rpmmd: pass in cache directory explicitly

rpmmd looked at the CACHE_DIRECTORY environment variable to set a path
for the dnf repository cache.  Aside from being a smelly thing to do
from a library, this breaks osbuild-pipeline and osbuild-dnf-json-tests,
which don't run as systemd services and thus don't have CACHE_DIRECTORY
set.

Explicitly pass the cache directory to rpmmd. Keep using a path based on
CACHE_DIRECTORY for osbuild-composer. Use the user's `.cache` directory
for osbuild-pipeline and a temporary directory for the tests.

cmd/osbuild-composer/main.go

@@ -7,6 +7,7 @@ import (
 	"github.com/osbuild/osbuild-composer/internal/rcm"
 	"io/ioutil"
 	"log"
+	"path"
 	"os"
 
 	"github.com/osbuild/osbuild-composer/internal/common"
@@ -73,7 +74,12 @@ func main() {
 	weldrListener := composerListeners[0]
 	jobListener := composerListeners[1]
 
-	rpm := rpmmd.NewRPMMD()
+	cacheDirectory, ok := os.LookupEnv("CACHE_DIRECTORY")
+	if !ok {
+		log.Fatal("CACHE_DIRECTORY is not set. Is the service file missing CacheDirectory=?")
+	}
+
+	rpm := rpmmd.NewRPMMD(path.Join(cacheDirectory, "rpmmd"))
 	distros := distro.NewRegistry([]string{"/etc/osbuild-composer", "/usr/share/osbuild-composer"})
 
 	distribution, err := distros.FromHost()

cmd/osbuild-dnf-json-tests/main.go

@@ -57,7 +57,7 @@ func TestFetchChecksum(quiet bool, dir string) {
 	if !quiet {
 		log.Println("Running TestFetchChecksum on:", dir)
 	}
-	rpmMetadata := rpmmd.NewRPMMD()
+	rpmMetadata := rpmmd.NewRPMMD(path.Join(dir, "rpmmd"))
 	_, c, err := rpmMetadata.FetchMetadata([]rpmmd.RepoConfig{repoCfg}, "platform:f31")
 	if err != nil {
 		log.Panic("Failed to fetch checksum:", err)

cmd/osbuild-pipeline/main.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"path"
 
 	"github.com/osbuild/osbuild-composer/internal/common"
 
@@ -87,7 +88,12 @@ func main() {
 	}
 	packages = append(pkgs, packages...)
 
-	rpmmd := rpmmd.NewRPMMD()
+	home, err := os.UserHomeDir()
+	if err != nil {
+		panic("os.UserHomeDir(): " + err.Error())
+	}
+
+	rpmmd := rpmmd.NewRPMMD(path.Join(home, ".cache/osbuild-composer/rpmmd"))
 	packageSpecs, checksums, err := rpmmd.Depsolve(packages, exclude_pkgs, d.Repositories(archArg), d.ModulePlatformID(), false)
 	if err != nil {
 		panic("Could not depsolve: " + err.Error())

internal/rpmmd/repository.go

@@ -6,7 +6,6 @@ import (
 	"io/ioutil"
 	"os"
 	"os/exec"
-	"path"
 	"sort"
 	"time"
 
@@ -211,22 +210,22 @@ func runDNF(command string, arguments interface{}, result interface{}) error {
 	return nil
 }
 
-type rpmmdImpl struct{}
-
-func NewRPMMD() RPMMD {
-	return &rpmmdImpl{}
+type rpmmdImpl struct {
+	CacheDir string
 }
 
-func (*rpmmdImpl) FetchMetadata(repos []RepoConfig, modulePlatformID string) (PackageList, map[string]string, error) {
-	cacheDirectory, ok := os.LookupEnv("CACHE_DIRECTORY")
-	if !ok {
-		panic("CACHE_DIRECTORY is not set. Is the service file missing CacheDirectory=?")
+func NewRPMMD(cacheDir string) RPMMD {
+	return &rpmmdImpl{
+		CacheDir: cacheDir,
 	}
+}
+
+func (r *rpmmdImpl) FetchMetadata(repos []RepoConfig, modulePlatformID string) (PackageList, map[string]string, error) {
 	var arguments = struct {
 		Repos            []RepoConfig `json:"repos"`
 		CacheDir         string       `json:"cachedir"`
 		ModulePlatformID string       `json:"module_platform_id"`
-	}{repos, path.Join(cacheDirectory, "rpmmd"), modulePlatformID}
+	}{repos, r.CacheDir, modulePlatformID}
 	var reply struct {
 		Checksums map[string]string `json:"checksums"`
 		Packages  PackageList       `json:"packages"`
@@ -238,11 +237,7 @@ func (*rpmmdImpl) FetchMetadata(repos []RepoConfig, modulePlatformID string) (Pa
 	return reply.Packages, reply.Checksums, err
 }
 
-func (*rpmmdImpl) Depsolve(specs, excludeSpecs []string, repos []RepoConfig, modulePlatformID string, clean bool) ([]PackageSpec, map[string]string, error) {
-	cacheDirectory, ok := os.LookupEnv("CACHE_DIRECTORY")
-	if !ok {
-		panic("CACHE_DIRECTORY is not set. Is the service file missing CacheDirectory=?")
-	}
+func (r *rpmmdImpl) Depsolve(specs, excludeSpecs []string, repos []RepoConfig, modulePlatformID string, clean bool) ([]PackageSpec, map[string]string, error) {
 	var arguments = struct {
 		PackageSpecs     []string     `json:"package-specs"`
 		ExcludSpecs      []string     `json:"exclude-specs"`
@@ -250,7 +245,7 @@ func (*rpmmdImpl) Depsolve(specs, excludeSpecs []string, repos []RepoConfig, mod
 		CacheDir         string       `json:"cachedir"`
 		ModulePlatformID string       `json:"module_platform_id"`
 		Clean            bool         `json:"clean,omitempty"`
-	}{specs, excludeSpecs, repos, path.Join(cacheDirectory, "rpmmd"), modulePlatformID, clean}
+	}{specs, excludeSpecs, repos, r.CacheDir, modulePlatformID, clean}
 	var reply struct {
 		Checksums    map[string]string `json:"checksums"`
 		Dependencies []PackageSpec     `json:"dependencies"`