private String getManifestDigest()

in plugins/docker/base-image/src/main/java/co/elastic/gradle/dockerbase/DockerLockfileTask.java [329:369]
39 lines of code
6 McCabe index (conditional complexity)

    private String getManifestDigest(String image) {
        if (manifestDigest != null) {
            return manifestDigest;
        }
        DockerUtils daemonActions = new DockerUtils(getExecOperations());
        return RetryUtils.retry(() -> {
                    try (ByteArrayOutputStream stdout = new ByteArrayOutputStream()) {
                        daemonActions.exec(spec -> {
                            spec.setStandardOutput(stdout);
                            spec.commandLine("docker", "manifest", "inspect", image);
                        });
                        try (InputStreamReader reader = new InputStreamReader(new ByteArrayInputStream(stdout.toByteArray()))) {
                            ObjectMapper mapper = new ObjectMapper();
                            JsonNode root = mapper.readTree(reader);
                            String digest = null;
                            Iterator<JsonNode> manifests = root.path("manifests").elements();
                            while (manifests.hasNext()) {
                                JsonNode manifest = manifests.next();
                                if (getArchitecture().get().dockerName().equals(manifest.path("platform").path("architecture").asText())) {
                                    digest = manifest.path("digest").asText(null);
                                    break;
                                }
                            }
                            if (digest == null) {
                                // Happens when the tag does not point to a manifest list
                                // We could make this work for a single platform if we really wanted to, for now it's an error
                                throw new GradleException("Can't find manifest digest from docker output. " +
                                                          "Does the image have a manifest?\n" + stdout
                                );
                            }
                            manifestDigest = digest;
                            return digest;
                        }
                    } catch (IOException e) {
                        throw new UncheckedIOException("Failed to read the image manifest", e);
                    }
                })
                .maxAttempt(3)
                .exponentialBackoff(1000, 100000)
                .execute();
    }