REFACTOR: refactor config file support for server configuration

arcus.conf

@@ -0,0 +1,155 @@
+# ============================================================
+# Arcus-memcached Configuration File
+#
+# This file is used to configure the Arcus-memcached server at startup.
+#
+# Usage:
+#   ./memcached -c arcus.conf
+#   ./memcached -c arcus.conf -p 20000 (CLI options override config file settings)
+#
+# Format:
+#   key=value
+#   Lines starting with '#' are treated as comments.
+# ============================================================
+
+
+# [Required] Path to the storage engine library (.so).
+# This must be specified to start the server.
+engine_path=.libs/default_engine.so
+
+# TCP port number to listen on. (Default: 11211)
+port=11211
+
+# UDP port number to listen on. (Default: 0)
+# udpport=0
+
+# The IP address of the network interface to listen on.
+# 0.0.0.0 means listen on all available interfaces (INADDR_ANY).
+listen=0.0.0.0
+
+# Path to the UNIX socket file.
+# socketpath=/tmp/memcached.sock
+
+# Access mask for the UNIX socket in octal. (Default: 0700)
+# access=0700
+
+# Assume the identity of <username> (drops root privileges).
+# Effectively switches the user after starting.
+# username=nobody
+
+# Number of worker threads to process incoming requests. (Default: 4)
+# Typically set to the number of CPU cores.
+threads=4
+
+# Maximum number of simultaneous connections. (Default: 1024)
+# Connections exceeding this limit may be queued or rejected.
+maxconns=1024
+
+# Backlog queue limit for pending connections. (Default: 1024)
+backlog=1024
+
+# Maximum number of requests per event. (Default: 20)
+# Limits the number of requests processed for a given connection to prevent starvation.
+reqs_per_event=20
+
+# Maximum memory to use for item storage. (Default: 64)
+memory_limit=64M
+
+# Maximum size of a single item. (Default: 1m)
+# Supports K and M suffixes. Min: 1k, Max: 128m.
+# Adjusting this value also adjusts the slab page size.
+item_size_max=1m
+
+# Action to take when memory is exhausted. (Default: false)
+# false = Evict old items (LRU) to make space.
+# true  = Return an error instead of evicting items.
+eviction=false
+
+# Chunk size growth factor between slab classes. (Default: 1.25)
+# Controls the size increase of chunks in subsequent slab classes.
+factor=1.25
+
+# Minimum space allocated for key+value+flags. (Default: 48)
+chunk_size=48
+
+# Sticky (gummed) memory limit in MB. (Default: 0 - Unlimited)
+# Reserved memory for items that should not be evicted.
+sticky_limit=0
+
+# Use large memory pages if available. (Default: false)
+# Can improve performance by reducing TLB misses.
+preallocate=false
+
+# These options control the behavior of the Arcus storage engine,
+# including Collection features (List, Set, Map, B+Tree).
+
+# Enable CAS (Check-And-Set) feature. (Default: true)
+# Ensures data consistency. Set to false to disable.
+use_cas=true
+
+# Raw configuration string passed directly to the engine.
+# Format: param1=val1;param2=val2...
+# engine_config=conf/default_engine.conf
+
+# Character to use as a delimiter for key prefixes in stats. (Default: :)
+# If specified, per-prefix stats collection is automatically enabled.
+prefix_delimiter=:
+
+# Enable detailed stats collection. (Default: false)
+# Automatically enabled if 'prefix_delimiter' is set.
+detail_enabled=false
+
+# Allow the 'stats detail' command to be used. (Default: true)
+allow_detailed=true
+
+# Run as a daemon (background process). (Default: false)
+daemonize=false
+
+# File to write the Process ID (PID) to when running as a daemon.
+# pid_file=/var/run/memcached.pid
+
+# Verbose logging level. (Default: 3)
+# 0 = Detail, 1 = Debug, 2 = Info, 3 = Warning
+# Higher values result in less logging.
+verbosity=3
+
+# Limit the size of the core file. (Default: 0)
+# Used for debugging purposes to allow core dumps.
+maxcore=0
+
+# Lock down all paged memory. (Default: false)
+# Prevents memory from being swapped out, but may fail if system limit is exceeded.
+lock_memory=false
+
+# Path to the UNIX socket file (if used).
+# socketpath=/tmp/memcached.sock
+
+# Access mask for the UNIX socket in octal. (Default: 0700)
+# access=0700
+
+# Protocol to use (auto, binary, ascii). (Default: auto)
+protocol=auto
+
+# Load extension libraries (.so).
+# Used to load additional modules like loggers or management tools.
+# extension1=/usr/local/lib/logger.so
+# extension2=/usr/local/lib/management.so
+
+# Settings required
+
+# ZooKeeper ensemble server list.
+# Only available if compiled with ZooKeepr support.
+# Format: host1:port1,host2:port2,...
+# zookeeper=zk1.local:2181,zk2.local:2181,zk3.local:2181
+
+# ZooKeeper session timeout in milliseconds. (Default: 0 -> Uses internal default)
+# Only available if compiled with ZooKeepr support.
+# Recommended value: > 10 and < 20000 (check internal implementation limits).
+# zk_timeout=3000
+
+# Proxy configuration (if compiled with proxy support)
+# proxy_config=...
+
+# Require SASL authentication for connections. (Default: false)
+# Only available if compiled with SASL support.
+# require_sasl=false

config_parser.c

@@ -26,9 +26,6 @@
 #include <memcached/config_parser.h>
 #include <memcached/util.h>
 
-static int read_config_file(const char *fname, struct config_item items[],
-                            FILE *error);
-
 /**
  * Copy a string and trim of leading and trailing white space characters.
  * Allow the user to escape out the stop character by putting a backslash before
@@ -224,8 +221,7 @@ int parse_config(const char *str, struct config_item *items, FILE *error) {
    return ret;
 }
 
-static int read_config_file(const char *fname, struct config_item items[],
-                            FILE *error) {
+int read_config_file(const char *fname, struct config_item items[], FILE *error) {
    FILE *fp = fopen(fname, "r");
    if (fp == NULL) {
       (void)fprintf(error, "Failed to open file: %s\n", fname);

include/memcached/config_parser.h

@@ -77,6 +77,7 @@ struct config_item {
  */
 MEMCACHED_PUBLIC_API int parse_config(const char *str, struct config_item items[], FILE *error);
 
+int read_config_file(const char *fname, struct config_item items[], FILE *error);
 #ifdef __cplusplus
 }
 #endif