Install and Start Using the C SDK with Couchbase Server

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    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.

    Platform support and installation

    The Couchbase C SDK can be installed via apt or yum repositories on GNU/Linux; homebrew on Mac OS X; and binary archives for Microsoft Windows. It may also be built from source on any of the platforms mentioned above, and more.

    Installing on GNU/Linux

    The various Linux distributions contain the following packages:

    • libcouchbase3: The core library package.

    • libcouchbase-dev (or libcouchbase-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 and Linux quick start explains the steps it will perform on your distribution. To configure the repository:

    1. Find the appropriate repository location for your distribution in the following table.

    Version

    Architecture

    Repository

    Amazon Linux 2

    64-bit

    https://packages.couchbase.com/clients/c/repos/rpm/amzn2/x86_64

    Enterprise Linux 8

    64-bit

    https://packages.couchbase.com/clients/c/repos/rpm/el8/x86_64

    Enterprise Linux 7

    64-bit

    https://packages.couchbase.com/clients/c/repos/rpm/el7/x86_64

    1. 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

    Configuring APT repositories (Debian, Ubuntu)

    This section assumes some knowledge of apt and Linux quick start explains the steps it will perform on your distribution. To configure the repository:

    1. Download the Couchbase GPG key from https://packages.couchbase.com/clients/c/repos/deb/couchbase.key

    2. Add the key to the list of trusted package keys. Use the apt-key add command. For example, apt-key add couchbase.key.

    3. 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")

    deb https://packages.couchbase.com/clients/c/repos/deb/ubuntu1604 xenial xenial/main

    Ubuntu 18.04 ("bionic")

    deb https://packages.couchbase.com/clients/c/repos/deb/ubuntu1804 bionic bionic/main

    Ubuntu 20.04 ("focal")

    deb https://packages.couchbase.com/clients/c/repos/deb/ubuntu2004 focal focal/main

    Debian 9 ("stretch")

    deb https://packages.couchbase.com/clients/c/repos/deb/debian9 stretch stretch/main

    Debian 10 ("buster")

    deb https://packages.couchbase.com/clients/c/repos/deb/debian10 buster buster/main

    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-get update
    $ sudo apt-cache 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-get install libcouchbase3 libcouchbase-dev libcouchbase3-tools libcouchbase-dbg libcouchbase3-libev libcouchbase3-libevent

    For CentOS and Red Hat, the equivalent commands are:

    sudo yum check-update
    sudo yum search libcouchbase
    sudo yum install libcouchbase3 libcouchbase-devel libcouchbase3-tools

    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 on CentOS 8 box, see table below for other RPM-based distributions.

    $ curl -O https://packages.couchbase.com/clients/c/libcouchbase-3.0.0_centos8_x86_64.tar
    $ tar xf libcouchbase-3.0.0_centos8_x86_64.tar
    $ cd libcouchbase-3.0.0_centos8_x86_64
    $ sudo yum install -y libcouchbase3{-tools,-libevent,}-3.0.0*.rpm libcouchbase-devel-*.rpm
    > ...
    > Installed:
    >   libcouchbase3-tools-3.0.0-1.el8.x86_64
    >   libcouchbase3-libevent-3.0.0-1.el8.x86_64
    >   libcouchbase3-3.0.0-1.el8.x86_64
    >   libcouchbase-devel-3.0.0-1.el8.x86_64
    >
    > Complete!

    Installing DEBs

    The following commands show steps to execute on Debian 10 (buster) box, see table below for other DEB-based distributions.

    $ curl -O https://packages.couchbase.com/clients/c/libcouchbase-3.0.0_debian10_buster_amd64.tar
    $ tar xf libcouchbase-3.0.0_debian10_buster_amd64.tar
    $ cd libcouchbase-3.0.0_debian10_buster_amd64
    $ sudo apt install libevent-core-2.1
    $ sudo dpkg -i libcouchbase3{-tools,-libevent,}_3.0.0*.deb libcouchbase-dev*.deb
    > Selecting previously unselected package libcouchbase3-tools.
    > (Reading database ... 7165 files and directories currently installed.)
    > Preparing to unpack libcouchbase3-tools_3.0.0-1_amd64.deb ...
    > Unpacking libcouchbase3-tools (3.0.0-1) ...
    > Selecting previously unselected package libcouchbase3-libevent:amd64.
    > Preparing to unpack libcouchbase3-libevent_3.0.0-1_amd64.deb ...
    > Unpacking libcouchbase3-libevent:amd64 (3.0.0-1) ...
    > Selecting previously unselected package libcouchbase3:amd64.
    > Preparing to unpack libcouchbase3_3.0.0-1_amd64.deb ...
    > Unpacking libcouchbase3:amd64 (3.0.0-1) ...
    > Selecting previously unselected package libcouchbase-dev:amd64.
    > Preparing to unpack libcouchbase-dev_3.0.0-1_amd64.deb ...
    > Unpacking libcouchbase-dev:amd64 (3.0.0-1) ...
    > Setting up libcouchbase3:amd64 (3.0.0-1) ...
    > Setting up libcouchbase-dev:amd64 (3.0.0-1) ...
    > Setting up libcouchbase3-libevent:amd64 (3.0.0-1) ...
    > Setting up libcouchbase3-tools (3.0.0-1) ...
    > Processing triggers for libc-bin (2.28-10) ...

    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.

    Installation on Mac OS X

    To install the library on Mac OS X, first install the de-facto package manager for OS X: homebrew. Once homebrew is configured:

    $ brew update # get list of latest packages
    $ brew install libcouchbase

    Windows Installation

    Windows binary packages can be found as downloads for each version listed below. 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 (MSVCRT.DLL).

    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 3.0.0 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=3.0.0, Changeset=69f9a4eb8414f4bfd3824b863701d89a313401d5
      Headers: Version=3.0.0, Changeset=69f9a4eb8414f4bfd3824b863701d89a313401d5
      Build Timestamp: 2020-01-17 00:32:49
      Default plugin directory: /usr/lib64/libcouchbase
      IO: Default=libevent, Current=libevent, Accessible=libevent,select
      SSL Runtime: OpenSSL 1.1.1c FIPS  28 May 2019
      SSL Headers: OpenSSL 1.1.1c FIPS  28 May 2019
      Snappy: 1.1.1
      Tracing: SUPPORTED
      System: Linux-4.4.0-135-generic; x86_64
      CC: GNU 8.3.1; -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 8.3.1; -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

    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]));

    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 3.0 SDK is ready for the planned introduction of Collections in a future release of the Couchbase Data Platform. The latest release, 6.5 Beta, brings a limited Developer Preview of Collections, allowing Documents to be grouped by purpose or theme, according to specified Scope. Here we will use NULL for default collection, which covers the whole Bucket.

    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 *collection = NULL, *scope = NULL;
    size_t collection_len = 0, scope_len = 0;
    const char *key = "my-document";
    const char *value = "{\"name\": \"mike\"}";
    rc = lcb_cmdstore_create(&cmd, LCB_STORE_UPSERT);
    rc = lcb_cmdstore_collection(cmd, scope, scope_len, collection, collection_len);
    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 *collection = NULL, *scope = NULL;
    size_t collection_len = 0, scope_len = 0;
    const char *key = "my-document";
    rc = lcb_cmdget_create(&cmd);
    rc = lcb_cmdget_collection(cmd, scope, scope_len, collection, collection_len);
    rc = lcb_cmdget_key(cmd, key, strlen(key));
    rc = lcb_get(instance, NULL, cmd);
    rc = lcb_cmdget_destroy(cmd);
    rc = lcb_wait(instance);

    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.