fix: update byte array base64 prefix

.github/workflows/ci.yaml

@@ -79,8 +79,8 @@ jobs:
       # TODO: This needs to be updated once wasi-otel is merged into big Spin.
       - name: Setup Spin
         run: |
-          curl -LO https://github.com/asteurer/spin/releases/download/v0.1.0-otel/spin-linux-amd64
-          echo "9b2bbcc98ddf2faeb31a8feda3672df0562052150abc96acf5351cc7d3b51f9a  spin-linux-amd64" | sha256sum --check
+          curl -LO https://github.com/asteurer/spin/releases/download/v0.2.0-otel/spin-linux-amd64
+          echo "94e31a56502026f83c12a843cf4aa7f3b5bf1d5a97fd18348fe78ab7f2ba4548  spin-linux-amd64" | sha256sum --check
           chmod +x spin-linux-amd64
           mkdir -p $HOME/.local/bin
           mv spin-linux-amd64 $HOME/.local/bin/spin

rust/src/logs/conversion.rs

@@ -61,7 +61,8 @@ impl<'a> Serialize for AnyValueWrapper<'a> {
             opentelemetry::logs::AnyValue::Bytes(bytes) => {
                 // This is a workaround for JSON not having a way to differentiate between an array of bytes and an array of integers.
                 let encoded = base64::engine::general_purpose::STANDARD.encode(bytes.as_ref());
-                serializer.serialize_str(&format!("{{base64}}:{}", encoded))
+                serializer
+                    .serialize_str(&format!("data:application/octet-stream;base64,{}", encoded))
             }
             opentelemetry::logs::AnyValue::ListAny(list) => {
                 serialize_seq!(list, serializer, |v| &AnyValueWrapper(v))
@@ -129,7 +130,7 @@ mod tests {
             "key2": 123.456,
             "key3": 41,
             //'Hello, world!' encoded to base64
-            "key4": "{base64}:SGVsbG8sIHdvcmxkIQ==",
+            "key4": "data:application/octet-stream;base64,SGVsbG8sIHdvcmxkIQ==",
             "key5": "This is a string",
             "key6": [1, 2, 3],
             "key7": {

ts/src/logs.test.ts

@@ -29,7 +29,7 @@ describe('logAnyValueToWasi', () => {
       key2: 123.456,
       key3: 41,
       // 'Hello, world!' encoded to base64
-      key4: '{base64}:SGVsbG8sIHdvcmxkIQ==',
+      key4: 'data:application/octet-stream;base64,SGVsbG8sIHdvcmxkIQ==',
       key5: 'This is a string',
       key6: [1, 2, 3],
       key7: {

ts/src/logs.ts

@@ -57,7 +57,10 @@ function logAttributesToWasi(attrs: AnyValueMap): WasiKeyValue[] {
 
 export function logAnyValueToWasi(v: AnyValue): string {
   if (v instanceof Uint8Array) {
-    return JSON.stringify('{base64}:' + Buffer.from(v).toString('base64'));
+    return JSON.stringify(
+      'data:application/octet-stream;base64,' +
+        Buffer.from(v).toString('base64')
+    );
   } else if (v === null || v === undefined) {
     return 'null';
   } else if (typeof v === 'string') {

ts/types/interfaces/wasi-otel-types.d.ts

@@ -8,6 +8,10 @@ declare module 'wasi:otel/types@0.2.0-draft' {
    * 
    * This corresponds with the `AnyValue` type defined in the [attribute spec](https://opentelemetry.io/docs/specs/otel/common/#anyvalue).
    * Because WIT doesn't support recursive types, the data needs to be serialized. JSON is used as the encoding format.
+   * 
+   * Byte arrays require special encoding since JSON cannot distinguish them from number arrays.
+   * They are base64-encoded with a prefix that follows the Data URI RFC 2397 convention:
+   * `data:application/octet-stream;base64,<BASE64_ENCODED_BYTES>`
    */
   export type Value = string;
   /**

ts/wit/types.wit

@@ -14,6 +14,10 @@ interface types {
     ///
     /// This corresponds with the `AnyValue` type defined in the [attribute spec](https://opentelemetry.io/docs/specs/otel/common/#anyvalue).
     /// Because WIT doesn't support recursive types, the data needs to be serialized. JSON is used as the encoding format.
+    ///
+    /// Byte arrays require special encoding since JSON cannot distinguish them from number arrays.
+    /// They are base64-encoded with a prefix that follows the Data URI RFC 2397 convention: 
+    /// `data:application/octet-stream;base64,<BASE64_ENCODED_BYTES>`
     type value = string;
 
     /// An immutable representation of the entity producing telemetry as attributes.

wit/types.wit

@@ -14,6 +14,10 @@ interface types {
     ///
     /// This corresponds with the `AnyValue` type defined in the [attribute spec](https://opentelemetry.io/docs/specs/otel/common/#anyvalue).
     /// Because WIT doesn't support recursive types, the data needs to be serialized. JSON is used as the encoding format.
+    ///
+    /// Byte arrays require special encoding since JSON cannot distinguish them from number arrays.
+    /// They are base64-encoded with a prefix that follows the Data URI RFC 2397 convention: 
+    /// `data:application/octet-stream;base64,<BASE64_ENCODED_BYTES>`
     type value = string;
 
     /// An immutable representation of the entity producing telemetry as attributes.