Serverless DeepDive #10：一時ファイルの置き場所を比較してみる

const { randomUUID } = require("node:crypto");
const { readFileSync, writeFileSync } = require("node:fs");
const { S3Client, PutObjectCommand, GetObjectCommand } = require("@aws-sdk/client-s3");
const sdkVersion = require("@aws-sdk/client-s3/package.json").version;
const initId = randomUUID();
const s3 = new S3Client({ maxAttempts: 1 });
const packagePath = "/var/task/lab-result.json";
const tmpPath = "/tmp/lab-result.json";
let count = 0;
function read(path) {
try {
return { found: true, value: JSON.parse(readFileSync(path, "utf8")) };
} catch (error) {
if (error.code !== "ENOENT") throw error;
return { found: false };
}
}
exports.handler = async (event, context) => {
if (!event || typeof event !== "object" || Array.isArray(event))
throw new TypeError("event must be an object");
const action = event.action ?? "read";
if (!["read", "write"].includes(action)) throw new TypeError("unknown action");
for (const field of ["run_id", "id", "key_id"]) {
if (typeof event[field] !== "string" || !/^[a-z0-9-]{1,64}$/.test(event[field]))
throw new TypeError(`${field} must match [a-z0-9-]{1,64}`);
}
if (action === "write" && (typeof event.value !== "string" || event.value.length > 128))
throw new TypeError("value must be a string of at most 128 characters");
const bucket = process.env.LAB_EVIDENCE_BUCKET;
const prefix = process.env.LAB_EVIDENCE_PREFIX;
if (!bucket || !prefix) throw new Error("storage is not configured");
const key = `${prefix + event.run_id}/${event.key_id}.json`;
const record = {
phase: "file-result",
id: event.id,
run_id: event.run_id,
action,
request_id: context.awsRequestId,
init_id: initId,
count: ++count,
function_id: process.env.LAB_FUNCTION_ID,
config: process.env.CONFIG_MARK,
node: process.version,
sdk: sdkVersion,
version: context.functionVersion,
package_before: read(packagePath),
tmp_before: read(tmpPath),
};
if (action === "write") {
const value = { value: event.value, saved_by: initId, request_id: context.awsRequestId };
try {
writeFileSync(packagePath, JSON.stringify(value));
record.package_write = { succeeded: true };
} catch (error) {
record.package_write = { succeeded: false, code: error.code };
}
writeFileSync(tmpPath, JSON.stringify(value));
record.tmp_write = { succeeded: true };
const saved = await s3.send(
new PutObjectCommand({ Bucket: bucket, Key: key, Body: JSON.stringify(value) }),
);
record.s3_write = { succeeded: true, http_status: saved.$metadata.httpStatusCode };
}
record.package_after = read(packagePath);
record.tmp_after = read(tmpPath);
try {
const loaded = await s3.send(new GetObjectCommand({ Bucket: bucket, Key: key }));
record.s3_read = {
found: true,
value: JSON.parse(await loaded.Body.transformToString()),
http_status: loaded.$metadata.httpStatusCode,
};
} catch (error) {
if (error.name !== "NoSuchKey") throw error;
record.s3_read = {
found: false,
code: error.name,
http_status: error.$metadata?.httpStatusCode,
};
}
console.log(JSON.stringify(record));
return record;
};

AWS_PROFILE=YOUR_PROFILE aws lambda get-function-configuration \
--region ap-northeast-1 --function-name YOUR_PRIMARY_NAME \
--query '{RevisionId:RevisionId,Environment:Environment}'

AWS_PROFILE=YOUR_PROFILE AWS_MAX_ATTEMPTS=1 aws lambda update-function-configuration \
--region ap-northeast-1 --function-name YOUR_PRIMARY_NAME \
--revision-id YOUR_LATEST_REVISION_ID \
--environment file://environment-b.json

AWS_PROFILE=YOUR_PROFILE aws lambda wait function-updated-v2 \
--region ap-northeast-1 --function-name YOUR_PRIMARY_NAME