chore: add trace logging (#17)

Author: zshipko

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Revision history for extism-pdk
 
+## 1.2.0.0
+
+* Add bindings to `http_headers` Extism host funtion
+* Add `trace` level logging
+
 ## 1.1.0.0
 
 * Remove calls to free where Extism host expects to take ownership

examples/CountVowels.hs

@@ -22,6 +22,10 @@ isVowel c =
 countVowels = do
   -- Get input string from Extism host
   s <- input
+
+  -- Log input
+  () <- Extism.PDK.log LogInfo ("Got input: " ++ s)
+
   -- Calculate the number of vowels
   let count = length (filter isVowel s)
   -- Return a JSON object {"count": count} back to the host

extism-pdk.cabal

@@ -1,6 +1,6 @@
 cabal-version:      3.0
 name:               extism-pdk
-version:            1.1.0.0
+version:            1.2.0.0
 
 -- A short (one-line) description of the package.
 synopsis: Extism Plugin Development Kit

src/Extism/PDK.hs

@@ -103,22 +103,23 @@ setError msg = do
   extismSetError $ memoryOffset s
 
 -- | Log level
-data LogLevel = LogInfo | LogDebug | LogWarn | LogError
+data LogLevel = LogTrace | LogDebug | LogInfo | LogWarn | LogError deriving (Enum)
 
 -- | Log to configured log file
 log :: LogLevel -> String -> IO ()
-log LogInfo msg = do
-  s <- allocString msg
-  extismLogInfo (memoryOffset s)
-log LogDebug msg = do
-  s <- allocString msg
-  extismLogDebug (memoryOffset s)
-log LogWarn msg = do
-  s <- allocString msg
-  extismLogWarn (memoryOffset s)
-log LogError msg = do
-  s <- allocString msg
-  extismLogError (memoryOffset s)
+log level msg = do
+  configuredLevel <- extismGetLogLevel
+  if fromIntegral (fromEnum level) < configuredLevel
+    then return ()
+    else do
+      s <- allocString msg
+      let offs = memoryOffset s
+      case level of
+        LogTrace -> extismLogTrace offs
+        LogDebug -> extismLogDebug offs
+        LogInfo -> extismLogInfo offs
+        LogWarn -> extismLogWarn offs
+        LogError -> extismLogError offs
 
 -- Log with "error" level
 logError :: String -> IO ()
@@ -135,3 +136,7 @@ logDebug = Extism.PDK.log LogDebug
 -- Log with "warn" level
 logWarn :: String -> IO ()
 logWarn = Extism.PDK.log LogWarn
+
+-- Log with "trace" level
+logTrace :: String -> IO ()
+logTrace = Extism.PDK.log LogTrace

src/Extism/PDK/Bindings.hs

@@ -37,6 +37,10 @@ foreign import ccall "extism_log_debug" extismLogDebug :: MemoryOffset -> IO ()
 
 foreign import ccall "extism_log_error" extismLogError :: MemoryOffset -> IO ()
 
+foreign import ccall "extism_log_trace" extismLogTrace :: MemoryOffset -> IO ()
+
+foreign import ccall "extism_get_log_level" extismGetLogLevel :: IO Int32
+
 foreign import ccall "extism_store_u8" extismStoreU8 :: MemoryOffset -> Word8 -> IO ()
 
 foreign import ccall "extism_store_u64" extismStoreU64 :: MemoryOffset -> Word64 -> IO ()

src/extism-pdk.c

@@ -76,3 +76,7 @@ DEFINE(log_warn, void, ExtismPointer)
 void extism_log_warn(ExtismPointer p) { return _log_warn(p); }
 DEFINE(log_error, void, ExtismPointer)
 void extism_log_error(ExtismPointer p) { return _log_error(p); }
+DEFINE(log_trace, void, ExtismPointer)
+void extism_log_trace(ExtismPointer p) { return _log_trace(p); }
+DEFINE(get_log_level, int32_t)
+int32_t extism_get_log_level() { return _get_log_level(); }