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XCA is an x509 certificate generation tool, handling RSA, DSA and EC keys, certificate signing requests (PKCS#10) and CRLs. It supports a broad range of import and export formats.

I had long been aware of the [effort of cznic](https://gitlab.com/cznic/sqlite) to automatically translate the C source of SQLite to Go while avoiding the complexity CGo would introduce. SQLite was always meant to be a database you embed into your application, and I was curious what tradeoffs that meant, if any, and just generally how it differed from the usual suspects (PostgreSQL, etc.). To explore these trade-offs and differences, I decided to dive deeper into the usage of this library. SQLite is a single-writer multiple-reader database. Using just a single instance of database/sql.DB will not work well with this, because it will make it hard to avoid receiving SQLITE_BUSY errors when multiple writers try to run at the same time (because sql.DB is a connection pool). So we will need to separate readers from writers by making two instances of database/sql.DB and limiting the writer to a single [MaxOpenConn](https://pkg.go.dev/database/sql#DB.SetMaxOpenConns) and the reader to as many as you require. So far, SQLite is behaving remarkably like other databases apart from the single-writer gotcha; we still have connections and per-connection settings. The usual way to pass these settings is usually in the DSN you pass to [sql.Open](https://pkg.go.dev/database/sql#Open) and this is [definitely possible](https://pkg.go.dev/modernc.org/sqlite#Driver.Open), but I find that it would be more straightforward if I could just run my custom SQL when a new connection is made[1]. We can do that with [sqlite.RegisterConnectionHook](https://pkg.go.dev/modernc.org/sqlite#RegisterConnectionHook). Now the question is what settings to use, because [there are quite a few of them](https://www.sqlite.org/pragma.html). These are the ones I am using personally: - `PRAGMA journal_mode = WAL;` Use write-ahead-logging. Better concurrency, but with an edge-case: with heavy writers, the wal can grow idefinitely ([see for more](https://www.sqlite.org/cgi/src/doc/wal2/doc/wal2.md)). I don't expect this will happen in my use-case. For a good description on the various jornal modes, [see this blogpost](https://www.mycelial.com/learn/sqlite-journal-mode-options). - `PRAGMA synchronous = NORMAL;` Since with the WAL journal mode, this is safe, there is no reason to use FULL. - `PRAGMA temp_store = MEMORY;` Let's store temporary indices, tables, etc. in memory, my use-case is not very resource-constrained to require using the filesystem (also, [this is a fun read](https://www.sqlite.org/fasterthanfs.html) if we are talking about additional syscalls to the kernel) - `PRAGMA mmap_size = 30000000000; -- 30GB` Just making sure, access to my database is always done with memory-mapped I/O. - `PRAGMA busy_timeout = 5000;` How much time to wait in milliseconds after which SQLITE_BUSY is returned when waiting for the db to unlock. - `PRAGMA automatic_index = true;` Make sure [automatic indexing](https://www.sqlite.org/optoverview.html#autoindex) is enabled, it can only help, and is a great way to get warnings about indexes that should be created. - `PRAGMA foreign_keys = ON;` Make sure foreign key enforcement is enabled. - `PRAGMA analysis_limit = 1000;` Make sure [ANALYZE](https://www.sqlite.org/lang_analyze.html#approx) returns quickly in case the DB gets large. - `PRAGMA trusted_schema = OFF;` No idea what security audited functions are, but this setting makes sure only those can be run. The manual page tells me to turn it off anyway, so let's do that. Not all of these settings are per-connection settings, but it doesn't hurt to always run all of these on every connection, and having a single "Init SQL" makes things simpler. Let's deal with explicit transactions next. The default transaction mode is DEFERRED, meaning that it depends on the next statement what type of transaction is started (if a SELECT statement comes first, a read transaction is started, with the possibility of upgrading it to a write transaction depending on the statements that follow). With our setup, there should never be multiple writers concurrently, so making all transactions write transactions from the get-go (with BEGIN IMMEDIATE) can only help us show if this invariant is violated. Putting this all together, this is the code we arrive at: ```go package main import ( "bytes" "context" "crypto/sha1" "database/sql" "database/sql/driver" "encoding/hex" "fmt" "time" "modernc.org/sqlite" ) type DB struct { dbPath string Read *sql.DB Write *sql.DB } const initSQL = ` PRAGMA journal_mode = WAL; PRAGMA synchronous = NORMAL; PRAGMA temp_store = MEMORY; PRAGMA mmap_size = 30000000000; -- 30GB PRAGMA busy_timeout = 5000; PRAGMA automatic_index = true; PRAGMA foreign_keys = ON; PRAGMA analysis_limit = 1000; PRAGMA trusted_schema = OFF; ` func New(ctx context.Context, dbPath string) (db *DB, err error) { db = &DB{ dbPath: dbPath, } // make sure every opened connection has the settings we expect sqlite.RegisterConnectionHook(func(conn sqlite.ExecQuerierContext, _ string) error { _, err = conn.ExecContext(ctx, initSQL, nil) return err }) write, err := sql.Open("sqlite", "file:"+db.dbPath) if err != nil { return } // only a single writer ever, no concurrency write.SetMaxOpenConns(1) write.SetConnMaxIdleTime(time.Minute) if err != nil { return } read, err := sql.Open("sqlite", "file:"+db.dbPath) if err != nil { return } // readers can be concurrent read.SetMaxOpenConns(100) read.SetConnMaxIdleTime(time.Minute) db.Read = read db.Write = write return } func (db *DB) InTransaction(ctx context.Context, tx func(context.Context, *sql.Conn) error) (err error) { // cancel anything that takes longer than 5 seconds var cancel func() ctx, cancel = context.WithTimeout(ctx, time.Duration(5*time.Second)) defer cancel() // separate conn thats just for us // so that the transactions queries are executed together conn, err := db.Write.Conn(ctx) if err != nil { return } defer conn.Close() _, err = conn.ExecContext(ctx, "BEGIN IMMEDIATE TRANSACTION") if err != nil { return } defer func() { if r := recover(); r != nil || err != nil { if _, err = conn.ExecContext(ctx, "ROLLBACK"); err != nil { return } } }() err = tx(ctx, conn) if err != nil { return } _, err = conn.ExecContext(ctx, "COMMIT") return } ``` Just as a small added bonus, it's also very easy to register our own go functions that we can then call from SQL. In this example, we define the sha1 function, receiving and returning a single argument, and always returning the same output for the same input (thus the deterministic). For more information, [see the docs](https://www.sqlite.org/appfunc.html) ```go func registerFuncs() { // lets add our own sha1 hash function usable from SQL sqlite.MustRegisterDeterministicScalarFunction( "sha1", 1, func(ctx *sqlite.FunctionContext, args []driver.Value) (driver.Value, error) { var arg *bytes.Buffer switch argTyped := args[0].(type) { case string: arg = bytes.NewBuffer([]byte(argTyped)) case []byte: arg = bytes.NewBuffer(argTyped) default: return nil, fmt.Errorf("expected argument to be a string, got: %T", argTyped) } h := sha1.Sum(arg.Bytes()) return hex.EncodeToString(h), nil }, ) } ``` In conclusion, this solution works perfectly well for most of the usage scenarios out there where immense scaling is neither expected nor needed. There are faster ways to use SQLite with Go (see the [excellent cvilsmeier benchmarks](https://github.com/cvilsmeier/go-sqlite-bench)), but its still plenty-fast enough, and avoiding CGo makes it very convenient also. [1]: This is another thing that database/sql.DB being a connection pool makes harder.

One of the most satisfying aspects of running free and open source software is the ability to be able to continually tinker with your setup, limited …

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nginx config snippets: gzip, catchall, domain c14n, ssl, uwsgi, php, wordpress - nginx-config-snippets/ubuntu/etc/init/mounted-run-extra.conf at master · danielrichman/nginx-config-snippets

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Here is an example of routing calls over time in Asterisk. Assume that the /etc/asterisk/extensions.conf file has a configured context for the trunk with the following parameters: And to resolve the time calls to different phones, we will point out for the context of this trunk only nested contexts: In fact, daytime, nighttime, sunday are … Continue reading "Asterisk time based routing"

CakePHP Potion - Painless Gulp for CakePHP. Contribute to alanrodas/potion development by creating an account on GitHub.

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Penetration Testing tools written in python! Contribute to bluedangerforyou/python-sec-tools development by creating an account on GitHub.

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This article describes the ideas behind the system I designed and built myself. It started out as a "I wonder what it would sound like if..." exercise, and turned into the system I would choose to listen to even if I had the chance to swap it for commercial gear. It includes the first speakers I ever…

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After using Google Blogger for nearly 9 years to host myblog, I decided to migrate to aGit-based blog. My blog is now primarily hosted onGitHub using GitHubP...

Applicant Tracking System (maintained code base). Contribute to opencats/OpenCATS development by creating an account on GitHub.

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GET INVOLVED Thanks for your interest in helping Library Freedom Project! An organization of our size (tiny!) is not very well equipped to handle a…

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DNS-Blocklists: For a better internet - keep the internet clean! - hagezi/dns-blocklists

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This Design World website educates engineers designing moving machinery with linear axes and actuators for automation in industrial and end-user builds. It details specification and integration of linear guides and slides, drives (such as screws and motors), linear feedback, linear actuators, stages, and gantries.

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The portal for geek projects of Jason A. Donenfeld, also known as ZX2C4.

CC Address Plugin for Redmine... Contribute to peelman/redmine_cc_addresses development by creating an account on GitHub.

Resolves an issue where RemoteApp sessions are disconnected when all RemoteApp windows and user-launched notification area icons are closed.

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