Merge pull request #1265 from chu11/issue1193-part1

kvs: support append operation

doc/man1/flux-kvs.adoc

@@ -50,13 +50,15 @@ interpreted as encoded JSON and formatted accordingly.  If '-r', value
 is displayed without a newline.  If '-t', the RFC 11 object is displayed.
 '-a treeobj' causes the lookup to be relative to an RFC 11 snapshot reference.
 
-*put* [-j|-r|-t] [-n] 'key=value' ['key=value...']::
+*put* [-j|-r|-t] [-n] [-A] 'key=value' ['key=value...']::
 Store 'value' under 'key' and commit it.  If it already has a value,
 overwrite it.  If no options, value is stored directly.  If '-j', it is
 first encoded as JSON, then stored.  If '-r', the value may be read from
 standard input if specified as "-", and may include embedded NULL bytes.
 If '-t', value is stored as a RFC 11 object.  '-n' prevents the commit
-from being merged with with other contemporaneous commits.
+from being merged with with other contemporaneous commits.  '-A' appends the
+value to a key instead of overwriting the value.  Append is incompatible with
+the -j option.
 
 *ls* [-R] [-d] [-F] [-w COLS] [-1] ['key' ...]::
 Display directory referred to by _key_, or "." (root) if unspecified.

doc/man3/flux_kvs_txn_create.adoc

@@ -57,6 +57,7 @@ Each function below adds a single operation to _txn_.  _key_ is a
 hierarchical path name with period (".") used as path separator.
 When the transaction is committed, any existing keys or path components
 that are in conflict with the requested operation are overwritten.
+_flags_ can modify the request as described below.
 
 `flux_kvs_txn_put()` sets _key_ to a NULL terminated string _value_.
 _value_ may be NULL indicating that an empty value should be stored.
@@ -83,7 +84,12 @@ as a JSON string.
 FLAGS
 -----
 
-The _flags_ argument is currently unused and must be zero.
+The following are valid bits in a _flags_ mask passed as an argument
+to `flux_kvs_txn_put()` or `flux_kvs_txn_put_raw()`.
+
+FLUX_KVS_APPEND::
+Append value instead of overwriting it.  If the key does not exist,
+it will be created with the value as the initial value.
 
 
 include::JSON_PACK.adoc[]

src/cmd/flux-kvs.c

@@ -94,6 +94,9 @@ static struct optparse_option put_opts[] =  {
     { .name = "no-merge", .key = 'n', .has_arg = 0,
       .usage = "Set the NO_MERGE flag to ensure commit is standalone",
     },
+    { .name = "append", .key = 'A', .has_arg = 0,
+      .usage = "Append value(s) to key instead of overwriting",
+    },
     OPTPARSE_TABLE_END
 };
 
@@ -498,6 +501,7 @@ int cmd_put (optparse_t *p, int argc, char **argv)
     flux_future_t *f;
     flux_kvs_txn_t *txn;
     int commit_flags = 0;
+    int put_flags = 0;
 
     optindex = optparse_option_index (p);
     if ((optindex - argc) == 0) {
@@ -534,18 +538,25 @@ int cmd_put (optparse_t *p, int argc, char **argv)
         else if (optparse_hasopt (p, "raw")) {
             int len;
             uint8_t *buf = NULL;
+
+            if (optparse_hasopt (p, "append"))
+                put_flags |= FLUX_KVS_APPEND;
+
             if (!strcmp (val, "-")) { // special handling for "--raw key=-"
                 if ((len = read_all (STDIN_FILENO, &buf)) < 0)
                     log_err_exit ("stdin");
                 val = (char *)buf;
             } else
                 len = strlen (val);
-            if (flux_kvs_txn_put_raw (txn, 0, key, val, len) < 0)
+            if (flux_kvs_txn_put_raw (txn, put_flags, key, val, len) < 0)
                 log_err_exit ("%s", key);
             free (buf);
         }
         else {
-            if (flux_kvs_txn_put (txn, 0, key, val) < 0)
+            if (optparse_hasopt (p, "append"))
+                put_flags |= FLUX_KVS_APPEND;
+
+            if (flux_kvs_txn_put (txn, put_flags, key, val) < 0)
                 log_err_exit ("%s", key);
         }
         free (key);

src/common/libkvs/kvs.h

@@ -18,6 +18,7 @@ enum {
     FLUX_KVS_READDIR = 1,
     FLUX_KVS_READLINK = 2,
     FLUX_KVS_TREEOBJ = 16,
+    FLUX_KVS_APPEND = 32,
 };
 
 /* Synchronization:

src/common/libkvs/kvs_txn.c

@@ -122,7 +122,7 @@ int flux_kvs_txn_put_raw (flux_kvs_txn_t *txn, int flags,
         errno = EINVAL;
         goto error;
     }
-    if (validate_flags (flags, 0) < 0)
+    if (validate_flags (flags, FLUX_KVS_APPEND) < 0)
         goto error;
     if (!(dirent = treeobj_create_val (data, len)))
         goto error;
@@ -174,7 +174,7 @@ int flux_kvs_txn_put (flux_kvs_txn_t *txn, int flags,
         errno = EINVAL;
         goto error;
     }
-    if (validate_flags (flags, 0) < 0)
+    if (validate_flags (flags, FLUX_KVS_APPEND) < 0)
         goto error;
     if (!(dirent = treeobj_create_val (value, value ? strlen (value) : 0)))
         goto error;
@@ -373,11 +373,13 @@ int txn_encode_op (const char *key, int flags, json_t *dirent, json_t **opp)
 {
     json_t *op;
 
-    if (!key || strlen (key) == 0 || flags != 0 || !dirent
+    if (!key || strlen (key) == 0 || !dirent
              || (!json_is_null (dirent) && treeobj_validate (dirent) < 0)) {
         errno = EINVAL;
         return -1;
     }
+    if (validate_flags (flags, FLUX_KVS_APPEND) < 0)
+        return -1;
     if (!(op = json_pack ("{s:s s:i s:O}",
                           "key", key,
                           "flags", flags,

src/common/libkvs/test/kvs_txn.c

@@ -317,13 +317,30 @@ void test_raw_values (void)
     flux_kvs_txn_destroy (txn);
 }
 
+void test_corner_cases (void)
+{
+    json_t *val;
+    json_t *op;
+
+    ok (txn_encode_op (NULL, 0, NULL, NULL) < 0 && errno == EINVAL,
+        "txn_encode_op fails on bad input");
+
+    val = treeobj_create_val ("abcd", 4);
+
+    ok (txn_encode_op ("key", 0x44, val, &op) < 0 && errno == EINVAL,
+        "txn_encode_op fails on bad flags");
+
+    json_decref (val);
+}
+
 int main (int argc, char *argv[])
 {
 
     plan (NO_PLAN);
 
     basic ();
     test_raw_values ();
+    test_corner_cases ();
 
     done_testing();
     return (0);