feat: the languagecontainer module to share data and functions with language containers

all_test.go

@@ -37,6 +37,8 @@ var noHeaderRequiredFiles = []string{
 	".gitignore",
 	"Dockerfile",
 	"LICENSE",
+	"languagecontainer/go.mod",
+	"languagecontainer/go.sum",
 	"coverage.out",
 	"go.mod",
 	"go.sum",

languagecontainer/bazel/parser.go

@@ -0,0 +1,19 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//	https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package bazel provides functions to parse Bazel-related files.
+package bazel
+
+// TODO: Implement this package. Reference https://github.com/googleapis/google-cloud-go/tree/main/internal/librariangen/bazel
+// and Mike's porting for Java.

languagecontainer/cmd/cmd.go

@@ -0,0 +1,84 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//	https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package cmd provides the main function LanguageContainerMain that
+// handles command line argument parsing and invocation of the corresponding methods.
+package cmd
+
+import (
+	"context"
+)
+
+// GenerateFlags is the flags in Librarian's container contract for the
+// generate command. Each value represents the path of the context, such as
+// "/librarian", in which the CLI and the language container exchange
+// generate-request.json and generate-response.json.
+// https://github.com/googleapis/librarian/blob/main/doc/language-onboarding.md#generate
+type GenerateFlags struct {
+	Librarian string
+	Input     string
+	Output    string
+	Source    string
+}
+
+// ConfigureFlags holds flags for the `configure` command.
+// https://github.com/googleapis/librarian/blob/main/doc/language-onboarding.md#configure
+type ConfigureFlags struct {
+	Librarian string
+	Input     string
+	Repo      string
+	Source    string
+	Output    string
+}
+
+// ReleaseInitFlags holds flags for the `release-init` command.
+// https://github.com/googleapis/librarian/blob/main/doc/language-onboarding.md#release-init
+type ReleaseInitFlags struct {
+	Librarian string
+	Repo      string
+	Output    string
+}
+
+// LanguageContainerFunctions lists the functions a language container
+// defines to accept requests from Librarian CLI.
+type LanguageContainerFunctions struct {
+	Generate    func(ctx context.Context, flags *GenerateFlags)
+	Configure   func(ctx context.Context, flags *ConfigureFlags)
+	ReleaseInit func(ctx context.Context, flags *ReleaseInitFlags)
+}
+
+// Entry point for a language container. This parses the arguments and
+// calls the corresponding function in the functions struct.
+//
+// A language container defines the following main function:
+//
+// ```
+//
+//	func main() {
+//		cmd.LanguageContainerMain(os.Args, cmd.LanguageContainerFunctions{ ... })
+//	}
+//
+// ```
+func LanguageContainerMain(args []string, functions LanguageContainerFunctions) {
+	// TODO: Parse the arguments correctly.
+	if len(args) > 0 && args[0] == "generate" && functions.Generate != nil {
+		generateFlags := GenerateFlags{
+			Librarian: "/librarian",
+			Input:     "/input",
+			Output:    "/output",
+			Source:    "/source",
+		}
+		functions.Generate(context.Background(), &generateFlags)
+	}
+}

languagecontainer/cmd/cmd_test.go

@@ -0,0 +1,50 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//	https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cmd
+
+import (
+	"context"
+	"testing"
+)
+
+func TestLanguageContainerMain_ParseArguments(t *testing.T) {
+	var calledFunction string
+	for _, test := range []struct {
+		name      string
+		arguments []string
+		functions LanguageContainerFunctions
+	}{
+		{
+			name: "parse generate command",
+			arguments: []string{
+				"generate",
+			},
+			functions: LanguageContainerFunctions{
+				Generate: func(ctx context.Context, flags *GenerateFlags) {
+					calledFunction = "generate"
+				},
+			},
+		},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			calledFunction = "None"
+			LanguageContainerMain(test.arguments, test.functions)
+			if calledFunction != test.arguments[0] {
+				t.Errorf("LanguageContainerMain didn't call the correct function. Expected %s, got %s",
+					test.arguments[0], calledFunction)
+			}
+		})
+	}
+}

languagecontainer/execv/execv.go

@@ -0,0 +1,51 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package execv
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"log/slog"
+	"os"
+	"os/exec"
+	"strings"
+)
+
+// Run executes a command in a specified working directory and logs its output.
+func Run(ctx context.Context, args []string, workingDir string) error {
+	cmd := exec.CommandContext(ctx, args[0], args[1:]...)
+	cmd.Env = os.Environ()
+	cmd.Dir = workingDir
+	slog.Debug("librariangen: running command", "command", strings.Join(cmd.Args, " "), "dir", cmd.Dir)
+
+	output, err := cmd.Output()
+	if len(output) > 0 {
+		slog.Debug("librariangen: command stdout", "output", string(output))
+	}
+	if err != nil {
+		var exitErr *exec.ExitError
+		if errors.As(err, &exitErr) {
+			// The command ran and exited with a non-zero exit code.
+			if len(exitErr.Stderr) > 0 {
+				slog.Debug("librariangen: command stderr", "output", string(exitErr.Stderr))
+			}
+			return fmt.Errorf("librariangen: command failed with exit error: %s: %w", exitErr.Stderr, err)
+		}
+		// Another error occurred (e.g., command not found).
+		return fmt.Errorf("librariangen: command failed: %w", err)
+	}
+	return nil
+}

languagecontainer/execv/execv_test.go

@@ -0,0 +1,79 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package execv
+
+import (
+	"context"
+	"errors"
+	"os/exec"
+	"strings"
+	"testing"
+)
+
+func TestRun(t *testing.T) {
+	tests := []struct {
+		name         string
+		args         []string
+		wantErr      bool
+		wantExit     int
+		wantInStderr string
+	}{
+		{
+			name:    "valid command",
+			args:    []string{"echo", "hello"},
+			wantErr: false,
+		},
+		{
+			name:    "invalid command",
+			args:    []string{"command-that-does-not-exist"},
+			wantErr: true,
+		},
+		{
+			name:     "command with non-zero exit",
+			args:     []string{"sh", "-c", "exit 1"},
+			wantErr:  true,
+			wantExit: 1,
+		},
+		{
+			name:         "command with stderr output",
+			args:         []string{"sh", "-c", "echo 'test error' >&2; exit 1"},
+			wantErr:      true,
+			wantExit:     1,
+			wantInStderr: "test error",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := Run(context.Background(), tt.args, ".")
+			if (err != nil) != tt.wantErr {
+				t.Fatalf("Run() error = %v, wantErr %v", err, tt.wantErr)
+			}
+
+			if !tt.wantErr {
+				return
+			}
+
+			var exitErr *exec.ExitError
+			if errors.As(err, &exitErr) {
+				if tt.wantExit != 0 && exitErr.ExitCode() != tt.wantExit {
+					t.Errorf("Run() exit code = %d, want %d", exitErr.ExitCode(), tt.wantExit)
+				}
+				if tt.wantInStderr != "" && !strings.Contains(string(exitErr.Stderr), tt.wantInStderr) {
+					t.Errorf("Run() stderr = %q, want contains %q", string(exitErr.Stderr), tt.wantInStderr)
+				}
+			}
+		})
+	}
+}

languagecontainer/go.mod

@@ -0,0 +1,33 @@
+// Module languagecontainer provides packages to be shared
+// with language container implementations.
+module github.com/googleapis/librarian/languagecontainer
+
+go 1.25.0
+
+require github.com/googleapis/librarian v0.0.0
+
+replace github.com/googleapis/librarian => ../
+
+require (
+	dario.cat/mergo v1.0.2 // indirect
+	github.com/Microsoft/go-winio v0.6.2 // indirect
+	github.com/ProtonMail/go-crypto v1.3.0 // indirect
+	github.com/cloudflare/circl v1.6.1 // indirect
+	github.com/cyphar/filepath-securejoin v0.4.1 // indirect
+	github.com/emirpasic/gods v1.18.1 // indirect
+	github.com/go-git/gcfg v1.5.1-0.20230307220236-3a3c6141e376 // indirect
+	github.com/go-git/go-billy/v5 v5.6.2 // indirect
+	github.com/go-git/go-git/v5 v5.16.2 // indirect
+	github.com/golang/groupcache v0.0.0-20241129210726-2c02b8208cf8 // indirect
+	github.com/jbenet/go-context v0.0.0-20150711004518-d14ea06fba99 // indirect
+	github.com/kevinburke/ssh_config v1.4.0 // indirect
+	github.com/klauspost/cpuid/v2 v2.3.0 // indirect
+	github.com/pjbgf/sha1cd v0.5.0 // indirect
+	github.com/sergi/go-diff v1.4.0 // indirect
+	github.com/skeema/knownhosts v1.3.1 // indirect
+	github.com/xanzy/ssh-agent v0.3.3 // indirect
+	golang.org/x/crypto v0.42.0 // indirect
+	golang.org/x/net v0.44.0 // indirect
+	golang.org/x/sys v0.36.0 // indirect
+	gopkg.in/warnings.v0 v0.1.2 // indirect
+)