Install and Start Using the C SDK with Couchbase Server
The Couchbase C SDK (libcouchbase - LCB) enables you to interact with a Couchbase Server cluster from the C language. It is also used by the Node.js, PHP, and Python SDKs to communicate with the Couchbase Server.
Installation from source
You may install the library from source either by downloading a source archive, or by checking out the git repository. Follow the instructions in the archive’s README for further instructions.
Installing on GNU/Linux
The various Linux distributions contain the following packages:
-
libcouchbase3
: The core library package. -
libcouchbase-dev
(orlibcouchbase-devel
): The development package, required if building SDKs which depend on the C SDK. -
libcouchbase3-tools
: The command line utilities (cbc
and others). -
libcouchbase3-libevent
: Optional but recommended component for I/O performance. Can also be used to integrate with libevent (see Asynchronous Programming). -
libcouchbase3-libev
: Optional, for use with applications that make use of event loop integration with libev (see Asynchronous Programming). To install the C SDK from a static binary package or by manually configuring the repositories, you can use the following procedures.
Configuring yum repositories (CentOS, Redhat)
This section assumes you know how to add an external yum repository. To configure the repository:
-
Find the appropriate repository location for your distribution in the following table.
Version
Architecture
Repository
Amazon Linux 2
aarch64
https://packages.couchbase.com/clients/c/repos/rpm/amzn2/aarch64
Amazon Linux 2
x86_64
https://packages.couchbase.com/clients/c/repos/rpm/amzn2/x86_64
Enterprise Linux 8
x86_64
https://packages.couchbase.com/clients/c/repos/rpm/el8/x86_64
Enterprise Linux 7
x86_64
https://packages.couchbase.com/clients/c/repos/rpm/el7/x86_64
-
Create a
couchbase.repo
file in your/etc/yum.repos.d
directory. It should look similar to the following:[couchbase] enabled = 1 name = libcouchbase package for centos8 x86_64 baseurl = https://packages.couchbase.com/clients/c/repos/rpm/el8/x86_64 gpgcheck = 1 gpgkey = https://packages.couchbase.com/clients/c/repos/rpm/couchbase.key
Now that you have the repository configured, refresh the cache then check to see that you have been successful:
$ sudo yum check-update
$ sudo yum search libcouchbase
Now, install libcouchbase3
, and any other packages that you need for development:
$ sudo yum install libcouchbase3 libcouchbase-devel libcouchbase3-tools
Configuring APT repositories (Debian, Ubuntu)
This section assumes some knowledge of apt. To configure the repository:
-
Download the Couchbase GPG key from https://packages.couchbase.com/clients/c/repos/deb/couchbase.key
-
Add the key to the list of trusted package keys. Use the
apt-key add
command. For example,apt-key add couchbase.key
. -
Create a couchbase.list file in
/etc/apt/sources.list.d
. The file should contain the repository for your distribution. Repositories are available for the following distributions:
Distribution |
Repository Entry |
Ubuntu 16.04 ("xenial") |
|
Ubuntu 18.04 ("bionic") |
|
Ubuntu 20.04 ("focal") |
|
Debian 9 ("stretch") |
|
Debian 10 ("buster") |
|
Debian 11 ("bullseye") |
|
Note that only Ubuntu LTS (long term support) releases are supported. You may try to use an LTS repository for a non-LTS version, but success is not guaranteed.
Now that you have the repository configured, refresh the cache then check to see that you have been successful:
$ sudo apt update
$ sudo apt search libcouchbase
You should see something like:
libcouchbase-dbg - library for the Couchbase protocol, debug symbols
libcouchbase-dev - library for the Couchbase protocol, development files
libcouchbase3 - library for the Couchbase protocol, core files
libcouchbase3-libev - library for the Couchbase protocol (libev backend)
libcouchbase3-libevent - library for the Couchbase protocol (libevent backend)
libcouchbase3-tools - library for the Couchbase protocol
Now, install libcouchbase3
, and any other packages that you need for development:
$ sudo apt install libcouchbase3 libcouchbase-dev libcouchbase3-tools libcouchbase-dbg libcouchbase3-libev libcouchbase3-libevent
Installing binary packages without a repository
You can install standalone packages by downloading a tarball containing the necessary binary packages for your platform.
Installing RPMs
The following commands show steps to execute for the current version on a CentOS 8 box. Check the Downloads table for other Redhat based systems.
$ curl -O https://packages.couchbase.com/clients/c/libcouchbase-3.2.1_centos8_x86_64.tar
$ tar xf libcouchbase-3.2.1_centos8_x86_64.tar
$ cd libcouchbase-3.2.1_centos8_x86_64
$ sudo yum install -y libcouchbase3{-tools,-libevent,}-3.2.1*.rpm libcouchbase-devel-*.rpm
> ...
> Installed:
> libcouchbase-devel-3.2.1-1.el8.x86_64
> libcouchbase3-3.2.1-1.el8.x86_64
> libcouchbase3-libevent-3.2.1-1.el8.x86_64
> libcouchbase3-tools-3.2.1-1.el8.x86_64
> ...
>
> Complete!
Installing DEBs
The following commands show steps to execute for the current version on a Debian 10 (buster) box. Check the Downloads table for the other DEB-based distributions.
$ curl -O https://packages.couchbase.com/clients/c/libcouchbase-3.2.1_debian10_buster_amd64.tar
$ tar xf libcouchbase-3.2.1_debian10_buster_amd64.tar
$ cd libcouchbase-3.2.1_debian10_buster_amd64
$ sudo apt install libevent-core-2.1
$ sudo dpkg -i libcouchbase3{-tools,-libevent,}_3.2.1*.deb libcouchbase-dev*.deb
> Selecting previously unselected package libcouchbase3-tools.
> (Reading database ... 7177 files and directories currently installed.)
> Preparing to unpack libcouchbase3-tools_3.2.1-1_amd64.deb ...
> Unpacking libcouchbase3-tools (3.2.1-1) ...
> Selecting previously unselected package libcouchbase3-libevent:amd64.
> Preparing to unpack libcouchbase3-libevent_3.2.1-1_amd64.deb ...
> Unpacking libcouchbase3-libevent:amd64 (3.2.1-1) ...
> Selecting previously unselected package libcouchbase3:amd64.
> Preparing to unpack libcouchbase3_3.2.1-1_amd64.deb ...
> Unpacking libcouchbase3:amd64 (3.2.1-1) ...
> Selecting previously unselected package libcouchbase-dev:amd64.
> Preparing to unpack libcouchbase-dev_3.2.1-1_amd64.deb ...
> Unpacking libcouchbase-dev:amd64 (3.2.1-1) ...
> Setting up libcouchbase3:amd64 (3.2.1-1) ...
> Setting up libcouchbase-dev:amd64 (3.2.1-1) ...
> Setting up libcouchbase3-libevent:amd64 (3.2.1-1) ...
> Setting up libcouchbase3-tools (3.2.1-1) ...
> Processing triggers for libc-bin (2.28-10) ...
Installation on Mac OS X
To install the latest version of the library on Mac OS X, first install the de-facto package manager for OS X: homebrew. Once homebrew is configured:
Get list of latest packages:
$ brew update
Install the latest version of libcouchbase
:
$ brew install libcouchbase
To install development files and command line tools on Mac OS, or to install an earlier version of the library, follow the instructions for installing from source.
Windows Installation
Windows binary packages can be found in the Downloads table for each supported version of libcouchbase.
Included are the header files, release and debug variants of the DLLs and import libraries, and release and debug variants of the command line tools.
Note that the C SDK does not have any preferred installation path, and it is up to you to determine where to place libcouchbase.dll
.
Be sure to select the proper package for the compiler and architecture your application is using.
If there are no binaries available for your Visual Studio version, then using a binary from any other Visual Studio version is likely to work.
Most of the issues related to mixing Visual Studio binary versions involve changing and incompatible C APIs or incompatible C Runtime (CRT) objects and functions.
Since the Couchbase C SDK does not expose a C API, and since it does not directly expose any CRT functionality, it should be safe for use so long as your application can link to the library at compile-time.
The windows runtime linker will ensure that each binary is using the appropriate version of the Visual C Runtime ( |
If for some reason you cannot use any of the prebuilt Windows binaries, follow the instructions in installation from source (above) to build on Windows.
Verifying Installed Package
The easiest way to verify installed package is to check its version using cbc tools. It requires package libcouchbase3-tools installed on Linux systems, for Windows cbc.exe included in the zip archive. To verify the client run cbc version (cbc.exe version on Windows). Below is the output from version 3.2.0 on CentOS 8. It shows version along with git commit numbers. Then it prints default directory where IO plugins installed and enumerates the currently installed and available plugins. After that it reports whether OpenSSL linked to this particular version of libcouchbase, and displays the version number if it is accessible.
$ cbc version
cbc:
Runtime: Version=3.2.0, Changeset=c712686af5825f2f05c89112e555cd09906aa727
Headers: Version=3.2.0, Changeset=c712686af5825f2f05c89112e555cd09906aa727
Build Timestamp: 2021-07-20 09:31:59
Default plugin directory: /usr/lib64/libcouchbase
IO: Default=libevent, Current=libevent, Accessible=libevent,select
SSL Runtime: OpenSSL 1.1.1g FIPS 21 Apr 2020
SSL Headers: OpenSSL 1.1.1g FIPS 21 Apr 2020
Snappy: 1.1.8
Tracing: SUPPORTED
System: Linux-4.15.0-91-generic; x86_64
CC: GNU 8.4.1; -O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -fno-strict-aliasing -ggdb3 -pthread
CXX: GNU 8.4.1; -O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -fno-strict-aliasing -ggdb3 -pthread
Documentation and Examples
-
Small standalone examples can be found in the github repository.
-
Other Couchbase SDKs are written on top of the C SDK and show more complex usage of the library’s features:
-
The library’s own
cbc
(https://github.com/couchbase/libcouchbase/blob/master/tools/cbc.cc) andcbc-pillowfight
(https://github.com/couchbase/libcouchbase/blob/master/tools/cbc-pillowfight.cc) utilities. Note that these tools may use internal APIs not intended for public use.
Hello Couchbase
Now you have the C client installed, you need to include the following in your first program:
lcb_CREATEOPTS *create_options = NULL;
lcb_createopts_create(&create_options, LCB_TYPE_CLUSTER);
lcb_createopts_connstr(create_options, argv[1], strlen(argv[1]));
// username, password
lcb_createopts_credentials(create_options, argv[2], strlen(argv[2]), argv[3], strlen(argv[3]));
If you are connecting to Couchbase Capella rather than a local Couchbase Server, see the Cloud section, below.
Couchbase uses Role Based Access Control (RBAC) to control access to resources. Here we will use the Full Admin role created during installation of the Couchbase Data Platform. For production client code, you will want to use more appropriate, restrictive settings, but here we want to get you up and running quickly. If you’re developing client code on the same VM or machine as the Couchbase Server, your URI can be localhost.
lcb_STATUS rc; /* return code, that have to be checked */
lcb_INSTANCE *instance;
rc = lcb_create(&instance, &create_options);
lcb_createopts_destroy(create_options);
rc = lcb_connect(instance);
rc = lcb_wait(instance);
rc = lcb_get_bootstrap_status(instance);
After initializing the cluster, we open a bucket:
static void open_callback(lcb_INSTANCE *instance, lcb_STATUS rc)
{
printf("open bucket: %s\n", lcb_strerror_short(rc));
}
// associate instance with a bucket
lcb_set_open_callback(instance, open_callback);
const char *name = "bucket-name";
rc = lcb_open(instance, name, strlen(name)),
If you installed the travel sample data bucket, substitute travel-sample for bucket-name.
The 3.x SDKs support full integration with the Collections feature in the latest release of Couchbase Server, 7.0.
This includes complete support of Collections, allowing Documents to be grouped by purpose or theme, according to a specified Scope.
Here we will use the users
collection within the tenant_agent_00
scope from travel-sample
bucket as an example.
static void store_callback(lcb_INSTANCE *instance, int cbtype, const lcb_RESPSTORE *resp)
{
const char *key;
size_t nkey;
uint64_t cas;
lcb_respstore_key(resp, &key, &nkey);
lcb_respstore_cas(resp, &cas);
printf("status: %s, key: %.*s, CAS: 0x%" PRIx64 "\n",
lcb_strerror_short(lcb_respstore_status(resp)), (int)nkey, key, cas);
}
lcb_install_callback3(instance, LCB_CALLBACK_STORE, (lcb_RESPCALLBACK)store_callback);
lcb_STATUS rc;
lcb_CMDSTORE *cmd;
const char *scope = "tenant_agent_00", *collection = "users";
const char *key = "my-document";
const char *value = "{\"name\": \"mike\"}";
rc = lcb_cmdstore_create(&cmd, LCB_STORE_UPSERT);
rc = lcb_cmdstore_collection(cmd, scope, strlen(scope), collection, strlen(collection));
rc = lcb_cmdstore_key(cmd, key, strlen(key));
rc = lcb_cmdstore_value(cmd, value, strlen(value));
rc = lcb_store(instance, NULL, cmd);
rc = lcb_cmdstore_destroy(cmd);
rc = lcb_wait(instance);
static void get_callback(lcb_INSTANCE *instance, int cbtype, const lcb_RESPGET *resp)
{
const char *key, *value;
size_t nkey, nvalue;
uint64_t cas;
lcb_respget_key(resp, &key, &nkey);
lcb_respget_value(resp, &value, &nvalue);
lcb_respget_cas(resp, &cas);
printf("status: %s, key: %.*s, CAS: 0x%" PRIx64 "\n",
lcb_strerror_short(lcb_respget_status(resp)), (int)nkey, key, cas);
printf("value:\n%s\n", (int)nvalue, value);
}
lcb_install_callback3(instance, LCB_CALLBACK_GET, (lcb_RESPCALLBACK)get_callback);
lcb_STATUS rc;
lcb_CMDGET *cmd;
const char *scope = "tenant_agent_00", *collection = "users";
const char *key = "my-document";
rc = lcb_cmdget_create(&cmd);
rc = lcb_cmdget_collection(cmd, scope, strlen(scope), collection, strlen(collection));
rc = lcb_cmdget_key(cmd, key, strlen(key));
rc = lcb_get(instance, NULL, cmd);
rc = lcb_cmdget_destroy(cmd);
rc = lcb_wait(instance);
This code shows how you would use a named collection and scope. A named or default collection will provide the same functionality as bucket-level operations did in previous versions of Couchbase Server.
Cloud Connections
For developing on Couchbase Capella, if you are not working from the same Availability Zone, refer to the following:
-
Notes on Constrained Network Environments,
-
If you have a consumer-grade router which has problems with DNS-SRV records review our Troubleshooting Guide.
Additional Resources
The API reference is generated for each release and the latest can be found here. Older API references are linked from their respective sections in the Release Notes.
Couchbase welcomes community contributions to the C SDK. The C SDK source code is available on GitHub.