Add conditional compilation to early-boot-config

sources/api/early-boot-config/Cargo.toml

@@ -11,11 +11,13 @@ exclude = ["README.md"]
 
 [dependencies]
 apiclient = { path = "../apiclient" }
+base64 = "0.13"
 http = "0.2"
 log = "0.4"
 reqwest = { version = "0.10", default-features = false, features = ["blocking"] }
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1"
+serde-xml-rs = "0.4.1"
 simplelog = "0.9"
 snafu = "0.6"
 tokio = { version = "0.2", default-features = false, features = ["macros", "rt-threaded"] }

sources/api/early-boot-config/build.rs

@@ -4,8 +4,31 @@ use std::env;
 use std::fs::File;
 use std::io::Write;
 use std::path::PathBuf;
+use std::process;
 
 fn main() {
+    // The code below emits `cfg` operators to conditionally compile this program based on the
+    // current variant.
+    // TODO: Replace this approach when the build system supports ideas like "variant
+    // tags": https://github.com/bottlerocket-os/bottlerocket/issues/1260
+    println!("cargo:rerun-if-env-changed=VARIANT");
+    if let Ok(variant) = env::var("VARIANT") {
+        if variant == "aws-dev" {
+            println!("cargo:rustc-cfg=bottlerocket_platform=\"aws-dev\"");
+        } else if variant.starts_with("aws") {
+            println!("cargo:rustc-cfg=bottlerocket_platform=\"aws\"");
+        } else if variant.starts_with("vmware") {
+            println!("cargo:rustc-cfg=bottlerocket_platform=\"vmware\"");
+        } else {
+            eprintln!(
+            "For local builds, you must set the 'VARIANT' environment variable so we know which data \
+            provider to build. Valid values are the directories in models/src/variants/, for \
+            example 'aws-k8s-1.17'."
+            );
+            process::exit(1);
+        }
+    }
+
     // Check for environment variable "SKIP_README". If it is set,
     // skip README generation
     if env::var_os("SKIP_README").is_some() {