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Posted to dev@zookeeper.apache.org by SimplyFox <gi...@git.apache.org> on 2017/03/10 12:57:18 UTC
[GitHub] zookeeper pull request #189: ZOOKEEPER-169: Content needed: "Connecting to Z...
GitHub user SimplyFox opened a pull request:
https://github.com/apache/zookeeper/pull/189
ZOOKEEPER-169: Content needed: "Connecting to ZooKeeper"
Added a simply example in C++ to demonstrate Client connecting to
Zookeeper server using C bindings along with few lines of explanation.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/SimplyFox/zookeeper ZOOKEEPER-169
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/zookeeper/pull/189.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #189
----
commit e2cd20b6794d6ef432606faa7ccab0dd95970933
Author: Michelle <ph...@gmail.com>
Date: 2017-03-10T12:16:17Z
ZOOKEEPER-169: Content needed: "Connecting to ZooKeeper"
Added a simply example in C++ to demonstrate Client connecting to
Zookeeper server using C bindings along with few lines of explanation.
----
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[GitHub] zookeeper issue #189: ZOOKEEPER-169: Content needed: "Connecting to ZooKeepe...
Posted by SimplyFox <gi...@git.apache.org>.
Github user SimplyFox commented on the issue:
https://github.com/apache/zookeeper/pull/189
Hi @afine ,
Ok, that makes sense.
I'll change it to C. Is the example ok?
Thanks,
Michelle
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[GitHub] zookeeper pull request #189: ZOOKEEPER-169: Content needed: "Connecting to Z...
Posted by asfgit <gi...@git.apache.org>.
Github user asfgit closed the pull request at:
https://github.com/apache/zookeeper/pull/189
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[GitHub] zookeeper pull request #189: ZOOKEEPER-169: Content needed: "Connecting to Z...
Posted by SimplyFox <gi...@git.apache.org>.
Github user SimplyFox commented on a diff in the pull request:
https://github.com/apache/zookeeper/pull/189#discussion_r105862680
--- Diff: src/docs/src/documentation/content/xdocs/zookeeperProgrammers.xml ---
@@ -1714,7 +1714,115 @@ public abstract class ServerAuthenticationProvider implements AuthenticationProv
<section id="sc_connectingToZk">
<title>Connecting to ZooKeeper</title>
- <para></para>
+ <para>Before we begin, you will have to set up a running Zookeeper server so that we can start developing the client. For C client bindings, we will be using the multithreaded library(zookeeper_mt) with a simple example written in C. To establish a connection with Zookeeper server, we make use of C API - <emphasis>zookeeper_init</emphasis> with the following signature:</para>
+
+ <programlisting><emphasis>int</emphasis> <emphasis>zookeeper_init</emphasis>(<emphasis>const</emphasis> <emphasis>char</emphasis> *host, watcher_fn fn, <emphasis>int</emphasis> recv_timeout, <emphasis>const</emphasis> clientid_t *clientid, <emphasis>void</emphasis> *context, <emphasis>int</emphasis> flags);</programlisting>
+
+ <variablelist>
+ <varlistentry>
+ <term>*host</term>
+ <listitem>
+ <para>Connection string to zookeeper server in the format of host:port. If there are multiple servers, use comma as separator after specifying the host:port pairs. Eg: "127.0.0.1:2181,127.0.0.1:3001,127.0.0.1:3002"</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>fn</term>
+ <listitem>
+ <para>Watcher function to process events when a notification is triggered.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>recv_timeout</term>
+ <listitem>
+ <para>Session expiration time in milliseconds.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>*clientid</term>
+ <listitem>
+ <para>We can specify 0 for a new session. If a session has already establish previously, we could provide that client ID and it would reconnect to that previous session.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>*context</term>
+ <listitem>
+ <para>Context object that can be associated with the zkhandle_t handler. If it is not used, we can set it to 0.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>flags</term>
+ <listitem>
+ <para>In an initiation, we can leave it for 0.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+
+ <para>We will demonstrate client that outputs "Connected to Zookeeper" after successful connection or an error message otherwise. Let's call the following code <emphasis>zkClient.cc</emphasis> :</para>
+ <programlisting>
+#include <stdio.h>
+#include <zookeeper/zookeeper.h>
+#include <errno.h>
+using namespace std;
+
+// Keeping track of the connection state
+static int connected = 0;
+static int expired = 0;
+
+// *zkHandler handles the connection with Zookeeper
+static zhandle_t *zkHandler;
+
+// watcher function would process events
+void watcher(zhandle_t *zkH, int type, int state, const char *path, void *watcherCtx)
+{
+ if (type == ZOO_SESSION_EVENT) {
+
+ // state refers to states of zookeeper connection.
+ // To keep it simple, we would demonstrate these 3: ZOO_EXPIRED_SESSION_STATE, ZOO_CONNECTED_STATE, ZOO_NOTCONNECTED_STATE
+ // If you are using ACL, you should be aware of an authentication failure state - ZOO_AUTH_FAILED_STATE
+ if (state == ZOO_CONNECTED_STATE) {
+ connected = 1;
+ } else if (state == ZOO_NOTCONNECTED_STATE ) {
+ connected = 0;
+ } else if (state == ZOO_EXPIRED_SESSION_STATE) {
+ expired = 1;
+ connected = 0;
+ zookeeper_close(zkH);
+ }
+ }
+}
+
+int main(){
+ zoo_set_debug_level(ZOO_LOG_LEVEL_DEBUG);
+
+ // zookeeper_init returns the handler upon a successful connection, null otherwise
+ zkHandler = zookeeper_init("localhost:2181", watcher, 10000, 0, 0, 0);
+
+ if (!zkHandler) {
+ return errno;
+ }else{
+ printf("Connection established with Zookeeper. \n");
+ }
+
+ // Close Zookeeper connection
+ zookeeper_close(zkHandler);
+
+ return 0;
+}
+ </programlisting>
+
+ <para>Compile the code with the multithreaded library mentioned before.</para>
+ <para><command>> g++ -Iinclude/ zkClient.cpp -lzookeeper_mt -o Client</command></para>
--- End diff --
Will change it to C compiler.
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[GitHub] zookeeper pull request #189: ZOOKEEPER-169: Content needed: "Connecting to Z...
Posted by SimplyFox <gi...@git.apache.org>.
Github user SimplyFox commented on a diff in the pull request:
https://github.com/apache/zookeeper/pull/189#discussion_r105990456
--- Diff: src/docs/src/documentation/content/xdocs/zookeeperProgrammers.xml ---
@@ -1714,7 +1714,115 @@ public abstract class ServerAuthenticationProvider implements AuthenticationProv
<section id="sc_connectingToZk">
<title>Connecting to ZooKeeper</title>
- <para></para>
+ <para>Before we begin, you will have to set up a running Zookeeper server so that we can start developing the client. For C client bindings, we will be using the multithreaded library(zookeeper_mt) with a simple example written in C. To establish a connection with Zookeeper server, we make use of C API - <emphasis>zookeeper_init</emphasis> with the following signature:</para>
+
+ <programlisting><emphasis>int</emphasis> <emphasis>zookeeper_init</emphasis>(<emphasis>const</emphasis> <emphasis>char</emphasis> *host, watcher_fn fn, <emphasis>int</emphasis> recv_timeout, <emphasis>const</emphasis> clientid_t *clientid, <emphasis>void</emphasis> *context, <emphasis>int</emphasis> flags);</programlisting>
+
+ <variablelist>
+ <varlistentry>
+ <term>*host</term>
+ <listitem>
+ <para>Connection string to zookeeper server in the format of host:port. If there are multiple servers, use comma as separator after specifying the host:port pairs. Eg: "127.0.0.1:2181,127.0.0.1:3001,127.0.0.1:3002"</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>fn</term>
+ <listitem>
+ <para>Watcher function to process events when a notification is triggered.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>recv_timeout</term>
+ <listitem>
+ <para>Session expiration time in milliseconds.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>*clientid</term>
+ <listitem>
+ <para>We can specify 0 for a new session. If a session has already establish previously, we could provide that client ID and it would reconnect to that previous session.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>*context</term>
+ <listitem>
+ <para>Context object that can be associated with the zkhandle_t handler. If it is not used, we can set it to 0.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>flags</term>
+ <listitem>
+ <para>In an initiation, we can leave it for 0.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+
+ <para>We will demonstrate client that outputs "Connected to Zookeeper" after successful connection or an error message otherwise. Let's call the following code <emphasis>zkClient.cc</emphasis> :</para>
+ <programlisting>
+#include <stdio.h>
+#include <zookeeper/zookeeper.h>
+#include <errno.h>
+using namespace std;
+
+// Keeping track of the connection state
+static int connected = 0;
+static int expired = 0;
+
+// *zkHandler handles the connection with Zookeeper
+static zhandle_t *zkHandler;
+
+// watcher function would process events
+void watcher(zhandle_t *zkH, int type, int state, const char *path, void *watcherCtx)
+{
+ if (type == ZOO_SESSION_EVENT) {
+
+ // state refers to states of zookeeper connection.
+ // To keep it simple, we would demonstrate these 3: ZOO_EXPIRED_SESSION_STATE, ZOO_CONNECTED_STATE, ZOO_NOTCONNECTED_STATE
+ // If you are using ACL, you should be aware of an authentication failure state - ZOO_AUTH_FAILED_STATE
+ if (state == ZOO_CONNECTED_STATE) {
+ connected = 1;
+ } else if (state == ZOO_NOTCONNECTED_STATE ) {
+ connected = 0;
+ } else if (state == ZOO_EXPIRED_SESSION_STATE) {
+ expired = 1;
+ connected = 0;
+ zookeeper_close(zkH);
+ }
+ }
+}
+
+int main(){
+ zoo_set_debug_level(ZOO_LOG_LEVEL_DEBUG);
+
+ // zookeeper_init returns the handler upon a successful connection, null otherwise
+ zkHandler = zookeeper_init("localhost:2181", watcher, 10000, 0, 0, 0);
+
+ if (!zkHandler) {
+ return errno;
+ }else{
+ printf("Connection established with Zookeeper. \n");
+ }
+
+ // Close Zookeeper connection
+ zookeeper_close(zkHandler);
+
+ return 0;
+}
+ </programlisting>
+
+ <para>Compile the code with the multithreaded library mentioned before.</para>
+ <para><command>> g++ -Iinclude/ zkClient.cpp -lzookeeper_mt -o Client</command></para>
--- End diff --
Btw, I tested the code, and zoo_init doesn't seem to validate the port number. Given an invalid hostname, the zkhandler wont initialize. But given a wrong port number, it'd still work. Should I report it as a bug? or just specify in the documentation that a valid zookeeper port should be given?
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[GitHub] zookeeper pull request #189: ZOOKEEPER-169: Content needed: "Connecting to Z...
Posted by afine <gi...@git.apache.org>.
Github user afine commented on a diff in the pull request:
https://github.com/apache/zookeeper/pull/189#discussion_r106760299
--- Diff: src/docs/src/documentation/content/xdocs/zookeeperProgrammers.xml ---
@@ -1714,7 +1714,115 @@ public abstract class ServerAuthenticationProvider implements AuthenticationProv
<section id="sc_connectingToZk">
<title>Connecting to ZooKeeper</title>
- <para></para>
+ <para>Before we begin, you will have to set up a running Zookeeper server so that we can start developing the client. For C client bindings, we will be using the multithreaded library(zookeeper_mt) with a simple example written in C. To establish a connection with Zookeeper server, we make use of C API - <emphasis>zookeeper_init</emphasis> with the following signature:</para>
+
+ <programlisting><emphasis>int</emphasis> <emphasis>zookeeper_init</emphasis>(<emphasis>const</emphasis> <emphasis>char</emphasis> *host, watcher_fn fn, <emphasis>int</emphasis> recv_timeout, <emphasis>const</emphasis> clientid_t *clientid, <emphasis>void</emphasis> *context, <emphasis>int</emphasis> flags);</programlisting>
+
+ <variablelist>
+ <varlistentry>
+ <term>*host</term>
+ <listitem>
+ <para>Connection string to zookeeper server in the format of host:port. If there are multiple servers, use comma as separator after specifying the host:port pairs. Eg: "127.0.0.1:2181,127.0.0.1:3001,127.0.0.1:3002"</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>fn</term>
+ <listitem>
+ <para>Watcher function to process events when a notification is triggered.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>recv_timeout</term>
+ <listitem>
+ <para>Session expiration time in milliseconds.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>*clientid</term>
+ <listitem>
+ <para>We can specify 0 for a new session. If a session has already establish previously, we could provide that client ID and it would reconnect to that previous session.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>*context</term>
+ <listitem>
+ <para>Context object that can be associated with the zkhandle_t handler. If it is not used, we can set it to 0.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>flags</term>
+ <listitem>
+ <para>In an initiation, we can leave it for 0.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+
+ <para>We will demonstrate client that outputs "Connected to Zookeeper" after successful connection or an error message otherwise. Let's call the following code <emphasis>zkClient.cc</emphasis> :</para>
+ <programlisting>
+#include <stdio.h>
+#include <zookeeper/zookeeper.h>
+#include <errno.h>
+using namespace std;
+
+// Keeping track of the connection state
+static int connected = 0;
+static int expired = 0;
+
+// *zkHandler handles the connection with Zookeeper
+static zhandle_t *zkHandler;
+
+// watcher function would process events
+void watcher(zhandle_t *zkH, int type, int state, const char *path, void *watcherCtx)
+{
+ if (type == ZOO_SESSION_EVENT) {
+
+ // state refers to states of zookeeper connection.
+ // To keep it simple, we would demonstrate these 3: ZOO_EXPIRED_SESSION_STATE, ZOO_CONNECTED_STATE, ZOO_NOTCONNECTED_STATE
+ // If you are using ACL, you should be aware of an authentication failure state - ZOO_AUTH_FAILED_STATE
+ if (state == ZOO_CONNECTED_STATE) {
+ connected = 1;
+ } else if (state == ZOO_NOTCONNECTED_STATE ) {
+ connected = 0;
+ } else if (state == ZOO_EXPIRED_SESSION_STATE) {
+ expired = 1;
+ connected = 0;
+ zookeeper_close(zkH);
+ }
+ }
+}
+
+int main(){
+ zoo_set_debug_level(ZOO_LOG_LEVEL_DEBUG);
+
+ // zookeeper_init returns the handler upon a successful connection, null otherwise
+ zkHandler = zookeeper_init("localhost:2181", watcher, 10000, 0, 0, 0);
+
+ if (!zkHandler) {
+ return errno;
+ }else{
+ printf("Connection established with Zookeeper. \n");
+ }
+
+ // Close Zookeeper connection
+ zookeeper_close(zkHandler);
+
+ return 0;
+}
+ </programlisting>
+
+ <para>Compile the code with the multithreaded library mentioned before.</para>
+ <para><command>> g++ -Iinclude/ zkClient.cpp -lzookeeper_mt -o Client</command></para>
--- End diff --
I would file a JIRA for that so we can make the best decision there.
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[GitHub] zookeeper pull request #189: ZOOKEEPER-169: Content needed: "Connecting to Z...
Posted by afine <gi...@git.apache.org>.
Github user afine commented on a diff in the pull request:
https://github.com/apache/zookeeper/pull/189#discussion_r105765768
--- Diff: src/docs/src/documentation/content/xdocs/zookeeperProgrammers.xml ---
@@ -1714,7 +1714,115 @@ public abstract class ServerAuthenticationProvider implements AuthenticationProv
<section id="sc_connectingToZk">
<title>Connecting to ZooKeeper</title>
- <para></para>
+ <para>Before we begin, you will have to set up a running Zookeeper server so that we can start developing the client. For C client bindings, we will be using the multithreaded library(zookeeper_mt) with a simple example written in C. To establish a connection with Zookeeper server, we make use of C API - <emphasis>zookeeper_init</emphasis> with the following signature:</para>
+
+ <programlisting><emphasis>int</emphasis> <emphasis>zookeeper_init</emphasis>(<emphasis>const</emphasis> <emphasis>char</emphasis> *host, watcher_fn fn, <emphasis>int</emphasis> recv_timeout, <emphasis>const</emphasis> clientid_t *clientid, <emphasis>void</emphasis> *context, <emphasis>int</emphasis> flags);</programlisting>
+
+ <variablelist>
+ <varlistentry>
+ <term>*host</term>
+ <listitem>
+ <para>Connection string to zookeeper server in the format of host:port. If there are multiple servers, use comma as separator after specifying the host:port pairs. Eg: "127.0.0.1:2181,127.0.0.1:3001,127.0.0.1:3002"</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>fn</term>
+ <listitem>
+ <para>Watcher function to process events when a notification is triggered.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>recv_timeout</term>
+ <listitem>
+ <para>Session expiration time in milliseconds.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>*clientid</term>
+ <listitem>
+ <para>We can specify 0 for a new session. If a session has already establish previously, we could provide that client ID and it would reconnect to that previous session.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>*context</term>
+ <listitem>
+ <para>Context object that can be associated with the zkhandle_t handler. If it is not used, we can set it to 0.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>flags</term>
+ <listitem>
+ <para>In an initiation, we can leave it for 0.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+
+ <para>We will demonstrate client that outputs "Connected to Zookeeper" after successful connection or an error message otherwise. Let's call the following code <emphasis>zkClient.cc</emphasis> :</para>
+ <programlisting>
+#include <stdio.h>
+#include <zookeeper/zookeeper.h>
+#include <errno.h>
+using namespace std;
+
+// Keeping track of the connection state
+static int connected = 0;
+static int expired = 0;
+
+// *zkHandler handles the connection with Zookeeper
+static zhandle_t *zkHandler;
+
+// watcher function would process events
+void watcher(zhandle_t *zkH, int type, int state, const char *path, void *watcherCtx)
+{
+ if (type == ZOO_SESSION_EVENT) {
+
+ // state refers to states of zookeeper connection.
+ // To keep it simple, we would demonstrate these 3: ZOO_EXPIRED_SESSION_STATE, ZOO_CONNECTED_STATE, ZOO_NOTCONNECTED_STATE
+ // If you are using ACL, you should be aware of an authentication failure state - ZOO_AUTH_FAILED_STATE
+ if (state == ZOO_CONNECTED_STATE) {
+ connected = 1;
+ } else if (state == ZOO_NOTCONNECTED_STATE ) {
+ connected = 0;
+ } else if (state == ZOO_EXPIRED_SESSION_STATE) {
+ expired = 1;
+ connected = 0;
+ zookeeper_close(zkH);
+ }
+ }
+}
+
+int main(){
+ zoo_set_debug_level(ZOO_LOG_LEVEL_DEBUG);
+
+ // zookeeper_init returns the handler upon a successful connection, null otherwise
+ zkHandler = zookeeper_init("localhost:2181", watcher, 10000, 0, 0, 0);
+
+ if (!zkHandler) {
+ return errno;
+ }else{
+ printf("Connection established with Zookeeper. \n");
+ }
+
+ // Close Zookeeper connection
+ zookeeper_close(zkHandler);
+
+ return 0;
+}
+ </programlisting>
+
+ <para>Compile the code with the multithreaded library mentioned before.</para>
+ <para><command>> g++ -Iinclude/ zkClient.cpp -lzookeeper_mt -o Client</command></para>
--- End diff --
can we use a c compiler for consistency?
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