manifest: add conditional interpolation syntax (#47)

* manifest: add optional interpolation syntax

* compiler: generalize conditional interpolation

* compiler: fix direct template spec handling

* compiler: track slot when conditions

* compiler: generalize conditional interpolation to envs

Author: nhynes

AGENTS.md

@@ -11,3 +11,7 @@
 * Make error messages and spans as helpful to devs as possible. Rust error messaging is a great example of usability
     - Create UI tests whenever adding a new error type or variant. From the perspective of a dev using the software, ensure that the error is helpful.
 * When adding new crates, make sure to update the dockerfiles
+* The compiler should try to support older versions of the manifest format and scenario IR as long as it would not introduce an undue amount of complexity or legacy code to maintain.
+    - If supporting previous versions is feasible, later versions of the compiler take the old versions but output the later version of compiler outputs.
+* When a breaking change is made, you may need to bump versions of any of: the manifest format, the IR, the docker/images.json version series. If you bump the CLI docker image series, also update README.md to have the latest floating version.
+    - Do not update versions in tests or examples unless they changed in a breaking way and NEED the newer version.

README.md

@@ -54,7 +54,7 @@ If you want `amber` on your PATH, move it into a directory that’s already on P
 ### Option B: Use the Dockerized CLI
 
 ```sh
-docker run --rm -v "$PWD":/work -w /work ghcr.io/rdi-foundation/amber-cli:v0.2 --help
+docker run --rm -v "$PWD":/work -w /work ghcr.io/rdi-foundation/amber-cli:v0.3 --help
 ```
 
 ## Tutorial
@@ -102,7 +102,7 @@ amber compile amber-demo/parent.json --dot -
 If you're using the Dockerized CLI, replace `amber` with:
 
 ```sh
-docker run --rm -v "$PWD":/work -w /work ghcr.io/rdi-foundation/amber-cli:v0.2
+docker run --rm -v "$PWD":/work -w /work ghcr.io/rdi-foundation/amber-cli:v0.3
 ```
 
 ### 3) Generate Docker Compose and run
@@ -127,14 +127,14 @@ Direct output only supports components that use `program.path`.
 - macOS: `/usr/bin/sandbox-exec`
 
 The Docker Compose output references the router, provisioner, and helper images used to
-enforce the wiring and provision mesh identities: `ghcr.io/rdi-foundation/amber-router:v1`,
-`ghcr.io/rdi-foundation/amber-provisioner:v1`, and `ghcr.io/rdi-foundation/amber-helper:v1`.
+enforce the wiring and provision mesh identities: `ghcr.io/rdi-foundation/amber-router:v0.1`,
+`ghcr.io/rdi-foundation/amber-provisioner:v0.1`, and `ghcr.io/rdi-foundation/amber-helper:v0.2`.
 Docker Compose will pull them automatically;
 if you're in a restricted environment, pre-pull them ahead of time.
 
 Some scenarios also use the Docker gateway component to scope Docker Engine API access
 per component. In that case, the compose output will reference
-`ghcr.io/rdi-foundation/amber-docker-gateway:v1`.
+`ghcr.io/rdi-foundation/amber-docker-gateway:v0.1`.
 
 If you're working in this repo, the internal image list and tags live in
 `docker/images.json`; CI publishes and verifies those tags on `main`.

cli/src/main.rs

@@ -50,7 +50,7 @@ use amber_mesh::{
 use amber_resolver::Resolver;
 use amber_router as router;
 use amber_scenario::{SCENARIO_IR_SCHEMA, ScenarioIr};
-use amber_template::{RuntimeTemplateContext, TemplatePart, TemplateSpec};
+use amber_template::{ProgramArgTemplate, RuntimeTemplateContext, TemplatePart, TemplateSpec};
 use base64::Engine as _;
 use clap::{ArgAction, Args, Parser, Subcommand};
 use miette::{
@@ -1918,7 +1918,16 @@ fn decode_template_spec_program(raw_b64: &str) -> Result<String> {
         .entrypoint
         .first()
         .ok_or_else(|| miette::miette!("template spec program entrypoint is empty"))?;
-    render_template_string_literal(path_template)
+    render_program_arg_template_literal(path_template)
+}
+
+fn render_program_arg_template_literal(arg: &ProgramArgTemplate) -> Result<String> {
+    let ProgramArgTemplate::Arg(parts) = arg else {
+        return Err(miette::miette!(
+            "internal error: template spec program entrypoint starts with a conditional arg group"
+        ));
+    };
+    render_template_string_literal(parts)
 }
 
 fn render_template_string_literal(parts: &[TemplatePart]) -> Result<String> {