Allow `.WithMetadata` function to use pact DSL rather than static values

[nsfrias]

Software versions

• OS: Mac OSX 12.3.1
• Consumer Pact library: v2.0.0-beta.11
• Provider Pact library: v2.0.0-beta.11
• Golang Version: go version go1.18.3 darwin/arm6
• Golang environment:

GO111MODULE=""
GOARCH="arm64"
GOBIN=""
GOCACHE="/Users/nunofrias/Library/Caches/go-build"
GOENV="/Users/nunofrias/Library/Application Support/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="arm64"
GOHOSTOS="darwin"
GOINSECURE=""
GOMODCACHE="/Users/nunofrias/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/nunofrias/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/opt/homebrew/Cellar/go/1.18.3/libexec"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/opt/homebrew/Cellar/go/1.18.3/libexec/pkg/tool/darwin_arm64"
GOVCS=""
GOVERSION="go1.18.3"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/Users/nunofrias/Documents/repos/reseller-entitlement-service/go.mod"
GOWORK=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -arch arm64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/zn/48yhvjqd17z0x_qy9y6bqn080000gn/T/go-build3642680703=/tmp/go-build -gno-record-gcc-switches -fno-common"

Expected behaviour

WithMetadata method of github.com/pact-foundation/pact-go/v2/message should accept Pact DSL as argument (something like map[string]Matcher similarly to WithJSONContent) to allow us to set an expectation for metadata properties that are not static -- for example a timestamp.

Actual behaviour

WithMetadata method of github.com/pact-foundation/pact-go/v2/message only accepts a map[string]string thus allowing us to define only static metadata properties.

[nsfrias]

Working on this.

[nsfrias]

Hi,

After some investigation I found that the pact_ffi rust library needs to be changed to allow metadata to include matchers, the changes that need to happen in my view are:

• change the pactffi_message_with_metadata function (in pact_ffi/src/mock_server/handles.rs)to include the metadata rules in the Pact matchingRules section
• change the pactffi_message_reify function (in pact_ffi/src/mock_server/handles.rs) to reify the metadata values (right now it only handles the contents)

In addition to this a very minor change is required in WithMetadata function in pact-go/internal/native/message_server.go to build the matching rule (using stringFromInterface()).

The rust changes will take me a bit as I am yet not very familiar with it. :(