add go tutorial

docs/tutorials/go.md

@@ -0,0 +1,72 @@
+# Packaging a Go package
+
+This tutorial will guide you through making a Go package with `rattler-build`.
+
+When building a recipe for Go, most Go dependencies are linked statically. That means, we should collect their licenses and add them in the package. The `go-licenses` tool can help you with this task - as shown in the example below.
+
+## The different Go compilers
+
+The `conda-forge` ecosystem provides two go compilers: `go-cgo` and `go-nocgo`.
+
+By default, if you do not need to link against C libraries, it's recommended to use the `go-nocgo` compiler.
+It generates fat binaries without libc dependencies. The compiler activation scripts will set your `CC`, `CXX` and related flags to invalid values.
+
+The `go-cgo` compiler can generate fat binaries that depend on conda-forge's libc. You should use this compiler if the underlying program needs to link against other C libraries, in which case make sure to add `${{ compiler('c') }}` (`cxx`, `fortran`, ...) for unix and the `m2w64` equivalent for windows.
+
+## Example Go recipe
+
+This example shows how to package the [Temporal CLI](https://github.com/temporalio/cli).
+
+```yaml title="recipe.yaml"
+context:
+    version: "0.13.1"
+
+package:
+  name: temporal
+  version: ${{ version }}
+
+source:
+  url: https://github.com/temporalio/cli/archive/refs/tags/v${{ version }}.tar.gz
+  sha256: 9d8812c96d3404490659fec3915dcd23c4142b421ef4cb7e9622bd9a459e1f74
+
+build:
+  number: 0
+
+requirements:
+  build:
+    - ${{ compiler('go-nocgo') }}
+    - go-licenses
+
+tests:
+  - script:
+      - temporal --version
+
+about:
+  homepage: https://temporal.io
+  repository: https://github.com/temporalio/cli
+  documentation: https://docs.temporal.io/cli
+  summary: Temporal CLI
+  description: |
+    Command-line interface for running Temporal Server and interacting with
+    Workflows, Activities, Namespaces, and other parts of Temporal.
+  license: MIT
+  license_file:
+    - LICENSE
+    # These license files are generated at build time in the `build.sh` script
+    # from all the dependencies of `temporal.io`.
+    - license-files/
+```
+
+The build script (on Unix) should look something like this:
+
+```sh title="build.sh"
+# The LDFLAGS are used to set the version of the `temporal` binary. This is a common practice in Go.
+export LDFLAGS="${LDFLAGS} -s -w -X github.com/temporalio/cli/temporalcli.Version=${PKG_VERSION}"
+
+# Build the `temporal` binary and store it in the `$PREFIX/bin` directory.
+go build -ldflags "$LDFLAGS" -o $PREFIX/bin/temporal ./cmd/temporal
+
+# Store the license files in a separate directory in the $SRC_DIR. These are embedded in the package
+# in the `license_file` section.
+go-licenses save ./cmd/temporal --save_path="$SRC_DIR/license-files/" || true
+```