CP-18271 first cut at C library for RRD plugins

This PR implements the C library for writing RRD plugins. It has been tested using the code in the repository and against the rrd-transport library. A strange bug currently remains: the rrd-transport installed via yum (`ocaml-rrd-transport-devel`) reports a problem whereas an rrd-transport library compiled from source code does not.

.gitignore

@@ -0,0 +1,9 @@
+*.[ch]~
+rrdclient
+rrdtest
+ocaml/_build
+ocaml/rrdreader.native
+*.o
+*.a
+*.rrd
+

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "parson"]
+	path = parson
+	url = https://github.com/kgabis/parson.git

.travis.yml

@@ -0,0 +1,14 @@
+
+language: c
+sudo: false
+
+matrix:
+  include:
+    - compiler: gcc
+      os: linux
+
+script:
+  - make parson
+  - make
+  - make test
+

LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2016 Citrix
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

Makefile

@@ -0,0 +1,99 @@
+# vim: set ts=8 sw=8 noet:
+#
+#
+
+CC	= gcc
+CFLAGS	= -std=gnu99 -g -Wall
+OBJ	+= librrd.o
+OBJ 	+= parson/parson.o
+LIB     += -lz
+
+OCB 	= ocamlbuild -use-ocamlfind
+
+.PHONY: all
+all:	librrd.a rrdtest rrdclient
+
+.PHONY: clean
+clean:
+	rm -f $(OBJ)
+	rm -f librrd.a
+	rm -f librrd.o
+	rm -f parson/parson.o
+	rm -f rrdtest.o rrdtest
+	rm -f rrdclient.o rrdclient
+	rm -rf config.xml cov-int html coverity.out
+	cd ocaml;  $(OCB) -clean
+
+.PHONY: test
+test: 	rrdtest rrdclient
+	./rrdtest
+	seq 1 10 | ./rrdclient rrdclient.rrd
+	seq 1 10 \
+		| while read i; do echo $$i; sleep 1; done \
+		| ./rrdclient rrdclient.rrd
+
+.PHONY: valgrind
+valgrind: rrdtest
+	valgrind --leak-check=yes ./rrdtest
+	seq 1 10 | valgrind --leak-check=yes ./rrdclient rrdclient.rrd
+
+.PHONY: indent
+indent: librrd.h librrd.c rrdtest.c
+	indent -orig -nut $^
+
+.PHONY: depend
+depend: librrd.c rrdtest.c
+	$(CC) -MM $^
+
+.PHONY: parson
+parson:
+	# git submodule add https://github.com/kgabis/parson.git
+	git submodule init
+	git submodule update
+
+%.o:	%.c
+	$(CC) $(CFLAGS) -c -o $@ $<
+
+librrd.a: $(OBJ)
+	ar rc $@ $(OBJ)
+	ranlib $@
+
+rrdtest: rrdtest.o librrd.a
+	$(CC) $(CFLAGS) -o $@ $^ $(LIB)
+
+rrdclient: rrdclient.o librrd.a
+	$(CC) $(CFLAGS) -o $@ $^ $(LIB)
+
+# coverity analysis
+
+COV_OPTS += --cpp
+COV_OPTS += --aggressiveness-level high
+COV_OPTS += --all
+COV_OPTS += --rule
+COV_OPTS += --disable-parse-warnings
+COV_OPTS += --enable-fnptr
+
+COV_DIR = cov-int
+
+cov: 	parson
+	cov-configure --gcc --config config.xml
+	cov-build --dir $(COV_DIR)  --config config.xml $(MAKE)
+	cov-analyze $(COV_OPTS) --dir $(COV_DIR) --config config.xml
+	cov-format-errors --dir $(COV_DIR)  --emacs-style > coverity.out
+	cov-format-errors --dir $(COV_DIR) --html-output html
+
+# C dependencies
+
+parson/parson.h: 	parson
+parson/parson.c: 	parson
+
+parson/parson.o: 	parson/parson.h
+rrdtest.o: 		parson/parson.h librrd.h
+librrd.o: 		parson/parson.h librrd.h
+
+# OCaml test utility
+# You need: yum install -y ocaml-rrd-transport-devel
+
+rrdreader:
+	cd ocaml; $(OCB) -pkg rrd-transport -tag thread rrdreader.native
+

README.md

@@ -1,4 +1,6 @@
 
+[![Build Status](https://travis-ci.org/lindig/rrd-client-lib-1.svg?branch=master)](https://travis-ci.org/lindig/rrd-client-lib-1)
+
 # rrd-client-lib - A Library to Provide RRD Data
 
 The RRD service is a system-level service that aggregates
@@ -19,26 +21,27 @@ needs to be initialised:
 
     make parson
     make
-
+
+    make test
     ./rrdtest
 
 ## Parson
 
-The [Parson](https://github.com/kgabis/parson.git) library is included
-as a Git submodule. A submodule points to a specific commit in an
-external repository and does not track its master branch as this
+The JSON library [Parson](https://github.com/kgabis/parson.git) is
+included as a Git submodule. A submodule points to a specific commit in
+an external repository and does not track its master branch as this
 advances. Instead, it needs to be updated explicitly.
 
 ## Documentation - Overview
 
 The header file `librrd.h` contains the essential information to use the
 library:
 
-    typedef ...     rrd_value;
+    typedef ...     rrd_value_t;
     typedef ...     RRD_SOURCE;
     typedef ...     RRD_PLUGIN;
 
-    RRD_PLUGIN     *rrd_open(char *name, rrd_domain domain, char *path);
+    RRD_PLUGIN     *rrd_open(char *name, rrd_domain_t domain, char *path);
     int             rrd_close(RRD_PLUGIN * plugin);
     int             rrd_add_src(RRD_PLUGIN * plugin, RRD_SOURCE * source);
     int             rrd_del_src(RRD_PLUGIN * plugin, RRD_SOURCE * source);
@@ -55,6 +58,20 @@ samples values from all data sources and writes the data to the `path`
 provided to `rrd_open`. It is the client's responsibility to call
 `rrd_sample` regularly at an interval of 5 seconds.
 
+## Sample Code
+
+See `rrdclient.c` for a simple client that reads integers from standard
+input as a data source and reports them to RRD. Here is how everything
+is compiled and linked:
+
+    gcc -std=gnu99 -g -Wall -c -o librrd.o librrd.c
+    gcc -std=gnu99 -g -Wall -c -o parson/parson.o parson/parson.c
+    ar rc librrd.a librrd.o parson/parson.o
+    ranlib librrd.a
+    gcc -std=gnu99 -g -Wall -c -o rrdclient.o rrdclient.c
+    gcc -std=gnu99 -g -Wall -o rrdclient rrdclient.o librrd.a -lz
+
+
 ## Interface
 
     <<librrd.h>>=
@@ -78,11 +95,15 @@ A plugin opens a file for communication and periodically calls
 considered private to the library.
 
     <<type definitions>>=
-    typedef enum { RRD_LOCAL_DOMAIN = 0, RRD_INTER_DOMAIN } rrd_domain;
+    /* rrd_domain_t */
+    typedef int32_t rrd_domain_t;
+    #define RRD_LOCAL_DOMAIN        0
+    #define RRD_INTER_DOMAIN        1
+
 
 
     <<function declarations>>=
-    RRD_PLUGIN     *rrd_open(char *name, rrd_domain domain, char *path);
+    RRD_PLUGIN     *rrd_open(char *name, rrd_domain_t domain, char *path);
     int             rrd_close(RRD_PLUGIN * plugin);
     int             rrd_sample(RRD_PLUGIN * plugin);
 
@@ -98,32 +119,44 @@ integer or float values. Data sources can be added and removed
 dynamically.
 
     <<type definitions>>=
-    typedef enum { RRD_GAUGE = 0, RRD_ABSOLUTE, RRD_DERIVE } rrd_scale;
-    typedef enum { RRD_HOST = 0, RRD_VM, RRD_SR } rrd_owner;
-    typedef enum { RRD_FLOAT64 = 0, RRD_INT64 } rrd_type;
+    /* rrd_scale_t */
+    typedef int32_t rrd_scale_t;
+    #define RRD_GAUGE               0
+    #define RRD_ABSOLUTE            1
+    #define RRD_DERIVE              2
+
+    /* rrd_owner_t */
+    typedef int32_t rrd_owner_t;
+    #define RRD_HOST                0
+    #define RRD_VM                  1
+    #define RRD_SR                  2
+
+    /* rrd_type_t */
+    typedef int32_t rrd_type_t;
+    #define RRD_FLOAT64             0
+    #define RRD_INT64               1
 
     typedef union {
         int64_t         int64;
-        float           float64;
-    } rrd_value;
+        double          float64;
+    } rrd_value_t;
 
     typedef struct rrd_source {
         char           *name;       /* name of the data source */
         char           *description;        /* for user interface */
-        rrd_owner       owner;
-        int             rrd_default;/* true: rrd daemon will archive */
         char           *owner_uuid; /* UUID of the owner or NULL */
         char           *rrd_units;  /* for user interface */
-        rrd_scale       scale;      /* presentation of value */
-        rrd_type        type;       /* type of value */
         char           *min;        /* min <= sample() <= max */
         char           *max;        /* min <= sample() <= max */
-                        rrd_value(*sample) (void);  /* reads value that gets *
-                                                     * reported */
+                        rrd_value_t(*sample) (void);  /* reads value */
+        rrd_owner_t     owner;
+        int32_t         rrd_default;        /* true: rrd daemon will archive */
+        rrd_scale_t     scale;      /* presentation of value */
+        rrd_type_t      type;       /* type of value */
     } RRD_SOURCE;
 
+    typedef struct rrd_plugin RRD_PLUGIN;
 
-    <<typedef RRD_PLUGIN>>
 
     <<function declarations>>=
     int rrd_add_src(RRD_PLUGIN *plugin, RRD_SOURCE *source);
@@ -135,7 +168,7 @@ reporting. It includes a function (pointer) `sample` that obtains the
 value being reported. A value can be either a 64-bit integer or a 64-bit
 floating point value -- discriminated by `type`.
 
-## Error Handling
+## Constants and Error Handling
 
 Some functions return an error code.
 
@@ -149,26 +182,6 @@ Some functions return an error code.
     #define RRD_ERROR               4
 
 
-
-## Private Types
-
-    <<constants>>=
-    #define RRD_MAX_SOURCES           128
-
-
-    <<typedef RRD_PLUGIN>>=
-    typedef struct rrd_plugin {
-        char           *name;       /* name of the plugin */
-        int             file;       /* where we report data */
-        rrd_domain      domain;     /* domain of this plugin */
-        RRD_SOURCE     *sources[RRD_MAX_SOURCES];
-        uint32_t        n;          /* number of used slots */
-        JSON_Value     *meta;       /* meta data for the plugin */
-        char           *buf;        /* buffer where we keep protocol data */
-        size_t          buf_size;   /* size of the buffer */
-    } RRD_PLUGIN;
-
-
 ## Design
 
 The library updates the file provided to `rrd_open` when `rrd_sample` is