server = MockServer::start(); | ||
| let mock = server | ||
| .mock_async(|when, then| { | ||
| when.path("/info"); | ||
| then.status(200) | ||
| .header("content-type", "application/json") | ||
| .header("datadog-agent-state", TEST_INFO_HASH) | ||
| .body(TEST_INFO); | ||
| }) | ||
| .await; | ||
| let endpoint = Endpoint::from_url(server.url("/").parse().unwrap()); | ||
| let agent_infos = AgentInfos::default(); | ||
|
|
||
| let mut reader = AgentInfoReader::new(&endpoint); | ||
| assert_eq!(reader.read(), (false, &None)); | ||
|
|
||
| let info = agent_infos.query_for(endpoint).get().await; | ||
| mock.assert(); | ||
| assert_eq!( | ||
| info.config.unwrap().default_env, | ||
| Some("testenv".to_string()) | ||
| ); | ||
|
|
||
| let (updated, info) = reader.read(); | ||
| assert!(updated); | ||
| assert_eq!( | ||
| info.as_ref().unwrap().config.as_ref().unwrap().default_env, | ||
| Some("testenv".to_string()) | ||
| ); | ||
| } | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.