Sadie  Ratke

Sadie Ratke

1596350880

Compilation time that mixing Objective-C with Swift

My previous article describes how to use a DI pattern to reduce compilation time and make your code loosely coupled on a pure Swift project. Today, let’s dig into how the build system determines which files should be recompiled and find out the best way to reduce the compilation time when mixing Objective-C and Swift, your experiences are different from mine, but some useful tricks may be useful for you. If I have made something wrong, please fix me.

Summary

1\. The Context Of Swift Compiler
  1.1\. Swift Driver, Frontend jobs
  1.2\. Demo profiling of dependency analysis

2\. Compilation time
  2.1\. The bad cases of compilation time
  2.2\. The ways to fix compilation time issue

The Context of Swift Compiler

I only pick the related context of the Swift compiler as the basic required knowledge before you read this article.

Swift Driver, Frontend jobs

Swift’s compiler driver is a program that coordinates the compilation of Swift source code into various compiled results: executables, libraries, object files, Swift modules, and interfaces, etc. The driver is the program that’s run when you invoke swift or swiftc. This doesn’t actually compile anything itself; instead, it invokes other tools to produce the desired output. e.g. The frontend.

The frontend is the program that actually compiles code (and in interpreter mode, executes it via a JIT).The Xcode build system does lots of work after you tapping command+B, you can check it out on your Xcode report navigator(Command + 9). The first command is **swift -frontend**

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A normal Swift compilation starts off with as many frontend jobs as input files. Each invocation of the Swift frontend parses every file in the module but also has a particular file marked as the primary file. A job is only responsible for compiling its primary file, and only does as much work as it needs to compile that file, lazily type-checking declarations in other files in the module. For example, the following pic depicts the fronted jobs consist of Compiling Feature3.swift and PrivateModel.swift.

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These two files also treat as primary files. (swift -frontend -c -primary-file Feature3.swift) A frontend job emits diagnostics, an object file, dependency information, and a _partial module file. _The build system is responsible for generating these files specified by the Feature3-OutputFileMap.json file placing at /Users/vedon/Library/Developer/Xcode/DerivedData/DI-bgjyihycmgnhgmehdddbteazwwqm/Build/Intermediates.noindex/Pods.build/Debug-iphonesimulator/Feature3.build/Objects-normal/x86_64 folder.

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The special "" entry is used for outputs that apply to the entire build. The pic below shows the content of Feature3-master.swiftdeps.

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#swift #objective-c

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Compilation time that mixing Objective-C with Swift
Arvel  Parker

Arvel Parker

1591611780

How to Find Ulimit For user on Linux

How can I find the correct ulimit values for a user account or process on Linux systems?

For proper operation, we must ensure that the correct ulimit values set after installing various software. The Linux system provides means of restricting the number of resources that can be used. Limits set for each Linux user account. However, system limits are applied separately to each process that is running for that user too. For example, if certain thresholds are too low, the system might not be able to server web pages using Nginx/Apache or PHP/Python app. System resource limits viewed or set with the NA command. Let us see how to use the ulimit that provides control over the resources available to the shell and processes.

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MEAN Stack Tutorial MongoDB ExpressJS AngularJS NodeJS

We are going to build a full stack Todo App using the MEAN (MongoDB, ExpressJS, AngularJS and NodeJS). This is the last part of three-post series tutorial.

MEAN Stack tutorial series:

AngularJS tutorial for beginners (Part I)
Creating RESTful APIs with NodeJS and MongoDB Tutorial (Part II)
MEAN Stack Tutorial: MongoDB, ExpressJS, AngularJS and NodeJS (Part III) 👈 you are here
Before completing the app, let’s cover some background about the this stack. If you rather jump to the hands-on part click here to get started.

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Tyrique  Littel

Tyrique Littel

1597723200

FreeBSD s3cmd failed [SSL CERTIFICATE_VERIFY_FAILED]

When I install s3cmd package on my FreeBSD system and try to use the s3cmd command I get the following error:

_ERROR: Test failed: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (ssl.c:1091)

How do I fix this problem on FreeBSD Unix system?

Amazon Simple Storage Service (s3 ) is object storage through a web service interface or API. You can store all sorts of files. FreeBSD is free and open-source operating systems. s3cmd is a command-line utility for the Unix-like system to upload, download files to AWS S3 service from the command line.

ERROR: Test failed: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed error and solution

This error indicates that you don’t have packages correctly installed, especially SSL certificates. Let us see how to fix this problem and install s3cmd correctly on FreeBSD to get rid of the problem.

How to install s3cmd on FreeBSD

Search for s3cmd package:

$ pkg search s3cmd

Execute the following command and make sure you install Python 3.x package as Python 2 will be removed after 2020:

$ sudo pkg install py37-s3cmd-2.1.0

Updating FreeBSD repository catalogue...
FreeBSD repository is up to date.
All repositories are up to date.
Checking integrity... done (0 conflicting)
The following 8 package(s) will be affected (of 0 checked):

New packages to be INSTALLED:
	libffi: 3.2.1_3
	py37-dateutil: 2.8.1
	py37-magic: 5.38
	py37-s3cmd: 2.1.0
	py37-setuptools: 44.0.0
	py37-six: 1.14.0
	python37: 3.7.8
	readline: 8.0.4

Number of packages to be installed: 8

The process will require 118 MiB more space.

Proceed with this action? [y/N]: y
[rsnapshot] [1/8] Installing readline-8.0.4...
[rsnapshot] [1/8] Extracting readline-8.0.4: 100%
[rsnapshot] [2/8] Installing libffi-3.2.1_3...
....
..
[rsnapshot] [8/8] Extracting py37-s3cmd-2.1.0: 100%
=====
Message from python37-3.7.8:

--
Note that some standard Python modules are provided as separate ports
as they require additional dependencies. They are available as:

py37-gdbm       databases/py-gdbm@py37
py37-sqlite3    databases/py-sqlite3@py37
py37-tkinter    x11-toolkits/py-tkinter@py37

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Yoshiko  Jones

Yoshiko Jones

1598195340

How to configure AWS SES with Postfix MTA

How do I configure Amazon SES With Postfix mail server to send email under a CentOS/RHEL/Fedora/Ubuntu/Debian Linux server?

Amazon Simple Email Service (SES) is a hosted email service for you to send and receive email using your email addresses and domains. Typically SES used for sending bulk email or routing emails without hosting MTA. We can use Perl/Python/PHP APIs to send an email via SES. Another option is to configure Linux or Unix box running Postfix to route all outgoing emails via SES.

  • » Remove sendmail
  • » Install postfix
  • » Configuring postfix for SES
  • » Test postfix

Procedure to configure AWS SES with Postfix

Before getting started with Amazon SES and Postfix, you need to sign up for AWS, including SES. You need to verify your email address and other settings. Make sure you create a user for SES access and download credentials too.

Step 1 – Uninstall Sendmail if installed

If sendmail installed remove it. Debian/Ubuntu Linux user type the following apt command/apt-get command:

$`` sudo apt --purge remove sendmail

CentOS/RHEL user type the following yum command or dnf command on Fedora/CentOS/RHEL 8.x:

$`` sudo yum remove sendmail

$`` sudo dnf remove sendmail

Sample outputs from CentOS 8 server:

Dependencies resolved.
===============================================================================
 Package           Architecture  Version               Repository         Size
===============================================================================
Removing:
 sendmail          x86_64        8.15.2-32.el8         @AppStream        2.4 M
Removing unused dependencies:
 cyrus-sasl        x86_64        2.1.27-1.el8          @BaseOS           160 k
 procmail          x86_64        3.22-47.el8           @AppStream        369 k

Transaction Summary
===============================================================================
Remove  3 Packages

Freed space: 2.9 M
Is this ok [y/N]: y

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Creating RESTful APIs with NodeJS and MongoDB Tutorial

Welcome to this tutorial about RESTful API using Node.js (Express.js) and MongoDB (mongoose)! We are going to learn how to install and use each component individually and then proceed to create a RESTful API.

MEAN Stack tutorial series:

AngularJS tutorial for beginners (Part I)
Creating RESTful APIs with NodeJS and MongoDB Tutorial (Part II) 👈 you are here
MEAN Stack Tutorial: MongoDB, ExpressJS, AngularJS and NodeJS (Part III)

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