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Simple connect a mongo client container to a mongodb container

I tried this on OSX. It probably works on Windows too.

In this article we create a container with mongodb and some contents and then connect to it from another container.
Just for personal reasons the client container is really a “aspnet container” and not connected to mongodb to start with.

Even though I liked typing my way around Docker I tried and discovered the free Kitematic by Docker.
It gives me a very simple overview but I hope it to evolve some in the future to include a little more, like the git-githubdesktop-sourcetree journey.

Create a mongo database with contents

Open Kitematic and create a mongodb container.

Select Exec to get a terminal.

Now, inside the container, connect to the built-in mongo:

mongo

Just for fun, see what databases we have:

show dbs

Create two new records.

db.runCommand({insert:"projects", documents:[{_id:1, name:"Alpha"}] })
db.runCommand({insert:"projects", documents:[{_id:2, name:"Beta"}] })

The result should be

{ "n" : 1, "ok" : 1 }

for each call where “n” denotes the number of records inserted and “ok” the success.

See what we have  of databases again, to find the new database “projects”.

show dbs

Step into the database: (Is this really necessary?)

use projects

Query what we have:

db.runCommand({find:"projects"})

Now we have a container running mongodb with data in it.
You can leave mongodb and the container but make sure it is not stopped.

Create another container

Containerising is about selecting an image and then adapting it to you needs.
I use a lot of dotnet and hence choose to select a dotnet core image.

Search in Kitematic for “aspnetcore” and select one. Which to chose can be complex; by the time of writing there are 2 from Microsoft. Which to choose is another subject and also subject to change.

When the container is started update it and then install mongodb.

apt-get update

apt-get install mongodb

Note: Updating the container with apt-get is something one probably don’t do as such tasks should be scripted. But here we are experimenting.

We don’t want the database in this container, only the client, but is easier to find an apt-get for the whole database than for just a client.

We now have 2 running containers and if you didn’t fiddle around too much they are sharing network.
The network can be inspected:

docker network inspect bridge

which results in something like:

        "Containers": {
             "2fae...eb2a": {
                 "Name": "aspnetcore",
                 ...
                 "IPv4Address": "172.17.0.3/16",
                 ...
 },
             "f565...3856": {
                 "Name": "mongo",
                 ...
                 "IPv4Address": "172.17.0.2/16",
                 ...
 }

There we have the IP addresses. Out of the box Docker containers don’t have a name resolution so we’ll use the IP address to connect.

So connect with:

mongo 172.17.0.2

and query as before:

db.runCommand({find:"projects"})

Yay!
Two connected containers, one running a mongo database and one connected to it and prepared for aspnetcore love.

Aspnet core 1.1 and Visual studio 2017 running in Docker container in OSX

I happen to have OSX as host and Win10 as virtual machine.
I have also mapped a folder so it is reachable from both OSX and Windows.
OSX has Docker installed.

Create the project in Windows/Visual studio 2017

Create a blank solution somewhere both Windows and OSX can reach. In this article I chose

\\mac\home\documents\PROJEKT

Whatever dotnet version is visible at the top of the dialogue is not of interesting as we are creating a solution file and not much more and then we add Dotnet core specific stuff. You can search for the template through “empty” or “blank”.

Add an Aspnet core application project. Keep the standard name of simplicity. The path is in the solution \\Mac\Home\Documents\PROJEKT\Solution1

Dotnet version is still not necessary as it refers to Dotnet framework and we are caring about Dotnet core.

Select Dotnet core 1.1. This text is written in August 2017 and Dotnet core 2 is due November. Select WebApi. Do not add docker support. It would probably not make any change but in this exercise we are targeting running the container in OSX. If you change your mind and do want Docker-for-windows support you can always do that later with the click of a button.

When the project is added compile and run to see that all cog wheels are in place and in working order.

Tip from the trenches: Ctrl-F5 compiles, starts the web server and pop ups a web browser in one click, without having to start the debugger.

Note the URL. It is something like http://localhost:2058/api/values where /api/values is something to briefly remember. See that in the browser window there is the text [“value1″,”value2”]. It is created through the Get method in class Controllers/ValuesController.cs the “normal MVC way”.

Publish in Windows

If you right click the project (=activate the context menu in the solution explorer pane on the WebApplication1 project) there is a choice “Publish…”. AFAIK it is used for Windows or Dotnet framework stuff so leave it be.

Instead we use the CLI for restoring, publishing and activating.

If you open the console in windows you cannot use the UNC path we have put the project in. So instead use pushd like so:

> pushd \\Mac\Home\Documents\PROJEKT\Solution1\WebApplication1

Then restore the files with dotnet restore. Restoring in this case means pulling in all dependencies so we have everything we need.

It will look someting like:

> dotnet restore
Restoring packages for V:\Documents\PROJEKT\Solution1\WebApplication1\WebApplication1.csproj…
Generating MSBuild file V:\Documents\PROJEKT\Solution1\WebApplication1\obj\WebApplication1.csproj.nuget.g.props.
Writing lock file to disk. Path: V:\Documents\PROJEKT\Solution1\WebApplication1\obj\project.assets.json
Restore completed in 1,58 sec for V:\Documents\PROJEKT\Solution1\WebApplication1\WebApplication1.csproj.
Restore completed in 1,81 sec for V:\Documents\PROJEKT\Solution1\WebApplication1\WebApplication1.csproj.
NuGet Config files used:
C:\Users\username\AppData\Roaming\NuGet\NuGet.Config
C:\Program Files (x86)\NuGet\Config\Microsoft.VisualStudio.Offline.config
Feeds used:
https://api.nuget.org/v3/index.json
C:\Program Files (x86)\Microsoft SDKs\NuGetPackages\

Now publish with publish:

> dotnet publish 
Microsoft (R) Build Engine version 15.1.1012.6693
Copyright (C) Microsoft Corporation. All rights reserved.
WebApplication1 -> V:\Documents\PROJEKT\Solution1\WebApplication1\bin\Debug\netcoreapp1.1\WebApplication1.dll

As we didn’t specify an output path we get the result in bin\Debug\netcoreapp1.1\.

> dotnet run
Hosting environment: Production
Content root path: V:\Documents\PROJEKT\Solution1\WebApplication1
Now listening on: http://localhost:5000
Application started. Press Ctrl+C to shut down.

Note the back slashes and that I never said to change OS. We have just started the web server in Windows.

Check it by opening a web browser and go to http://localhost:5000/api/values

You should have [“value1″,”value2”] as output. Nothing surprising.

Shut down the application (ctrl-c in the console) and refresh the browser to verify that we really are surfing to our site and not Visual studio and IIS(express).

If you want to go spelunking in the container try opening a terminal directly or connecting one.

OSX

Open an OSX terminal at your web project, where WebApplication1.csproj is. Typically something like

/Users/username/Documents/PROJEKT/Solution1/WebApplication1

If you do a dotnet run now you get an error.

> dotnet run
/usr/local/share/dotnet/sdk/1.0.1/Sdks/Microsoft.NET.Sdk/build/Microsoft.PackageDependencyResolution.targets(154,5): error : Assets file ‘/Users/username/Documents/PROJEKT/Solution1/WebApplication1/V:/Documents/PROJEKT/Solution1/WebApplication1/obj/project.assets.json’ not found. Run a NuGet package restore to generate this file. [/Users/username/Documents/PROJEKT/Solution1/WebApplication1/WebApplication1.csproj]
/var/folders/5l/1bssc0z152s_shv8j8nb9htm0000gn/T/.NETCoreApp,Version=v1.1.AssemblyAttributes.cs(4,20): error CS0400: The type or namespace name ‘System’ could not be found in the global namespace (are you missing an assembly reference?) [/Users/username/Documents/PROJEKT/Solution1/WebApplication1/WebApplication1.csproj]

Alas restore, publish and run.

> dotnet restore
  Restoring packages for /Users/username/Documents/PROJEKT/Solution1/WebApplication1/WebApplication1.csproj…
  Restore completed in 784.3 ms for /Users/username/Documents/PROJEKT/Solution1/WebApplication1/WebApplication1.csproj.
  Generating MSBuild file /Users/username/Documents/PROJEKT/Solution1/WebApplication1/obj/WebApplication1.csproj.nuget.g.props.
  Writing lock file to disk. Path: /Users/username/Documents/PROJEKT/Solution1/WebApplication1/obj/project.assets.json
  Restore completed in 1.7 sec for /Users/username/Documents/PROJEKT/Solution1/WebApplication1/WebApplication1.csproj.
  NuGet Config files used:
      /Users/username/.nuget/NuGet/NuGet.Config
  Feeds used:
      https://api.nuget.org/v3/index.json

Why we need to restore it again is something I haven’t grokked yet. To be honest – if I hadn’t tricked you into, unnecessarily, restoring on the Windows machine first you wouldn’t have noticed.

> dotnet publish
Microsoft (R) Build Engine version 15.1.548.43366
Copyright (C) Microsoft Corporation. All rights reserved.
  WebApplication1 -> /Users/username/Documents/PROJEKT/Solution1/WebApplication1/bin/Debug/netcoreapp1.1/WebApplication1.dll

> dotnet run
Hosting environment: Production
Content root path: /Users/username/Documents/PROJEKT/Solution1/WebApplication1
Now listening on: http://localhost:5000
Application started. Press Ctrl+C to shut down.

Open another console and curl:

> curl localhost:5000/api/values

to get the result:

[“value1″,”value2”]

You can of course open a web browser to do the same.

Don’t forget to stop the application if you want to continue as otherwise a file might get locked.

Start container

Install Docker on your mac unless you already have.
You can probably do whatever is described here on your Win10 machine with Docker for windows.
But I happen to have OSX and a virtualised Windows10 through Parallels. It is said to be possible to run Docker for windows in Parallels but then I have to fork out another 50€ (per year?) for the Pro version; and having a virtualised Windows to virtualise yet a machine creates a performance penalty also on the host OS. My machine is running warm and noisy as it is.

Start

> docker run -p80:80 -ti –rm -v /Users/username/Documents/PROJEKT/Solution1/WebApplication1/bin/Debug/netcoreapp1.1:/Web microsoft/aspnetcore  /bin/bash -c ‘cd /Web/publish; dotnet WebApplication1.dll’
Hosting environment: Production
Content root path: /Web/publish
Now listening on: http://+:80
Application started. Press Ctrl+C to shut down.

Caveat: For almost a full day I got the error message docker: invalid reference format.
which was somehow related to microsoft/dotnet:1.1.2-runtime
which was wrong because when I rewrote the very same text it suddenly started. My first guess was that there was a hidden character somewhere but I rewinded to an earlier command that had failed and suddenly it worked.

If you care already now about the parameters for docker run they are:

-p80:80
I did not want to make this quick start unnecessary complex by having lots of different ports so everything is running on port 80.
With that said; as Kestrel (the web server we instantiated in Program.cs runs in aspnet it talks on port 80. Then we open a hole in the container from port 80 to port 80. This latter is what -p80:80 means.

-ti
This gives us a terminal, of sorts, and something about how it receives commands.

-rm
This one cleans up after our run so there is no halted container wasting hard drive space when the container stops.

-v /User….:/Web…
This parameter lets the continer use /Web to reach folder /User… where we have put our code.

microsoft/aspnetcore
This is the name of the image we use. An image is to a container what a class is to an object.
In this article we don’t adapt the microsoft/aspnetcore image, created by microsoft especially to run aspnet core solutions, to anything but use it as it is.
As we have not specified a version we get the latest.
Microsoft has many images for different uses.

/bin/bas…tion1.dll’
Execute a command in bash.
The command happens to be “start the web server”.

Call the web server in the container

Then open another terminal and curl:

> curl localhost:80/api/values
[“value1″,”value2”]

Yay! The web server in the container runs your dotnet core web application.

Compile Aspnet core 1.1 outside Docker container but run within

Prerequisite

OSX

Docker

Dotnet core 1.1

A folder named (e.g.) /Users/yourname/Docker/Dandelion
and a folder named (e.g.) /Users/yourname/Docker/Dandelion/MyWeb

Create the web

In MyWeb run

Now we have a web site compiled and ready to run with [dotnet run].
You can run the app and then [curl localhost] to find out if it is runnable; but if you got no error message earlier all should be ok.

Create an image

Go to the Dandelion folder.

Create a file Dockerfile and paste into it:

Then, to create the image run

Note that the name must be all small caps.
Don’t miss the trailing period.

If you want to check that the image is created just execute [docker images] which should show the new image at the top of the list.

Start the container

Go to the Dandelion folder. (you are probably already standing there)

Execute

and your web should start.

Verify result

Either open another console and execute

or go to localhost in your web browser.

Create and run an Aspnet core 1.1 web site in Docker container on OSX

Prerequisite:

Docker and Dotnet Core 1.1 should be installed on the host (=OSX).

You have a folder somewhere, for instance /User/yourname/Documents/Docker/mywebapp.

Create the image

In your folder, create the dockerfile

Then execute

in a terminal in said folder.

If you now execute

you can se the new image as mynick/myimage.

Create the container and start the web server

In the terminal execute

Behold result

In a terminal execute

or in a web browser go to

Run Docker Dotnet core aspnet 1.1 web server with mounted executable on OSX

Prerequisite

Install docker.

Install Dotnet Core 1.1.

Create web application

Create a directory “theapp”.

Open a terminal and, in the directory, execute:

Check it works.

Execute, in a terminal:

Or is it

?

Create container

In a terminal execute:
(after you have have updated “YourRootedPathAndFolder” appropriately.

and when it is finished churning through the long list of modules open a new terminal and execute

on your host to receive a smaller waterfall of HTML.

That should be it.

Troubleshooting

If you forget to do the dotnet restore

You get something like:

Project theapp (.NETCoreApp,Version=v1.1) was previously compiled. Skipping compilation.

Error: assembly specified in the dependencies manifest was not found — package: ‘Microsoft.AspNetCore.Antiforgery’, version: ‘1.0.1’, path: ‘lib/netstandard1.3/Microsoft.AspNetCore.Antiforgery.dll’

Attach and request

Run

in a terminal. Note the Container ID.

Then execute, after the b5a…f5 is updated appropriately.

Now you have a shell inside the container and should be able to get a result from:

Create a Dotnet aspnet core 1.1 web server in OSX

Install Dotnet core à la https://www.microsoft.com/net/core#macos

Create a folder and to to it.

Open a terminal (one cannot reuse any terminal from before dotnet was installed since the path is updated) and execute:

Open another terminal and execute:

A pile of HTML should scroll into view.

In the first terminal you can see the reaction.

Running Dotnet aspnet 1.1 in a Docker container on OSX without any Windows

Prerequisite

Install Docker on OSX.

Create Dockerfile

Create a file named Dockerfile in a new folder.
Its contents are:

Create image

Run image

See output

On the host:

and you should se a whole dab of HTMl. You can also watch it in your browser.

Starting Dotnet aspnet core 1.1 on OSX in a Docker container

Install Docker on OSX.

https://docs.docker.com/docker-for-mac/

Prepare local drive

(This is strictly not necessary but if you skip this you have to remove the -v and following path from the docker run command further down. You will also have to mkdir the app folder in the container before cd to it.)

Go to you your local Documents folder. Create a Docker folder. Inside it create a dotnetcore folder. This results in /Users/myname/Documents/Docker/dotnetcore.

Start container

Open a terminal and execute (after exchanging “myname” to your user’s name)

This will download the microsoft/dotnet image, start it, connect your host’s dotnetcore folder to an app folder inside the container, set an environment variable, publish the internal port 80 on port 80 and finally open a terminal inside the container; all in one go.

Start the web server

Now inside the container execute

Absolutely not necessary but if you

you will see something like

Start the web server through

This will also compile the code before starting the application.

See output

If you open

in your host’s web browser you should now see a page about Dotnet aspnet core.

That all there is to it!

Trouble shooting

If you don’t check that the web server is running and listening on port 80 locally. This is done by opening a new terminal and check the ContainerID through

Then you attach a terminal to the running container.

(but with proper id)

Now, inside the container, run

and you should get a boatload of HTML back. In the other terminal window you should see some reaction to the request.

Links

More thourough but for version 1.0

https://store.docker.com/images/6c038a68-be47-4d7e-bfd2-33a6fe75b9ac?tab=description