[rrd-developers] [PATCH 2/4] src/rrd_client.[ch]: Add `rrdc_fetch'.

Florian Forster rrdtool at nospam.verplant.org
Tue Mar 24 16:40:14 CET 2009


From: Florian Forster <octo at leeloo.lan.home.verplant.org>

The `rrdc_fetch' command has the same interface as `rrd_fetch_r' and
behaves just like it, except that it will read the value from the RRD
caching daemon, using the `FETCH' command.

Signed-off-by: Florian Forster <octo at leeloo.lan.home.verplant.org>
---
 src/rrd_client.c |  340 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
 src/rrd_client.h |   10 ++-
 2 files changed, 348 insertions(+), 2 deletions(-)

diff --git a/src/rrd_client.c b/src/rrd_client.c
index 8e60664..602a1ee 100644
--- a/src/rrd_client.c
+++ b/src/rrd_client.c
@@ -1,6 +1,6 @@
 /**
  * RRDTool - src/rrd_client.c
- * Copyright (C) 2008 Florian octo Forster
+ * Copyright (C) 2008,2009  Florian octo Forster
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the
@@ -51,6 +51,137 @@ static int sd = -1;
 static FILE *sh = NULL;
 static char *sd_path = NULL; /* cache the path for sd */
 
+static size_t strsplit (char *string, char **fields, size_t size) /* {{{ */
+{
+  size_t i;
+  char *ptr;
+  char *saveptr;
+
+  i = 0;
+  ptr = string;
+  saveptr = NULL;
+  while ((fields[i] = strtok_r (ptr, " \t\r\n", &saveptr)) != NULL)
+  {
+    ptr = NULL;
+    i++;
+
+    if (i >= size)
+      break;
+  }
+
+  return (i);
+} /* }}} size_t strsplit */
+
+static int parse_header (char *line, /* {{{ */
+    char **ret_key, char **ret_value)
+{
+  char *tmp;
+
+  *ret_key = line;
+
+  tmp = strchr (line, ':');
+  if (tmp == NULL)
+    return (-1);
+
+  do
+  {
+    *tmp = 0;
+    tmp++;
+  }
+  while ((tmp[0] == ' ') || (tmp[0] == '\t'));
+
+  if (*tmp == 0)
+    return (-1);
+
+  *ret_value = tmp;
+  return (0);
+} /* }}} int parse_header */
+
+static int parse_ulong_header (char *line, /* {{{ */
+    char **ret_key, unsigned long *ret_value)
+{
+  char *str_value;
+  char *endptr;
+  int status;
+
+  str_value = NULL;
+  status = parse_header (line, ret_key, &str_value);
+  if (status != 0)
+    return (status);
+
+  endptr = NULL;
+  errno = 0;
+  *ret_value = (unsigned long) strtol (str_value, &endptr, /* base = */ 0);
+  if ((endptr == str_value) || (errno != 0))
+    return (-1);
+
+  return (0);
+} /* }}} int parse_ulong_header */
+
+static int parse_char_array_header (char *line, /* {{{ */
+    char **ret_key, char **array, size_t array_len, int alloc)
+{
+  char *tmp_array[array_len];
+  char *value;
+  size_t num;
+  int status;
+
+  value = NULL;
+  status = parse_header (line, ret_key, &value);
+  if (status != 0)
+    return (-1);
+
+  num = strsplit (value, tmp_array, array_len);
+  if (num != array_len)
+    return (-1);
+
+  if (alloc == 0)
+  {
+    memcpy (array, tmp_array, sizeof (tmp_array));
+  }
+  else
+  {
+    size_t i;
+
+    for (i = 0; i < array_len; i++)
+      array[i] = strdup (tmp_array[i]);
+  }
+
+  return (0);
+} /* }}} int parse_char_array_header */
+
+static int parse_value_array_header (char *line, /* {{{ */
+    time_t *ret_time, rrd_value_t *array, size_t array_len)
+{
+  char *str_key;
+  char *str_array[array_len];
+  char *endptr;
+  int status;
+  size_t i;
+
+  str_key = NULL;
+  status = parse_char_array_header (line, &str_key,
+      str_array, array_len, /* alloc = */ 0);
+  if (status != 0)
+    return (-1);
+
+  errno = 0;
+  endptr = NULL;
+  *ret_time = (time_t) strtol (str_key, &endptr, /* base = */ 10);
+  if ((endptr == str_key) || (errno != 0))
+    return (-1);
+
+  for (i = 0; i < array_len; i++)
+  {
+    endptr = NULL;
+    array[i] = (rrd_value_t) strtod (str_array[i], &endptr);
+    if ((endptr == str_array[i]) || (errno != 0))
+      return (-1);
+  }
+
+  return (0);
+} /* }}} int parse_value_array_header */
+
 /* One must hold `lock' when calling `close_connection'. */
 static void close_connection (void) /* {{{ */
 {
@@ -604,6 +735,213 @@ int rrdc_flush (const char *filename) /* {{{ */
   return (status);
 } /* }}} int rrdc_flush */
 
+int rrdc_fetch (const char *filename, /* {{{ */
+    const char *cf,
+    time_t *ret_start, time_t *ret_end,
+    unsigned long *ret_step,
+    unsigned long *ret_ds_num,
+    char ***ret_ds_names,
+    rrd_value_t **ret_data)
+{
+  char buffer[4096];
+  char *buffer_ptr;
+  size_t buffer_free;
+  size_t buffer_size;
+  rrdc_response_t *res;
+  char file_path[PATH_MAX];
+
+  char *str_tmp;
+  unsigned long flush_version;
+
+  time_t start;
+  time_t end;
+  unsigned long step;
+  unsigned long ds_num;
+  char **ds_names;
+
+  rrd_value_t *data;
+  size_t data_size;
+  size_t data_fill;
+
+  int status;
+  size_t current_line;
+  time_t t;
+
+  if ((filename == NULL) || (cf == NULL))
+    return (-1);
+
+  /* Send request {{{ */
+  memset (buffer, 0, sizeof (buffer));
+  buffer_ptr = &buffer[0];
+  buffer_free = sizeof (buffer);
+
+  status = buffer_add_string ("FETCH", &buffer_ptr, &buffer_free);
+  if (status != 0)
+    return (ENOBUFS);
+
+  /* change to absolute path for rrdcached */
+  if (*filename != '/' && realpath(filename, file_path) != NULL)
+      filename = file_path;
+
+  status = buffer_add_string (filename, &buffer_ptr, &buffer_free);
+  if (status != 0)
+    return (ENOBUFS);
+
+  status = buffer_add_string (cf, &buffer_ptr, &buffer_free);
+  if (status != 0)
+    return (ENOBUFS);
+
+  if ((ret_start != NULL) && (*ret_start > 0))
+  {
+    char tmp[64];
+    snprintf (tmp, sizeof (tmp), "%lu", (unsigned long) *ret_start);
+    tmp[sizeof (tmp) - 1] = 0;
+    status = buffer_add_string (tmp, &buffer_ptr, &buffer_free);
+    if (status != 0)
+      return (ENOBUFS);
+
+    if ((ret_end != NULL) && (*ret_end > 0))
+    {
+      snprintf (tmp, sizeof (tmp), "%lu", (unsigned long) *ret_end);
+      tmp[sizeof (tmp) - 1] = 0;
+      status = buffer_add_string (tmp, &buffer_ptr, &buffer_free);
+      if (status != 0)
+        return (ENOBUFS);
+    }
+  }
+
+  assert (buffer_free < sizeof (buffer));
+  buffer_size = sizeof (buffer) - buffer_free;
+  assert (buffer[buffer_size - 1] == ' ');
+  buffer[buffer_size - 1] = '\n';
+
+  res = NULL;
+  status = request (buffer, buffer_size, &res);
+  if (status != 0)
+    return (status);
+
+  status = res->status;
+  if (status < 0)
+  {
+    rrd_set_error ("rrdcached: %s", res->message);
+    response_free (res);
+    return (status);
+  }
+  /* }}} Send request */
+
+  ds_names = NULL;
+  ds_num = 0;
+  data = NULL;
+  current_line = 0;
+
+  /* Macros to make error handling a little easier (i. e. less to type and
+   * read. `BAIL_OUT' sets the error message, frees all dynamically allocated
+   * variables and returns the provided status code. */
+#define BAIL_OUT(status, ...) do { \
+    rrd_set_error ("rrdc_fetch: " __VA_ARGS__); \
+    free (data); \
+    if (ds_names != 0) { size_t k; for (k = 0; k < ds_num; k++) free (ds_names[k]); } \
+    free (ds_names); \
+    response_free (res); \
+    return (status); \
+  } while (0)
+
+#define READ_NUMERIC_FIELD(name,type,var) do { \
+    char *key; \
+    unsigned long value; \
+    assert (current_line < res->lines_num); \
+    status = parse_ulong_header (res->lines[current_line], &key, &value); \
+    if (status != 0) \
+      BAIL_OUT (-1, "Unable to parse header `%s'", name); \
+    if (strcasecmp (key, name) != 0) \
+      BAIL_OUT (-1, "Unexpected header line: Expected `%s', got `%s'", name, key); \
+    var = (type) value; \
+    current_line++; \
+  } while (0)
+
+  if (res->lines_num < 1)
+    BAIL_OUT (-1, "Premature end of response packet");
+
+  /* We're making some very strong assumptions about the fields below. We
+   * therefore check the version of the `flush' command first, so that later
+   * versions can change the order of fields and it's easier to implement
+   * backwards compatibility. */
+  READ_NUMERIC_FIELD ("FlushVersion", unsigned long, flush_version);
+  if (flush_version != 1)
+    BAIL_OUT (-1, "Don't know how to handle flush format version %lu.",
+        flush_version);
+
+  if (res->lines_num < 5)
+    BAIL_OUT (-1, "Premature end of response packet");
+
+  READ_NUMERIC_FIELD ("Start", time_t, start);
+  READ_NUMERIC_FIELD ("End", time_t, end);
+  if (start >= end)
+    BAIL_OUT (-1, "Malformed start and end times: start = %lu; end = %lu;",
+        (unsigned long) start,
+        (unsigned long) end);
+
+  READ_NUMERIC_FIELD ("Step", unsigned long, step);
+  if (step < 1)
+    BAIL_OUT (-1, "Invalid number for Step: %lu", step);
+
+  READ_NUMERIC_FIELD ("DSCount", unsigned long, ds_num);
+  if (ds_num < 1)
+    BAIL_OUT (-1, "Invalid number for DSCount: %lu", ds_num);
+  
+  /* It's time to allocate some memory */
+  ds_names = calloc ((size_t) ds_num, sizeof (*ds_names));
+  if (ds_names == NULL)
+    BAIL_OUT (-1, "Out of memory");
+
+  status = parse_char_array_header (res->lines[current_line],
+      &str_tmp, ds_names, (size_t) ds_num, /* alloc = */ 1);
+  if (status != 0)
+    BAIL_OUT (-1, "Unable to parse header `DSName'");
+  if (strcasecmp ("DSName", str_tmp) != 0)
+    BAIL_OUT (-1, "Unexpected header line: Expected `DSName', got `%s'", str_tmp);
+  current_line++;
+
+  data_size = ds_num * (end - start) / step;
+  if (data_size < 1)
+    BAIL_OUT (-1, "No data returned or headers invalid.");
+
+  if (res->lines_num != (6 + (data_size / ds_num)))
+    BAIL_OUT (-1, "Got %zu lines, expected %zu",
+        res->lines_num, (6 + (data_size / ds_num)));
+
+  data = calloc (data_size, sizeof (*data));
+  if (data == NULL)
+    BAIL_OUT (-1, "Out of memory");
+  
+
+  data_fill = 0;
+  for (t = start + step; t <= end; t += step, current_line++)
+  {
+    time_t tmp;
+
+    assert (current_line < res->lines_num);
+
+    status = parse_value_array_header (res->lines[current_line],
+        &tmp, data + data_fill, (size_t) ds_num);
+    if (status != 0)
+      BAIL_OUT (-1, "Cannot parse value line");
+
+    data_fill += (size_t) ds_num;
+  }
+
+  *ret_start = start;
+  *ret_end = end;
+  *ret_step = step;
+  *ret_ds_num = ds_num;
+  *ret_ds_names = ds_names;
+  *ret_data = data;
+
+  response_free (res);
+  return (0);
+#undef READ_NUMERIC_FIELD
+#undef BAIL_OUT
+} /* }}} int rrdc_flush */
 
 /* convenience function; if there is a daemon specified, or if we can
  * detect one from the environment, then flush the file.  Otherwise, no-op
diff --git a/src/rrd_client.h b/src/rrd_client.h
index 90b78f8..9f58af6 100644
--- a/src/rrd_client.h
+++ b/src/rrd_client.h
@@ -1,6 +1,6 @@
 /**
  * RRDTool - src/rrd_client.h
- * Copyright (C) 2008 Florian octo Forster
+ * Copyright (C) 2008,2009  Florian octo Forster
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the
@@ -58,6 +58,14 @@ int rrdc_update (const char *filename, int values_num,
 int rrdc_flush (const char *filename);
 int rrdc_flush_if_daemon (const char *opt_daemon, const char *filename);
 
+int rrdc_fetch (const char *filename,
+    const char *cf,
+    time_t *ret_start, time_t *ret_end,
+    unsigned long *ret_step,
+    unsigned long *ret_ds_num,
+    char ***ret_ds_names,
+    rrd_value_t **ret_data);
+
 #else
 #	define rrdc_flush_if_daemon(a,b) 0
 #	define rrdc_connect(a) 0
-- 
1.6.2



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