Bootstrap socket location from env variable

This commit adds functionality to create a IPC connector from a URL and
to bootstrap the IPC handler creation from an environment variable using
this new functionality.

Signed-off-by: Ionut Mihalcea <ionut.mihalcea@arm.com>

Author: ionut-arm

Cargo.toml

@@ -19,6 +19,7 @@ log = "0.4.11"
 derivative = "2.1.1"
 zeroize = "1.1.0"
 users = "0.10.0"
+url = "2.2.0"
 
 [dev-dependencies]
 mockstream = "0.0.3"

src/core/basic_client.rs

@@ -202,7 +202,7 @@ impl BasicClient {
     /// [`set_default_provider`](#method.set_default_provider)
     pub fn new(app_name: Option<String>) -> Result<Self> {
         let mut client = BasicClient {
-            op_client: Default::default(),
+            op_client: OperationClient::new()?,
             auth_data: Authentication::None,
             implicit_provider: ProviderID::Core,
         };

src/core/ipc_handler/mod.rs

@@ -1,12 +1,16 @@
 // Copyright 2020 Contributors to the Parsec project.
 // SPDX-License-Identifier: Apache-2.0
 //! Types implementing an abstraction over IPC channels
-use crate::error::Result;
+use crate::error::{ClientErrorKind, Error, Result};
 use std::io::{Read, Write};
 use std::time::Duration;
+use url::Url;
 
 pub mod unix_socket;
 
+/// Default timeout for client IPC requests.
+pub const DEFAULT_TIMEOUT: Duration = Duration::from_secs(60);
+
 /// This trait is created to allow the iterator returned by incoming to iterate over a trait object
 /// that implements both Read and Write.
 pub trait ReadWrite: Read + Write {}
@@ -23,3 +27,14 @@ pub trait Connect {
     /// Set timeout for all produced streams.
     fn set_timeout(&mut self, timeout: Option<Duration>);
 }
+
+/// Create an implementation of `Connect` from the socket URL
+pub fn connector_from_url(socket_url: Url) -> Result<Box<dyn Connect + Send + Sync>> {
+    match socket_url.scheme() {
+        "unix" => Ok(Box::from(unix_socket::Handler::new(
+            socket_url.path().into(),
+            Some(DEFAULT_TIMEOUT),
+        )?)),
+        _ => Err(Error::Client(ClientErrorKind::InvalidSocketUrl)),
+    }
+}

src/core/ipc_handler/unix_socket.rs

@@ -2,13 +2,14 @@
 // SPDX-License-Identifier: Apache-2.0
 //! Handler for Unix domain sockets
 use super::{Connect, ReadWrite};
-use crate::error::{ClientErrorKind, Result};
+use crate::error::{ClientErrorKind, Error, Result};
+use std::os::unix::fs::FileTypeExt;
 use std::os::unix::net::UnixStream;
 use std::path::PathBuf;
 use std::time::Duration;
 
-const DEFAULT_SOCKET_PATH: &str = "/run/parsec/parsec.sock";
-const DEFAULT_TIMEOUT: Duration = Duration::from_secs(60);
+/// Default socket path used by the service.
+pub const DEFAULT_SOCKET_PATH: &str = "/run/parsec/parsec.sock";
 
 /// IPC handler for Unix domain sockets
 #[derive(Debug, Clone)]
@@ -40,16 +41,25 @@ impl Connect for Handler {
 
 impl Handler {
     /// Create new client using given socket path and timeout duration
-    pub fn new(path: PathBuf, timeout: Option<Duration>) -> Self {
-        Handler { path, timeout }
+    pub fn new(path: PathBuf, timeout: Option<Duration>) -> Result<Self> {
+        if path.exists()
+            && std::fs::metadata(&path)
+                .map_err(|_| Error::Client(ClientErrorKind::InvalidSocketAddress))?
+                .file_type()
+                .is_socket()
+        {
+            Ok(Handler { path, timeout })
+        } else {
+            Err(Error::Client(ClientErrorKind::InvalidSocketAddress))
+        }
     }
 }
 
 impl Default for Handler {
     fn default() -> Self {
         Handler {
             path: DEFAULT_SOCKET_PATH.into(),
-            timeout: Some(DEFAULT_TIMEOUT),
+            timeout: Some(super::DEFAULT_TIMEOUT),
         }
     }
 }

src/core/operation_client.rs

@@ -40,8 +40,11 @@ impl OperationClient {
     /// seconds on reads and writes on the socket. It uses the version 1.0 wire protocol
     /// to form requests, the direct authentication method and protobuf format as
     /// content type.
-    pub fn new() -> OperationClient {
-        Default::default()
+    pub fn new() -> Result<OperationClient> {
+        Ok(OperationClient {
+            request_client: RequestClient::new()?,
+            ..Default::default()
+        })
     }
 
     fn operation_to_request(

src/core/request_client.rs

@@ -1,10 +1,11 @@
 // Copyright 2020 Contributors to the Parsec project.
 // SPDX-License-Identifier: Apache-2.0
 //! Request-level client
-use super::ipc_handler::{unix_socket, Connect};
+use super::ipc_handler::{self, unix_socket, Connect};
 use crate::error::{ClientErrorKind, Result};
 use derivative::Derivative;
 use parsec_interface::requests::{Request, Response};
+use std::env;
 use std::time::Duration;
 
 const DEFAULT_MAX_BODY_SIZE: usize = usize::max_value();
@@ -29,6 +30,18 @@ pub struct RequestClient {
 }
 
 impl RequestClient {
+    /// Creates a new `RequestClient`, bootstrapping the socket
+    /// location.
+    pub fn new() -> Result<Self> {
+        Ok(RequestClient {
+            ipc_handler: ipc_handler::connector_from_url(url::Url::parse(
+                &env::var("PARSEC_SERVICE_ENDPOINT")
+                    .unwrap_or(format!("unix:{}", unix_socket::DEFAULT_SOCKET_PATH)),
+            )?)?,
+            max_body_size: DEFAULT_MAX_BODY_SIZE,
+        })
+    }
+
     /// Send a request and get a response.
     pub fn process_request(&self, request: Request) -> Result<Response> {
         // Try to connect once, wait for a timeout until trying again.

src/error.rs

@@ -44,6 +44,10 @@ pub enum ClientErrorKind {
     MissingParam,
     /// The requested resource was not found.
     NotFound,
+    /// The socket address provided is not valid
+    InvalidSocketAddress,
+    /// The socket URL is invalid
+    InvalidSocketUrl,
 }
 
 impl From<ClientErrorKind> for Error {
@@ -52,6 +56,12 @@ impl From<ClientErrorKind> for Error {
     }
 }
 
+impl From<url::ParseError> for Error {
+    fn from(_: url::ParseError) -> Self {
+        Error::Client(ClientErrorKind::InvalidSocketUrl)
+    }
+}
+
 impl fmt::Display for ClientErrorKind {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
@@ -67,7 +77,9 @@ impl fmt::Display for ClientErrorKind {
             ClientErrorKind::NoProvider => write!(f, "client is missing an implicit provider"),
             ClientErrorKind::NoAuthenticator => write!(f, "service is not reporting any authenticators or none of the reported ones are supported by the client"),
             ClientErrorKind::MissingParam => write!(f, "one of the `Option` parameters was required but was not provided"),
-            ClientErrorKind::NotFound => write!(f, "one of the resources required in the operation was not found")
+            ClientErrorKind::NotFound => write!(f, "one of the resources required in the operation was not found"),
+            ClientErrorKind::InvalidSocketAddress => write!(f, "the socket address provided in the URL is not valid"),
+            ClientErrorKind::InvalidSocketUrl => write!(f, "the socket URL is invalid"),
         }
     }
 }