vmod-flagship

Flagship module for Varnish

Author:	Guillaume Jacquart(@guillaumejacquart)
Date:	2022/11/30
Version:	0.1
Support Varnish Version:	6.6 ~ 7.x

SYNOPSIS

import flagship;

DESCRIPTION

Flagship vmod provide feature flagging & experimentation abilities at the web server level and cache server.

SHARED OBJECT

The shared object libflagship_linux_amd64.so is generated from Flagship Go SDK using Go wrapper for C. Repository Link

FUNCTIONS

init

Prototype

init(
        STRING envID,           // [your env id]
        STRING apiKey,          // [your api key]
        INT pollingInterval,    // [polling interval]
        STRING logLevel,        // [log level]
        INT trackingEnabled     // [tracking enabled]
)

Return value

VOID

Description

Initialize flagship.

Example

::

import flagship;

sub vcl_init {

flagship.init("FS_ENV_ID", "FS_API_KEY", 200, "debug", 0);

}

compute_flags

Prototype

compute_flags(
        STRING visitorID,       // [your visitor id]
        STRING context         // [your context]
)

Return value

STRING

Description

Return flags that corresponds to the visitor id and context (flags are separated by ";").

Example

::

sub vcl_hash {

set req.http.X-FS-FLAGVALUES = flagship.compute_flags("visitor_id", "visitor_context");

}

get_flag_bool

Prototype

get_flag_bool(
        STRING visitorID,       // [your visitor id]
        STRING context,         // [your context]
        STRING key,             // [your flag key]
        INT defaultValue,       // [default value]
        INT activate            // [activate]
)

Return value

INT

Description

Return flag that corresponds to the visitor id and context.

Example

::

sub vcl_hash {

set req.http.X-FS-FLAGBOOL = flagship.get_flag_bool("visitor_id", "visitor_context", "flag_key", 0, 0);

}

get_flag_string

Prototype

get_flag_string(
        STRING visitorID,       // [your visitor id]
        STRING context,         // [your context]
        STRING key,             // [your flag key]
        STRING defaultValue,    // [default value]
        INT activate            // [activate]
)

Return value

STRING

Description

Return flag that corresponds to the visitor id and context.

Example

::

sub vcl_hash {

set req.http.X-FS-FLAGSTRING = flagship.get_flag_string("visitor_id", "visitor_context", "flag_key", "default_value", 0);

}

get_flag_number

Prototype

get_flag_number(
        STRING visitorID,       // [your visitor id]
        STRING context,         // [your context]
        STRING key,             // [your flag key]
        INT defaultValue,       // [default value]
        INT activate            // [activate]
)

Return value

STRING

Description

Return flag that corresponds to the visitor id and context.

Example

::

sub vcl_hash {

set req.http.X-FS-FLAGNUMBER = flagship.get_flag_string("visitor_id", "visitor_context", "flag_key", 12.0, 0);

}

INSTALLATION

Before installating make sure to copy the file libflagship_linux_amd64.so to /usr/lib/ and the file libflagship_linux_amd64.h to /usr/include/

The source tree is based on autotools to configure the building, and does also have the necessary bits in place to do functional unit tests using the varnishtest tool.

Building requires the Varnish header files and uses pkg-config to find the necessary paths.

Usage:

./autogen.sh
./configure

If you have installed Varnish to a non-standard directory, call autogen.sh and configure with PKG_CONFIG_PATH pointing to the appropriate path. For instance, when varnishd configure was called with --prefix=$PREFIX, use

export PKG_CONFIG_PATH=${PREFIX}/lib/pkgconfig
export ACLOCAL_PATH=${PREFIX}/share/aclocal

The module will inherit its prefix from Varnish, unless you specify a different --prefix when running the configure script for this module.

Make targets:

• make - builds the vmod.
• make install - installs your vmod.
• make check - runs the unit tests in src/tests/*.vtc.
• make distcheck - run check and prepare a tarball of the vmod.

If you build a dist tarball, you don't need any of the autotools or pkg-config. You can build the module simply by running:

./configure
make

Installation directories

By default, the vmod configure script installs the built vmod in the directory relevant to the prefix. The vmod installation directory can be overridden by passing the vmoddir variable to make install.

COMMON PROBLEMS

• configure: error: Need varnish.m4 -- see README.rst

  Check whether PKG_CONFIG_PATH and ACLOCAL_PATH were set correctly before calling autogen.sh and configure

• Incompatibilities with different Varnish Cache versions

  Make sure you build this vmod against its correspondent Varnish Cache version. For instance, to build against Varnish Cache 4.1, this vmod must be built from branch 4.1.

COPYRIGHT

This document is licensed under the same license as the libvmod-flagship project. See LICENSE for details.

• Copyright (c) 2020-2022 AB Tasty

Shared objects and libraries based on the Flagship Go wrapper for C

• Copyright (c) 2022 AB Tasty AS
• https://github.com/flagship-io/flagship-c-go-wrapper
• https://github.com/flagship-io/flagship-c-go-wrapper/blob/main/LICENSE

File layout and configuration based on libvmod-example

• Copyright (c) 2011 Varnish Software AS
• https://github.com/varnishcache/libvmod-example/
• https://github.com/varnishcache/libvmod-example/blob/master/LICENSE