Fall back to showing GraphViz source when GraphViz is not installed

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## [Unreleased]
 * Added new (empty) diagnostic page served from the server
 * Added better error messages for when a file is missing that's referenced by a Rojo project
+* Added support for visualization endpoints returning GraphViz source when Dot is not available
 
 ## [0.5.0 Alpha 2](https://github.com/LPGhatguy/rojo/releases/tag/v0.5.0-alpha.2) (January 28, 2019)
 * Added support for `.model.json` files, compatible with 0.4.x

Cargo.lock

@@ -345,7 +345,7 @@ dependencies = [
 
 [[package]]
 name = "env_logger"
-version = "0.5.13"
+version = "0.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "atty 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1252,7 +1252,7 @@ version = "0.5.0-alpha.2"
 dependencies = [
  "clap 2.32.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "csv 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "env_logger 0.5.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "env_logger 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "failure 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1929,7 +1929,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum deflate 0.7.19 (registry+https://github.com/rust-lang/crates.io-index)" = "8a6abb26e16e8d419b5c78662aa9f82857c2386a073da266840e474d5055ec86"
 "checksum dtoa 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "6d301140eb411af13d3115f9a562c85cc6b541ade9dfa314132244aaee7489dd"
 "checksum encoding_rs 0.8.14 (registry+https://github.com/rust-lang/crates.io-index)" = "a69d152eaa438a291636c1971b0a370212165ca8a75759eb66818c5ce9b538f7"
-"checksum env_logger 0.5.13 (registry+https://github.com/rust-lang/crates.io-index)" = "15b0a4d2e39f8420210be8b27eeda28029729e2fd4291019455016c348240c38"
+"checksum env_logger 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "afb070faf94c85d17d50ca44f6ad076bce18ae92f0037d350947240a36e9d42e"
 "checksum error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)" = "07e791d3be96241c77c43846b665ef1384606da2cd2a48730abe606a12906e02"
 "checksum failure 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "795bd83d3abeb9220f257e597aa0080a508b27533824adf336529648f6abf7e2"
 "checksum failure_derive 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "ea1063915fd7ef4309e222a5a07cf9c319fb9c7836b1f89b85458672dbb127e1"

server/Cargo.toml

@@ -22,7 +22,7 @@ bundle-plugin = []
 [dependencies]
 clap = "2.27"
 csv = "1.0"
-env_logger = "0.5"
+env_logger = "0.6"
 failure = "0.1.3"
 log = "0.4"
 maplit = "1.0.1"

server/src/bin.rs

@@ -20,9 +20,14 @@ fn make_path_absolute(value: &Path) -> PathBuf {
 }
 
 fn main() {
-    env_logger::Builder::from_default_env()
-        .default_format_timestamp(false)
-        .init();
+    {
+        let log_env = env_logger::Env::default()
+            .default_filter_or("warn");
+
+        env_logger::Builder::from_env(log_env)
+            .default_format_timestamp(false)
+            .init();
+    }
 
     let app = clap_app!(Rojo =>
         (version: env!("CARGO_PKG_VERSION"))

server/src/visualize.rs

@@ -5,6 +5,7 @@ use std::{
     process::{Command, Stdio},
 };
 
+use log::warn;
 use rbx_tree::RbxId;
 
 use crate::{
@@ -27,13 +28,21 @@ digraph RojoTree {
 "#;
 
 /// Compiles DOT source to SVG by invoking dot on the command line.
-pub fn graphviz_to_svg(source: &str) -> String {
-    let mut child = Command::new("dot")
+pub fn graphviz_to_svg(source: &str) -> Option<String> {
+    let command = Command::new("dot")
         .arg("-Tsvg")
         .stdin(Stdio::piped())
         .stdout(Stdio::piped())
-        .spawn()
-        .expect("Failed to spawn GraphViz process -- make sure it's installed in order to use /api/visualize");
+        .spawn();
+
+    let mut child = match command {
+        Ok(child) => child,
+        Err(_) => {
+            warn!("Failed to spawn GraphViz process to visualize current state.");
+            warn!("If you want pretty graphs, install GraphViz and make sure 'dot' is on your PATH!");
+            return None;
+        },
+    };
 
     {
         let stdin = child.stdin.as_mut().expect("Failed to open stdin");
@@ -41,7 +50,7 @@ pub fn graphviz_to_svg(source: &str) -> String {
     }
 
     let output = child.wait_with_output().expect("Failed to read stdout");
-    String::from_utf8(output.stdout).expect("Failed to parse stdout as UTF-8")
+    Some(String::from_utf8(output.stdout).expect("Failed to parse stdout as UTF-8"))
 }
 
 /// A Display wrapper struct to visualize an RbxSession as SVG.

server/src/web.rs

@@ -238,13 +238,21 @@ impl Server {
     fn handle_visualize_rbx(&self) -> Response {
         let rbx_session = self.live_session.rbx_session.lock().unwrap();
         let dot_source = format!("{}", VisualizeRbxSession(&rbx_session));
-        Response::svg(graphviz_to_svg(&dot_source))
+
+        match graphviz_to_svg(&dot_source) {
+            Some(svg) => Response::svg(svg),
+            None => Response::text(dot_source),
+        }
     }
 
     fn handle_visualize_imfs(&self) -> Response {
         let imfs = self.live_session.imfs.lock().unwrap();
         let dot_source = format!("{}", VisualizeImfs(&imfs));
-        Response::svg(graphviz_to_svg(&dot_source))
+
+        match graphviz_to_svg(&dot_source) {
+            Some(svg) => Response::svg(svg),
+            None => Response::text(dot_source),
+        }
     }
 
     fn handle_visualize_path_metadata(&self) -> Response {