Add support for file based configuration (library-config)

Author: iamluc

Diff for: Cargo.lock

@@ -406,9 +406,9 @@ clang_format_fix:
 cbindgen: remove_cbindgen generate_cbindgen
 
 remove_cbindgen:
-	rm -f components-rs/ddtrace.h components-rs/live-debugger.h components-rs/telemetry.h components-rs/sidecar.h components-rs/common.h components-rs/crashtracker.h
+	rm -f components-rs/ddtrace.h components-rs/live-debugger.h components-rs/telemetry.h components-rs/sidecar.h components-rs/common.h components-rs/crashtracker.h components-rs/library-config.h
 
-generate_cbindgen: cbindgen_binary # Regenerate components-rs/ddtrace.h components-rs/live-debugger.h components-rs/telemetry.h components-rs/sidecar.h components-rs/common.h components-rs/crashtracker.h
+generate_cbindgen: cbindgen_binary # Regenerate components-rs/ddtrace.h components-rs/live-debugger.h components-rs/telemetry.h components-rs/sidecar.h components-rs/common.h components-rs/crashtracker.h components-rs/library-config.h
 	( \
 		$(command rustup && echo run nightly --) cbindgen --crate ddtrace-php  \
 			--config cbindgen.toml \
@@ -429,11 +429,14 @@ generate_cbindgen: cbindgen_binary # Regenerate components-rs/ddtrace.h componen
 		$(command rustup && echo run nightly --) cbindgen --crate datadog-crashtracker-ffi  \
 			--config crashtracker-ffi/cbindgen.toml \
 			--output $(PROJECT_ROOT)/components-rs/crashtracker.h; \
+		$(command rustup && echo run nightly --) cbindgen --crate datadog-library-config-ffi  \
+			--config library-config-ffi/cbindgen.toml \
+			--output $(PROJECT_ROOT)/components-rs/library-config.h; \
 		if test -d $(PROJECT_ROOT)/tmp; then \
 			mkdir -pv "$(BUILD_DIR)"; \
 			export CARGO_TARGET_DIR="$(BUILD_DIR)/target"; \
 		fi; \
-		cargo run -p tools -- $(PROJECT_ROOT)/components-rs/common.h $(PROJECT_ROOT)/components-rs/ddtrace.h $(PROJECT_ROOT)/components-rs/live-debugger.h $(PROJECT_ROOT)/components-rs/telemetry.h $(PROJECT_ROOT)/components-rs/sidecar.h $(PROJECT_ROOT)/components-rs/crashtracker.h  \
+		cargo run -p tools -- $(PROJECT_ROOT)/components-rs/common.h $(PROJECT_ROOT)/components-rs/ddtrace.h $(PROJECT_ROOT)/components-rs/live-debugger.h $(PROJECT_ROOT)/components-rs/telemetry.h $(PROJECT_ROOT)/components-rs/sidecar.h $(PROJECT_ROOT)/components-rs/crashtracker.h $(PROJECT_ROOT)/components-rs/library-config.h  \
 	)
 
 cbindgen_binary:

Diff for: Makefile

@@ -20,6 +20,7 @@ datadog-remote-config = { path = "../libdatadog/remote-config" }
 datadog-sidecar = { path = "../libdatadog/sidecar" }
 datadog-sidecar-ffi = { path = "../libdatadog/sidecar-ffi" }
 datadog-crashtracker-ffi = { path = "../libdatadog/crashtracker-ffi", default-features = false, features = ["collector"] }
+datadog-library-config-ffi = { path = "../libdatadog/library-config-ffi" }
 spawn_worker = { path = "../libdatadog/spawn_worker" }
 anyhow = { version = "1.0" }
 const-str = "0.5.6"

Diff for: components-rs/Cargo.toml

@@ -1289,6 +1289,121 @@ typedef struct ddog_crasht_Result_StringWrapper {
   };
 } ddog_crasht_Result_StringWrapper;
 
+typedef enum ddog_LibraryConfigName {
+  DDOG_LIBRARY_CONFIG_NAME_DD_TRACE_DEBUG = 0,
+  DDOG_LIBRARY_CONFIG_NAME_DD_SERVICE = 1,
+  DDOG_LIBRARY_CONFIG_NAME_DD_ENV = 2,
+  DDOG_LIBRARY_CONFIG_NAME_DD_VERSION = 3,
+  DDOG_LIBRARY_CONFIG_NAME_DD_PROFILING_ENABLED = 4,
+} ddog_LibraryConfigName;
+
+typedef struct ddog_Configurator ddog_Configurator;
+
+/**
+ * Ffi safe type representing an owned null-terminated C array
+ * Equivalent to a std::ffi::CString
+ */
+typedef struct ddog_CString {
+  /**
+   * Null terminated char array
+   */
+  char *ptr;
+  /**
+   * Length of the array, not counting the null-terminator
+   */
+  uintptr_t length;
+} ddog_CString;
+
+typedef struct ddog_LibraryConfig {
+  enum ddog_LibraryConfigName name;
+  struct ddog_CString value;
+} ddog_LibraryConfig;
+
+/**
+ * Holds the raw parts of a Rust Vec; it should only be created from Rust,
+ * never from C.
+ */
+typedef struct ddog_Vec_LibraryConfig {
+  const struct ddog_LibraryConfig *ptr;
+  uintptr_t len;
+  uintptr_t capacity;
+} ddog_Vec_LibraryConfig;
+
+/**
+ * A generic result type for when an operation may fail,
+ * or may return <T> in case of success.
+ */
+typedef enum ddog_Result_VecLibraryConfig_Tag {
+  DDOG_RESULT_VEC_LIBRARY_CONFIG_OK_VEC_LIBRARY_CONFIG,
+  DDOG_RESULT_VEC_LIBRARY_CONFIG_ERR_VEC_LIBRARY_CONFIG,
+} ddog_Result_VecLibraryConfig_Tag;
+
+typedef struct ddog_Result_VecLibraryConfig {
+  ddog_Result_VecLibraryConfig_Tag tag;
+  union {
+    struct {
+      struct ddog_Vec_LibraryConfig ok;
+    };
+    struct {
+      struct ddog_Error err;
+    };
+  };
+} ddog_Result_VecLibraryConfig;
+
+typedef struct ddog_Slice_CharSlice {
+  /**
+   * Should be non-null and suitably aligned for the underlying type. It is
+   * allowed but not recommended for the pointer to be null when the len is
+   * zero.
+   */
+  const ddog_CharSlice *ptr;
+  /**
+   * The number of elements (not bytes) that `.ptr` points to. Must be less
+   * than or equal to [isize::MAX].
+   */
+  uintptr_t len;
+} ddog_Slice_CharSlice;
+
+typedef struct ddog_ProcessInfo {
+  struct ddog_Slice_CharSlice args;
+  struct ddog_Slice_CharSlice envp;
+  ddog_CharSlice language;
+} ddog_ProcessInfo;
+
+typedef struct ddog_Slice_U8 {
+  /**
+   * Should be non-null and suitably aligned for the underlying type. It is
+   * allowed but not recommended for the pointer to be null when the len is
+   * zero.
+   */
+  const uint8_t *ptr;
+  /**
+   * The number of elements (not bytes) that `.ptr` points to. Must be less
+   * than or equal to [isize::MAX].
+   */
+  uintptr_t len;
+} ddog_Slice_U8;
+
+/**
+ * Use to represent bytes -- does not need to be valid UTF-8.
+ */
+typedef struct ddog_Slice_U8 ddog_ByteSlice;
+
+/**
+ * Ffi safe type representing a borrowed null-terminated C array
+ * Equivalent to a std::ffi::CStr
+ */
+typedef struct ddog_CStr {
+  /**
+   * Null terminated char array
+   */
+  char *ptr;
+  /**
+   * Length of the array, not counting the null-terminator
+   */
+  uintptr_t length;
+} ddog_CStr;
+
 #ifdef __cplusplus
 extern "C" {
 #endif // __cplusplus

Diff for: components-rs/common.h

@@ -21,6 +21,7 @@ use ddcommon::{parse_uri, Endpoint};
 use ddcommon_ffi::slice::AsBytes;
 pub use ddcommon_ffi::*;
 pub use ddtelemetry_ffi::*;
+pub use datadog_library_config_ffi::*;
 
 #[no_mangle]
 #[allow(non_upper_case_globals)]

Diff for: components-rs/lib.rs

@@ -0,0 +1,39 @@
+// Copyright 2021-Present Datadog, Inc. https://www.datadoghq.com/
+// SPDX-License-Identifier: Apache-2.0
+
+
+#ifndef DDOG_LIBRARY_CONFIG_H
+#define DDOG_LIBRARY_CONFIG_H
+
+#pragma once
+
+#include "common.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif // __cplusplus
+
+struct ddog_Configurator *ddog_library_configurator_new(bool debug_logs);
+
+void ddog_library_configurator_drop(struct ddog_Configurator*);
+
+struct ddog_Result_VecLibraryConfig ddog_library_configurator_get_path(const struct ddog_Configurator *configurator,
+                                                                       struct ddog_ProcessInfo process_info,
+                                                                       ddog_CharSlice path);
+
+struct ddog_Result_VecLibraryConfig ddog_library_configurator_get(const struct ddog_Configurator *configurator,
+                                                                  struct ddog_ProcessInfo process_info);
+
+struct ddog_Result_VecLibraryConfig ddog_library_configurator_get_from_bytes(const struct ddog_Configurator *configurator,
+                                                                             struct ddog_ProcessInfo process_info,
+                                                                             ddog_ByteSlice config_bytes);
+
+struct ddog_CStr ddog_library_config_name_to_env(enum ddog_LibraryConfigName name);
+
+void ddog_library_config_drop(struct ddog_Vec_LibraryConfig);
+
+#ifdef __cplusplus
+} // extern "C"
+#endif // __cplusplus
+
+#endif /* DDOG_LIBRARY_CONFIG_H */

Diff for: components-rs/library-config.h

@@ -1,12 +1,14 @@
 #include "configuration.h"
 
 #include <assert.h>
+#include <SAPI.h>
 
 #include "ip_extraction.h"
 #include "logging.h"
 #include "json/json.h"
 #include "sidecar.h"
 #include <components/log/log.h>
+#include <components-rs/library-config.h>
 #include <zai_string/string.h>
 #include "sidecar.h"
 
@@ -236,6 +238,43 @@ void ddtrace_config_first_rinit() {
     runtime_config_first_init = true;
 }
 
+// FIXME: where should it be done? minit? rinit? first rinit???
+void ddtrace_config_rinit() {
+    // FIXME: should be done directly in the library-config crate
+    ddog_CharSlice args[] = {
+        DDOG_CHARSLICE_C("/usr/bin/php"),
+    };
+
+    ddog_CharSlice envp[] = {
+        DDOG_CHARSLICE_C("FOO=BAR"),
+    };
+    ddog_ProcessInfo process_info = {
+        .args = args,
+        .envp = envp,
+        .language = DDOG_CHARSLICE_C("php")
+    };
+
+    ddog_Configurator *configurator = ddog_library_configurator_new(true);
+    ddog_Result_VecLibraryConfig config_result = ddog_library_configurator_get_path(configurator, process_info, DDOG_CHARSLICE_C("./config.yaml"));
+    // ddog_Result_VecLibraryConfig config_result = ddog_library_configurator_get(configurator, process_info);
+
+    if (config_result.tag != DDOG_RESULT_VEC_LIBRARY_CONFIG_ERR_VEC_LIBRARY_CONFIG) {
+        ddog_Vec_LibraryConfig configs = config_result.ok;
+        for (int i = 0; i < configs.len; i++) {
+            const ddog_LibraryConfig *cfg = &configs.ptr[i];
+            ddog_CStr name = ddog_library_config_name_to_env(cfg->name);
+
+            printf("Setting env variable: %s=%s\n", name.ptr, cfg->value.ptr);
+            setenv(name.ptr, cfg->value.ptr, 1);
+        }
+    } else {
+        // ddog_Error err = config_result.err;
+        // fprintf(stderr, "%.*s", (int)err.message.len, err.message.ptr);
+        // ddog_Error_drop(&err);
+    }
+}
+
+
 // note: only call this if get_DD_TRACE_ENABLED() returns true
 bool ddtrace_config_integration_enabled(ddtrace_integration_name integration_name) {
     ddtrace_integration *integration = &ddtrace_integrations[integration_name];