4 Units are talking, but LINK rarely works. Committing now for safety.

exercises/204_established_identities/scripts/set_build_identity.py

@@ -0,0 +1,23 @@
+import binascii
+import time
+from pathlib import Path
+
+Import("env")
+
+pioenv = env.subst("$PIOENV").upper()
+identity_path = Path(env.subst("$PROJECT_DIR")) / "identities" / f"{pioenv}.identity"
+
+if not identity_path.exists():
+    raise RuntimeError(f"Missing identity file for {pioenv}: {identity_path}")
+
+identity_hex = binascii.hexlify(identity_path.read_bytes()).decode("ascii")
+epoch = int(time.time())
+utc_tag = time.strftime("%Y%m%d_%H%M%S", time.gmtime(epoch))
+
+env.Append(
+    CPPDEFINES=[
+        ("LOCAL_IDENTITY_HEX", f'\\"{identity_hex}\\"'),
+        ("FW_BUILD_EPOCH", str(epoch)),
+        ("FW_BUILD_UTC", f'\\"{utc_tag}\\"'),
+    ]
+)