Add template engine to evaluate task commands

The field "run" is renamed to "command" in a few places. We only use the
evaluated command string for TaskInput now, not the TaskID or arguments.

8 files changed, 200 insertions, 15 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 3842c9e..68b4cad 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -36,14 +36,47 @@ checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
 
 [[package]]
 name = "block-buffer"
+version = "0.7.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c0940dc441f31689269e10ac70eb1002a3a1d3ad1390e030043662eb7fe4688b"
+dependencies = [
+ "block-padding",
+ "byte-tools",
+ "byteorder",
+ "generic-array 0.12.4",
+]
+
+[[package]]
+name = "block-buffer"
 version = "0.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4152116fd6e9dadb291ae18fc1ec3575ed6d84c29642d97890f4b4a3417297e4"
 dependencies = [
- "generic-array",
+ "generic-array 0.14.4",
+]
+
+[[package]]
+name = "block-padding"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fa79dedbb091f449f1f39e53edf88d5dbe95f895dae6135a8d7b881fb5af73f5"
+dependencies = [
+ "byte-tools",
 ]
 
 [[package]]
+name = "byte-tools"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e3b5ca7a04898ad4bcd41c90c5285445ff5b791899bb1b0abdd2a2aa791211d7"
+
+[[package]]
+name = "byteorder"
+version = "1.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "14c189c53d098945499cdfa7ecc63567cf3886b3332b312a5b4585d8d3a6a610"
+
+[[package]]
 name = "cc"
 version = "1.0.70"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -190,11 +223,20 @@ dependencies = [
 
 [[package]]
 name = "digest"
+version = "0.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f3d0c8c8752312f9713efd397ff63acb9f85585afbf179282e720e7704954dd5"
+dependencies = [
+ "generic-array 0.12.4",
+]
+
+[[package]]
+name = "digest"
 version = "0.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d3dd60d1080a57a05ab032377049e0591415d2b31afd7028356dbf3cc6dcb066"
 dependencies = [
- "generic-array",
+ "generic-array 0.14.4",
 ]
 
 [[package]]
@@ -204,6 +246,12 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "56899898ce76aaf4a0f24d914c97ea6ed976d42fec6ad33fcbb0a1103e07b2b0"
 
 [[package]]
+name = "fake-simd"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e88a8acf291dafb59c2d96e8f59828f3838bb1a70398823ade51a84de6a6deed"
+
+[[package]]
 name = "filetime"
 version = "0.2.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -239,6 +287,15 @@ checksum = "3dcaa9ae7725d12cdb85b3ad99a434db70b468c09ded17e012d86b5c1010f7a7"
 
 [[package]]
 name = "generic-array"
+version = "0.12.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ffdf9f34f1447443d37393cc6c2b8313aebddcd96906caf34e54c68d8e57d7bd"
+dependencies = [
+ "typenum",
+]
+
+[[package]]
+name = "generic-array"
 version = "0.14.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "501466ecc8a30d1d3b7fc9229b122b2ce8ed6e9d9223f1138d4babb253e51817"
@@ -282,6 +339,20 @@ dependencies = [
 ]
 
 [[package]]
+name = "handlebars"
+version = "4.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "66b09e2322d20d14bc2572401ce7c1d60b4748580a76c230ed9c1f8938f0c833"
+dependencies = [
+ "log",
+ "pest",
+ "pest_derive",
+ "quick-error",
+ "serde",
+ "serde_json",
+]
+
+[[package]]
 name = "hashbrown"
 version = "0.11.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -401,6 +472,12 @@ dependencies = [
 ]
 
 [[package]]
+name = "maplit"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3e2e65a1a2e43cfcb47a895c4c8b10d1f4a61097f9f254f183aee60cad9c651d"
+
+[[package]]
 name = "maybe-uninit"
 version = "2.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -496,6 +573,12 @@ dependencies = [
 
 [[package]]
 name = "opaque-debug"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2839e79665f131bdb5782e51f2c6c9599c133c6098982a54c794358bf432529c"
+
+[[package]]
+name = "opaque-debug"
 version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "624a8340c38c1b80fd549087862da4ba43e08858af025b236e509b6649fc13d5"
@@ -507,6 +590,49 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6acbef58a60fe69ab50510a55bc8cdd4d6cf2283d27ad338f54cb52747a9cf2d"
 
 [[package]]
+name = "pest"
+version = "2.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "10f4872ae94d7b90ae48754df22fd42ad52ce740b8f370b03da4835417403e53"
+dependencies = [
+ "ucd-trie",
+]
+
+[[package]]
+name = "pest_derive"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "833d1ae558dc601e9a60366421196a8d94bc0ac980476d0b67e1d0988d72b2d0"
+dependencies = [
+ "pest",
+ "pest_generator",
+]
+
+[[package]]
+name = "pest_generator"
+version = "2.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "99b8db626e31e5b81787b9783425769681b347011cc59471e33ea46d2ea0cf55"
+dependencies = [
+ "pest",
+ "pest_meta",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "pest_meta"
+version = "2.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "54be6e404f5317079812fc8f9f5279de376d8856929e21c184ecf6bbd692a11d"
+dependencies = [
+ "maplit",
+ "pest",
+ "sha-1",
+]
+
+[[package]]
 name = "ppv-lite86"
 version = "0.2.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -555,6 +681,12 @@ dependencies = [
 ]
 
 [[package]]
+name = "quick-error"
+version = "2.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a993555f31e5a609f617c12db6250dedcac1b0a85076912c436e6fc9b2c8e6a3"
+
+[[package]]
 name = "quote"
 version = "1.0.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -649,6 +781,7 @@ name = "rebel"
 version = "0.1.0"
 dependencies = [
  "clap",
+ "handlebars",
  "hex",
  "ipc-channel",
  "libc",
@@ -752,16 +885,28 @@ dependencies = [
 ]
 
 [[package]]
+name = "sha-1"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f7d94d0bede923b3cea61f3f1ff57ff8cdfd77b400fb8f9998949e0cf04163df"
+dependencies = [
+ "block-buffer 0.7.3",
+ "digest 0.8.1",
+ "fake-simd",
+ "opaque-debug 0.2.3",
+]
+
+[[package]]
 name = "sha2"
 version = "0.9.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b69f9a4c9740d74c5baa3fd2e547f9525fa8088a8a958e0ca2409a514e33f5fa"
 dependencies = [
- "block-buffer",
+ "block-buffer 0.9.0",
  "cfg-if 1.0.0",
  "cpufeatures",
- "digest",
- "opaque-debug",
+ "digest 0.9.0",
+ "opaque-debug 0.3.0",
 ]
 
 [[package]]
@@ -891,6 +1036,12 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b63708a265f51345575b27fe43f9500ad611579e764c79edbc2037b1121959ec"
 
 [[package]]
+name = "ucd-trie"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "56dee185309b50d1f11bfedef0fe6d036842e3fb77413abef29f8f8d1c5d4c1c"
+
+[[package]]
 name = "unicode-normalization"
 version = "0.1.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
diff --git a/Cargo.toml b/Cargo.toml
index e746584..5af429f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,6 +9,7 @@ edition = "2018"
 
 [dependencies]
 clap = "3.0.0-beta.2"
+handlebars = "4.1.3"
 hex = { version = "0.4.3", features = ["std", "serde"] }
 ipc-channel = { git = "https://github.com/servo/ipc-channel.git" }
 libc = "0.2.84"
diff --git a/src/executor.rs b/src/executor.rs
index 2440d51..b35f6a4 100644
--- a/src/executor.rs
+++ b/src/executor.rs
@@ -6,6 +6,7 @@ use crate::{
 	context::*,
 	paths, resolve, runner,
 	task::*,
+	template::TemplateEngine,
 	types::*,
 	util::{cjson, error::*, fs},
 };
@@ -24,11 +25,10 @@ const TASK_ENV: &[(&str, &str)] = &[
 
 #[derive(Clone, Debug, Serialize)]
 struct TaskInput<'ctx> {
-	pub task: &'ctx TaskRef<'ctx>,
 	pub inherit: Option<&'ctx InputHash>,
 	pub depends: &'ctx HashMap<DependencyHash, Dependency>,
 	pub output: &'ctx HashMap<String, String>,
-	pub run: &'ctx str,
+	pub command: &'ctx str,
 	pub env: &'ctx HashMap<String, String>,
 }
 
@@ -80,6 +80,7 @@ pub struct Executor<'ctx> {
 	tasks_done: HashMap<TaskRef<'ctx>, TaskMeta>,
 	rdeps: HashMap<TaskRef<'ctx>, Vec<TaskRef<'ctx>>>,
 	env: HashMap<String, String>,
+	tpl: TemplateEngine,
 }
 
 impl<'ctx> Executor<'ctx> {
@@ -96,6 +97,7 @@ impl<'ctx> Executor<'ctx> {
 			tasks_done: HashMap::new(),
 			rdeps: HashMap::new(),
 			env,
+			tpl: TemplateEngine::new(),
 		};
 
 		for task in taskset {
@@ -154,7 +156,7 @@ impl<'ctx> Executor<'ctx> {
 	}
 
 	fn run_one(&self, task_ref: &TaskRef, runner: &impl runner::Runner) -> Result<TaskMeta> {
-		let task_def = &self.ctx[&task_ref.id];
+		let task_def = &self.ctx[task_ref.id];
 		let task_deps = self.task_deps(task_ref);
 		let task_output = task_def
 			.output
@@ -178,12 +180,15 @@ impl<'ctx> Executor<'ctx> {
 				(Vec::new(), None)
 			};
 
+		let command = self.tpl.eval(&task_def, &task_ref.args).with_context(|| {
+			format!("Failed to evaluate command template for task {}", task_ref)
+		})?;
+
 		let input_hash = TaskInput {
-			task: &task_ref,
 			inherit: inherit_hash,
 			depends: &task_deps,
 			output: &task_output,
-			run: &task_def.action.run,
+			command: &command,
 			env: &env,
 		}
 		.input_hash();
@@ -202,7 +207,7 @@ impl<'ctx> Executor<'ctx> {
 
 		let task = runner::Task {
 			id: task_ref.id.clone(),
-			run: task_def.action.run.clone(),
+			command,
 			input_hash,
 			inherit: inherit_chain.clone(),
 			depends: task_deps.clone(),
diff --git a/src/main.rs b/src/main.rs
index f731cc4..27714a4 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -6,6 +6,7 @@ mod recipe;
 mod resolve;
 mod runner;
 mod task;
+mod template;
 mod types;
 mod unshare;
 mod util;
diff --git a/src/runner/mod.rs b/src/runner/mod.rs
index fec1550..1c169f4 100644
--- a/src/runner/mod.rs
+++ b/src/runner/mod.rs
@@ -8,7 +8,7 @@ use crate::{types::*, util::error::*};
 #[derive(Clone, Debug, Deserialize, Serialize)]
 pub struct Task {
 	pub id: TaskID,
-	pub run: String,
+	pub command: String,
 	pub input_hash: InputHash,
 	pub inherit: Vec<InputHash>,
 	pub depends: HashMap<DependencyHash, Dependency>,
diff --git a/src/runner/runc/run.rs b/src/runner/runc/run.rs
index ede6a89..a8d579e 100644
--- a/src/runner/runc/run.rs
+++ b/src/runner/runc/run.rs
@@ -218,7 +218,7 @@ pub fn handle_task(task: runner::Task) -> Result<HashMap<String, ArchiveHash>> {
 
 	let task_tmp_dir = paths::task_tmp_dir(&task.input_hash);
 
-	spec::generate_spec(task.run.as_str(), &task.env)
+	spec::generate_spec(task.command.as_str(), &task.env)
 		.save(paths::join(&[&task_tmp_dir, "config.json"]))
 		.map_err(Error::new)
 		.context("Failed to save runtime config")?;
diff --git a/src/runner/runc/spec.rs b/src/runner/runc/spec.rs
index 0b0d4a0..051efc4 100644
--- a/src/runner/runc/spec.rs
+++ b/src/runner/runc/spec.rs
@@ -6,7 +6,7 @@ use serde_json::json;
 
 use crate::{paths, unshare};
 
-pub fn generate_spec(run: &str, env: &HashMap<String, String>) -> runtime::Spec {
+pub fn generate_spec(command: &str, env: &HashMap<String, String>) -> runtime::Spec {
 	let env_entries: Vec<String> = env.iter().map(|(k, v)| format!("{}={}", k, v)).collect();
 	runtime::Spec::deserialize(json!({
 		"ociVersion": "1.0.2",
@@ -19,7 +19,7 @@ pub fn generate_spec(run: &str, env: &HashMap<String, String>) -> runtime::Spec
 			"args": [
 				"sh",
 				"-ec",
-				run
+				command
 			],
 			"env": env_entries,
 			"cwd": paths::abs(paths::WORKDIR_PREFIX),
diff --git a/src/template.rs b/src/template.rs
new file mode 100644
index 0000000..035e09a
--- /dev/null
+++ b/src/template.rs
@@ -0,0 +1,27 @@
+use handlebars::Handlebars;
+
+use crate::{task::*, util::error::*};
+
+fn escape(s: &str) -> String {
+	format!("'{}'", s.replace("'", "'\\''"))
+}
+
+#[derive(Debug)]
+pub struct TemplateEngine(Handlebars<'static>);
+
+impl TemplateEngine {
+	pub fn new() -> Self {
+		let mut tpl = Handlebars::new();
+
+		tpl.set_strict_mode(true);
+		tpl.register_escape_fn(escape);
+
+		TemplateEngine(tpl)
+	}
+
+	pub fn eval(&self, task: &TaskDef, args: &TaskArgs) -> Result<String> {
+		self.0
+			.render_template(&task.action.run, args)
+			.map_err(Error::new)
+	}
+}