Python is an interpreted programming language. By just tuping python you can start programming.
When you type,
$python
It willl display as;
>>>
here you can type your program.
To exit from it, you can type Crlt+d or quit().

# is used to comment

Interpreter can be used as a calculator.
>>> (25+5)/5
6

The equal sign in used to assign values to a variable
>>>a=100 # assign 100 to a
>>>b=2*5 # assign 2*5 (10) to b
>>>a+b
110

complplex numbers are also supported, like
>>>complex(3,5)+complex(5,-5)
10+0j

In the interactive mode, the last printed output is asigned to the _ variable. So you can use,
>>>100+50
>>> _/3 # this work as 150/3
50
to forword last output to some other task.

Strings in python
>>>word="hello \n world"
>>>print word
hello
world

If you are deviding the string in to two parts you should use a \ like
>>>word="hello \
...world"
>>>echo word
hello world

String concatination
>>>word='A'+'Help'
>>>print word
AHelp

String repeat
>>>word='-Help-'
>>>print word*3
-HELP--HELP--HELP-

String indexing
>>> word='HELP'
>>>word[2]
'L'
Note: The string index is starting from [0].

Some special thing
>>>word='colombo'
>>>word[2]
'l'
>>>word[:2] # will give [0]and [1]
'co'
>>>word[2:] # will give [2], [3], [4]..
'lombo'
>>>word[:2]+word[2:]
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  1. I tried to run bolt in my mac and got following error.


    MacBook-Pro:~ thilina$ bolt command run 'ls' -n 192.168.1.35 -u thilina
    Started on 192.168.1.35...
    dyld: lazy symbol binding failed: Symbol not found: _SHA512Init
      Referenced from: /opt/puppetlabs/bolt/lib/ruby/gems/2.5.0/gems/bcrypt_pbkdf-1.0.0/lib/bcrypt_pbkdf_ext.bundle
      Expected in: flat namespace
    
    dyld: Symbol not found: _SHA512Init
      Referenced from: /opt/puppetlabs/bolt/lib/ruby/gems/2.5.0/gems/bcrypt_pbkdf-1.0.0/lib/bcrypt_pbkdf_ext.bundle
      Expected in: flat namespace
    
    /opt/puppetlabs/bin/bolt: line 4: 74325 Abort trap: 6           env -u GEM_HOME -u GEM_PATH -u DLN_LIBRARY_PATH -u RUBYLIB -u RUBYLIB_PREFIX -u RUBYOPT -u RUBYPATH -u RUBYSHELL -u LD_LIBRARY_PATH -u LD_PRELOAD SHELL=/bin/sh /opt/puppetlabs/bolt/bin/bolt "$@"
    


    So I add my private key to ssh authentication agent using ssh-add. Following is to reproduce it and the workaround it until bolt devs give a proper patch [1].

    Reproduce:

    MacBook-Pro:~ thilina$ ssh-add -D
    All identities removed.
    MacBook-Pro:~ thilina$ bolt command run 'ls' -n 192.168.1.35 -u thilina
    Started on 192.168.1.35...
    dyld: lazy symbol binding failed: Symbol not found: _SHA512Init
      Referenced from: /opt/puppetlabs/bolt/lib/ruby/gems/2.5.0/gems/bcrypt_pbkdf-1.0.0/lib/bcrypt_pbkdf_ext.bundle
      Expected in: flat namespace
    
    dyld: Symbol not found: _SHA512Init
      Referenced from: /opt/puppetlabs/bolt/lib/ruby/gems/2.5.0/gems/bcrypt_pbkdf-1.0.0/lib/bcrypt_pbkdf_ext.bundle
      Expected in: flat namespace
    
    /opt/puppetlabs/bin/bolt: line 4: 74325 Abort trap: 6           env -u GEM_HOME -u GEM_PATH -u DLN_LIBRARY_PATH -u RUBYLIB -u RUBYLIB_PREFIX -u RUBYOPT -u RUBYPATH -u RUBYSHELL -u LD_LIBRARY_PATH -u LD_PRELOAD SHELL=/bin/sh /opt/puppetlabs/bolt/bin/bolt "$@"
    MacBook-Pro:~ thilina$


    Solution:

    MacBook-Pro:~ thilina$ ssh-add ~/.ssh/id_rsa
    Enter passphrase for ~/.ssh/id_rsa:
    Identity added: ~/.ssh/id_rsa (thilina)
    MacBook-Pro:~ thilina$


    Test:

    MacBook-Pro:~ thilina$ bolt command run 'ls' -n 192.168.1.35 -u thilina
    Started on 192.168.1.35...
    Finished on 192.168.1.35:
    Successful on 1 node: 192.168.1.35
    Ran on 1 node in 0.30 seconds
    MacBook-Pro:~ thilina$
    

    1

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  2. With StatefulSets running a mongo cluster with persistent storage is easy. Kubernetes blog post in [1] explains how to do that. But when we try to enable authentication there is a small problem with the above solution. Problem is we need to start the cluster without replica set (--replSet) option and add the admin user and a key file, then restart with the replica set and the key file.

    In order to do that we need to modify the above sample code to add a pod life cycle - post start command.

        spec:
          terminationGracePeriodSeconds: 10
          containers:
            - name: mongo
              image: mongo:3.4.9
              command:
              - /bin/sh
              - -c
              - >
                if [ -f /data/db/admin-user.lock ]; then
                  mongod --replSet rs0 --clusterAuthMode keyFile --keyFile /etc/secrets/mongo.key --setParameter authenticationMechanisms=SCRAM-SHA-1;
                else
                  mongod --auth;
                fi;
              lifecycle:
                postStart:
                  exec:
                    command:
                    - /bin/sh
                    - -c
                    - >
                      if [ ! -f /data/db/admin-user.lock ]; then
                        sleep 5;
                        touch /data/db/admin-user.lock
                        if [ "$HOSTNAME" = "mongo-0" ]; then
                          mongo --eval 'db = db.getSiblingDB("admin"); db.createUser({ user: "admin", pwd: "password", roles: [{ role: "root", db: "admin" }]});';
                        fi;
                        mongod --shutdown;
                      fi;
              ports:
                - containerPort: 27017
    If you look at the command section of the above statefulSet part you can see I'm checking for a lock file. If that file exists I will start the cluster with replica set option. Else I will start the cluster with just auth.

    Then you can notice the postStart section. In post start section we can define what to do at the start of a container in a pod. You can refer to this post in [2] to get an idea of pod lifecycle. In that it will again check for the lock file. If the file does not exists it will create the file and if the hostname is equal to mongo-o it will add the mongo admin user to the cluster. Then it will stop the node. Stopping the node will result the container to restart. Since we are using persistent storage the initially created lock file will exist. Since the lock file is there command will start the cluster with replica set option and postStart will pass its loop.

    Running the mongo cluster

    Generate a random key to enable keyFile authentication replication as described in this post.

    openssl rand -base64 741 > mongodb-keyfile
    Create a secret using that random string.
    kubectl create secret generic mongo-key --from-file=mongodb-keyfile
    Create statefulSet and headless service.
    kubectl create -f  https://gist.githubusercontent.com/thilinapiy/0c5abc2c0c28efe1bbe2165b0d8dc115/raw/d3d0e64dfd35158907d076422c362f289d124dfc/mongo-statefulset.yaml
    Scale-up if you need mote high availability.
    kubectl scale --replicas=3 statefulset mongo
    Let me know if you need further help.

    1. http://blog.kubernetes.io/2017/01/running-mongodb-on-kubernetes-with-statefulsets.html
    2. https://blog.openshift.com/kubernetes-pods-life
    3. https://docs.mongodb.com/manual/tutorial/enforce-keyfile-access-control-in-existing-replica-set/
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  3. Run kube proxy to use curl without authentication

    kubectl proxy

    Run the curl to watch the events and filter it with jq for pod starts and stops.

    curl -s 127.0.0.1:8001/api/v1/watch/events | jq --raw-output \ 'if .object.reason == "Started" then . elif .object.reason == "Killing" then . else empty end | [.object.firstTimestamp, .object.reason, .object.metadata.namespace, .object.metadata.name] | @csv'

    Output will be

    "2017-10-14T02:51:31Z","Killing","default","echo-1788535470-v3089.14ed5012be9b81d2" "2017-10-14T02:17:12Z","Started","default","hello-minikube-180744149-7sbj2.14ed4e335345db3d" "2017-10-14T02:17:15Z","Started","kube-system","default-http-backend-27b99.14ed4e341737f843" "2017-10-14T02:17:11Z","Started","kube-system","kube-addon-manager-minikube.14ed4e33195f434a" "2017-10-14T02:17:14Z","Started","kube-system","kube-dns-910330662-78fqv.14ed4e33d9790ee6" "2017-10-14T02:17:15Z","Started","kube-system","kube-dns-910330662-78fqv.14ed4e33e88e1b68" "2017-10-14T02:17:15Z","Started","kube-system","kube-dns-910330662-78fqv.14ed4e3404bfcffc" "2017-10-14T02:17:13Z","Started","kube-system","kube-state-metrics-3741290554-5cv05.14ed4e337556350c" "2017-10-14T02:17:13Z","Started","kube-system","kube-state-metrics-3741290554-5cv05.14ed4e33804c8647" "2017-10-14T02:17:15Z","Started","kube-system","kubernetes-dashboard-8991s.14ed4e340386d190" "2017-10-14T02:54:57Z","Killing","kube-system","kubernetes-dashboard-8991s.14ed5042a8fa1c81" "2017-10-14T02:54:58Z","Started","kube-system","kubernetes-dashboard-xd7h5.14ed5042d33aa3c7" "2017-10-14T02:17:16Z","Started","kube-system","nginx-ingress-controller-9qn5l.14ed4e3426ecdaa8" "2017-10-14T02:55:23Z","Killing","kube-system","nginx-ingress-controller-9qn5l.14ed50489b820cce" "2017-10-14T02:55:37Z","Started","kube-system","nginx-ingress-controller-rf6j3.14ed504c01cf90ea" "2017-10-14T02:17:13Z","Started","kube-system","prometheus-3898748193-jgxzk.14ed4e339109bcb4" "2017-10-14T02:17:14Z","Started","kube-system","prometheus-3898748193-jgxzk.14ed4e33af0e9433"
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  4. We are going to use openssl to generate a certificate with subject alternative names. When we use SANs in a certificate we can use the same certificate to front several websites with different domain names.

    First we need to generate a private key. Since we are going to use this in a web server like Nginx or apache I'm not going to encrypt the private key with a passphrase.


    openssl genrsa -out thilina.org.key 2048


    Then we need to have a configurations file to add those alternative names into the certificate signing request (CSR).

    sans.conf

    [ req ]
    default_bits       = 2048
    distinguished_name = req_distinguished_name
    req_extensions     = req_ext
    
    [ req_distinguished_name ]
    countryName         = Country Name (2 letter code)
    stateOrProvinceName = State or Province Name (full name)
    localityName        = Locality Name (eg, city)
    organizationName    = Organization Name (eg, company)
    commonName          = Common Name (e.g. server FQDN or YOUR name)
    
    [ req_ext ]
    subjectAltName = @alt_names
    
    [alt_names]
    DNS.1=thilina.org
    DNS.2=api.thilina.org
    DNS.3=gateway.thilina.org
    


    Now I'm going to generate the CSR in a single command.


    openssl req -new -key thilina.org.key -sha256 -nodes -out thilina.org.csr \
      -subj "/C=LK/ST=Colombo/L=Colombo/O=Thilina Piyasundara/OU=Home/CN=thilina.org" \
      -config san.conf
    


    Print and verify the CSR


    openssl req -in thilina.org.csr -text -noout



    Certificate Request:
        Data:
            Version: 1 (0x0)
            Subject: C = LK, ST = Colombo, L = Colombo, O = Thilina Piyasundara, OU = Home, CN = thilina.org
            Subject Public Key Info:
                Public Key Algorithm: rsaEncryption
                    Public-Key: (2048 bit)
                    Modulus:
                        00:d0:13:91:5d:62:7c:4f:57:6d:4c:79:85:59:d8:
                        c5:ae:50:41:cc:db:fe:b4:75:fc:c1:73:e7:a7:ac:
                        89:36:3b:26:08:0f:33:b0:96:5c:29:a1:ee:9a:14:
                        13:4b:5b:43:74:74:a2:fd:97:2b:2b:bd:2a:b8:e6:
                        22:d2:01:15:f3:7f:e9:d8:c9:d4:65:04:5a:ef:f0:
                        03:41:63:56:39:eb:5f:e5:90:de:33:b7:bb:60:0e:
                        e3:70:79:60:8f:cb:a9:71:3b:e3:0a:b1:17:47:aa:
                        41:08:b5:44:5e:1a:a1:fa:a2:ce:ed:18:c5:a3:b0:
                        6f:0f:57:ca:ae:28:7f:91:49:14:6b:94:4c:3c:33:
                        fb:27:ed:77:37:a7:d6:54:4e:a7:6e:bc:c9:a2:a1:
                        b5:f2:f0:aa:76:64:04:83:96:92:03:36:4c:3e:14:
                        0e:97:a6:79:9e:23:c1:2a:c4:7a:3d:6e:f3:1c:40:
                        e3:d1:61:f2:56:51:8f:0f:04:76:62:ea:b0:1f:94:
                        e8:a8:8b:54:d6:08:5a:79:a6:a4:a0:00:fb:5f:c3:
                        d5:d4:50:ea:15:12:ea:9b:10:cc:9a:d9:32:6e:48:
                        93:30:4b:e7:2e:fe:a9:a0:31:16:61:24:3f:29:54:
                        2a:25:da:d2:b3:6a:d9:d5:a9:51:ee:d3:bb:b9:83:
                        86:59
                    Exponent: 65537 (0x10001)
            Attributes:
            Requested Extensions:
                X509v3 Subject Alternative Name:
                    DNS:thilina.org, DNS:api.thilina.org, DNS:gateway.thilina.org
        Signature Algorithm: sha256WithRSAEncryption
             96:44:43:98:60:76:49:ad:8b:01:65:20:f1:ca:4a:47:84:67:
             dc:77:f0:2e:bb:30:68:8b:2f:79:c4:4c:10:91:ec:70:fe:73:
             9c:3e:f4:69:18:8c:34:f6:85:05:26:b1:2a:35:38:f5:93:59:
             c2:a4:07:83:73:79:88:9b:ff:17:99:66:34:58:21:bc:de:8e:
             65:b9:50:bb:18:52:53:9b:ed:a3:4e:c7:55:73:2e:42:47:dc:
             94:4d:fb:cc:ba:b1:7a:57:a6:f9:fa:27:a2:54:aa:cd:f6:79:
             3d:b7:0a:82:a3:18:41:ec:f5:db:cc:05:6a:43:64:d7:4a:00:
             fe:a3:89:f9:25:f3:79:55:f9:79:3a:b2:96:5e:9d:67:f5:c7:
             e4:ab:fc:da:cb:df:f5:76:36:44:fe:d2:87:3a:d7:a2:a9:2e:
             fc:7f:ba:a6:12:44:70:e0:c4:42:57:01:1e:51:0a:d4:2e:33:
             e2:63:20:c2:9a:07:1b:78:e8:fb:42:b5:e5:85:00:b1:2c:25:
             d8:ad:43:af:6a:01:09:59:7e:d0:af:dd:72:f3:93:18:30:38:
             c2:b0:6c:8e:88:79:4e:16:fe:e3:87:46:c2:eb:f3:2e:2b:aa:
             a7:a9:76:1d:fd:8b:d9:d9:1c:a3:1c:21:db:af:b0:0b:7e:15:
             37:37:0f:25
    



    Validate the key, csr and certificates are matching.

    openssl rsa -noout -modulus -in domain.key | openssl md5
    openssl x509 -noout -modulus -in domain.crt | openssl md5
    openssl req -noout -modulus -in domain.csr | openssl md5
    


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  5. First of all we have to have the spring-boot code in a git(svn) repo. I have create a sample spring-boot application using maven archetypes. You can find the code in;

    https://github.com/thilinapiy/SpringBoot

    Compile the code and generate the package using following command;
    # cd SpringBoot
    # mvn clean package
    
    This will build the app and create a jar file called 'SpringBoot-1.0.0.jar'.

    We can run the application with following command and it will start it in port 8080.
    # java -jar target/SpringBoot-1.0.0.jar
    
    Now we switch to the next part. In this we need to update the bitesize files according to our needs.

    https://github.com/thilinapiy/bitesize-spring

    First we'll update the 'build.bitesize' file. In this we need to update the projects and name accordingly and give the source code repo url and related details as in all other projects. But if you look at the shell commands you can see that I have modified few of those. I have add the 'mvn clean package' command and change the 'cp' command to copy the build jar to '/app' directory. Then it will build the deb as previous.
    project: spring-dev
    components:
      - name: spring-app
        os: linux
        repository:
          git: git@github.com:thilinapiy/SpringBoot.git
          branch: master
        build:
          - shell: sudo mkdir -p /app
          - shell: sudo mvn clean package
          - shell: sudo cp -rf target/*.jar /app
          - shell: sudo /usr/local/bin/fpm -s dir -n spring-app --iteration $(date "+%Y%m%d%H%M%S") -t deb /app
        artifacts:
          - location: "*.deb"
    
    Then we'll check the 'application.bitesize' file. I have change the 'runtime' to an ububtu-jdk8. Then change the command to run the jar.
    project: spring-dev
    applications:
      - name: spring-app
        runtime: ubuntu-jdk8:1.0
        version: "0.1.0"
        dependencies:
          - name: spring-app 
            type: debian-package
            origin:
              build: spring-app
            version: 1.0
        command: "java -jar /app/SpringBoot-1.0.0.jar"
    
    In the 'environments.bitesize' I have update the port to 8080.
    project: spring-dev
    environments:
      - name: production
        namespace: spring-dev
        deployment:
          method: rolling-upgrade
        services:
          - name: spring-app
            external_url: spring.dev-bite.io
            port: 8080 
            ssl: "false"
            replicas: 2
    
    In the stackstorm create_ns option give the correct manspace and the repo-url.
    Reference : http://docs.prsn.io//deployment-pipeline/readme.html
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  6. We need to grant 'dbadmin' privileges to a user called 'store_db_user' to their mondo database in a 4 node cluster.

    First we need to connect to the primary database of the cluster with super.

    # mongo -u supperuser -p password -h node1.mongo.local

    If you connect to the primary replica it will change the shell prompt to something like this;

    mongoreplicas:PRIMARY>

    Then you can list down the databases using following command.

    mongoreplicas:PRIMARY>show dbs
    admin     0.078GB
    local     2.077GB
    store_db  0.078GB
    

    Then switch to the relevant database;

    mongoreplicas:PRIMARY>use store_db

    And grant permissions;

    mongoreplicas:PRIMARY>db.grantRolesToUser(
      "store_db_user",
      [
        { role: "dbOwner", db: "store_db" },
      ]
    )

    Exit from the admin user and login to the cluster as the database user.

    # mongo -u store_db_user -p store_passwd -h node1.mongo.local/store_db

    Validate the change.

    mongoreplicas:PRIMARY>show users
    {
    	"_id" : "store_db.store_db_user",
    	"user" : "store_db_user",
    	"db" : "store_db",
    	"roles" : [
    		{
    			"role" : "dbOwner",
    			"db" : "store_db"
    		},
    		{
    			"role" : "readWrite",
    			"db" : "store_db"
    		}
    	]
    }

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  7. WSO2 App Cloud is now supporting Docker base PHP applications. In this blog post I will describe how to install a WordPress blog in this environment. In order to setup a WordPress environment we need to have two things;

    1. Web server with PHP support
    2. MySQL database

    If we have both of these we can start setting up WordPress. In WSO2 App Cloud we can use the PHP application as the WordPress hosting web server which is a PHP enabled Apache web server docker image. Also it provides a database service where you can easily create and manage MySQL databases via the App Cloud user interface (UI).

    Note:- 
    For the moment WSO2 App Cloud is on beta therefore these docker images will have only 12h of lifetime with no data persistence in the file storage level. Data on MySQL databases will be safe unless you override. If you need more help don't hesitate to contact Cloud support.

    Creating PHP application

    Signup or signin to WSO2 App Cloud via http://wso2.com/cloud. Then click on the "App Cloud beta" section.
    Then it will redirect you to the App Cloud user interface. Click on 'Add New Application' button on the left hand corner.
    This will prompt you to several available applications. Select 'PHP Web Application' box and continue.
    Then it will prompt you a wizard. In that give a proper name and a version to your application. Name and version will be use to generate the domain name for your application.

    There are several options that you can use to upload PHP content to this application. For the moment I will download the wordpress-X.X.X.zip file from the wordpress site and upload it to application.
    In the below sections of the UI you can set the run time and container specification. Give the highest Apache version as the runtime and use minimal container speck as wordpress does not require much processing and memory.
    If the things are all set and the file upload is complete click on 'Create' button. You will get the following status pop-up when you click the create button and it will redirect you to the application when its complete.
    In the application UI note the URL. Now you can click on the 'Launch App' button so that it will redirect you to your PHP application.
    Newly installed WordPress site will be like this.
    Now we need to provide database details to it. Therefore, we need to create database and a user.

    Creating database

    Go back to the Application UI and click on 'Back to listing' button.
    In that UI you can see a button in the top left hand corner called 'Create database'. Click on that.
    In the create database UI give a database name, database user name and a password . Password need to pass the password policy so you can click on 'Generate password' to generate a secure password easily. By the way of you use generate password option make sure you copy the generated password before you proceed with database creation. Otherwise you may need to reset the password.

    Also note that database name and database user name will append tenant domain and random string accordingly to the end of both. Therefore, those fields will only get few number of input characters.
    If all set then click on 'Create database' button to proceed. After successfully creating the database it will redirect you to a database management user interface like following.
    Now you can use those details to login to the newly create mysql database as follows;
    $ mysql -h mysql.storage.cloud.wso2.com -p'' -u
    eg :-
    $ mysql -h mysql.storage.cloud.wso2.com -p'XXXXXXXXX' -u admin_LeWvxS3l wpdb_thilina 
    Configuring WordPress

    If the database creation is successful and you can login to it without any issue we can use those details to configure WordPress.

    Go back to the WordPress UI and click on 'let's go' button. It will prompt to a database configuration wizard. Fill those fields with the details that we got from the previous section.
    If WordPress application can successfully establish a connection with the database using your inputs it will prompt you to a UI as follows.
    On that click on 'Run the install'. Then WordPress will start populating database tables and insert initial data to the given database.

    When its complete it will ask for some basic configurations like the site title, admin user name and passwords.
    Click on 'Install WordPress' after filling those information. Then it will redirect you to the WordPress admin console login page. Login to that using the username and password gave in the previous section.
    So now WordPress is ready to use. But the existing URL is not very attractive. If you have a domain you can use it as the base URL of this application.

    Setting custom domain (Optional)

    IN the application UI click on the top left three lines button shown in the following image.
    It will show some advance configuration that we can use. In that list select the last one 'Custom URL' option.
    It will prompt you following user interface. Enter the domain name that you are willing to use.
    But before you validate make sure you add a DNS CNAME to that domain pointing to you application launch URL.

    Following is the wizard that I got when adding the CNAME via Godaddy. This user interface and adding CNAME options will be different for you DNS provider.
    You can validate the CNAME by running 'dig' command in Linux or nslookup in windows.
    If the CNAME is working click on 'Update'.
     If that is successful you will get the above notification and if you access that domain name it will show your newly created WordPress blog.
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  8. Let's encrypt is a free and open certificate authority runs for the public benefit. This service is provided by the Internet Security Research Group and there are lots of companies working with them to make the Internet secure. People who have a domain name can get free SSL certificate for their websites using this service for three months. I they need to use for more than that three months we need to renew the certificate and its also for free. But the best thing is that this certificate is accepted by most of the new web browsers and systems by default. So you don't need to add CA certs to you browsers any more.

    In this article I will explain how we can use that service to get a free SSL certificate and add that to WSO2 API Cloud. So that you can have your own API store like;

    https://store.thilina.piyasundara.org

    In order to do that you need to have following things in hand.
    • Domain name.
    • Rights to add/delete/modify DNS A records and CNAMEs.
    • Publicly accessible webserver with root access or a home router with port forwarding capabilities. 

    Step 1

    If you have a publicly accessible webserver you can skip this step.If you don't have a publicly accessible webserver you can make your home PC/Laptop a temporary webserver if you can do port forwarding/NATing in you home router. I will show how I did that with my ADSL router. You can get help on port forwarding information by referring to this website http://portforward.com.

    a. Add a port forwarding rule in your home router.

    Get your local (laptop) IP (by running ifconfig/ip addr) and put that as the backend server in your router for. Set the WAN port as 80 and LAN port as 80.


    After adding the rule it will be like this.

    b. Start a webserver in your laptop. We can use the simple Python server for this. Make sure to check the IPTable rules/Firewall rules.

    mkdir /tmp/www
    cd /tmp/www/
    echo 'This is my home PC :)' > index.html
    sudo python3 -m http.server 80
    

    c. Get the public IP of your router. Go to this link : http://checkip.dyndns.org it will give the public IP address. This IP is changing time-to-time so no worries.


    d. Try to access that IP from a browser.
    If it is giving the expected output you have a publicly accessible webserver.


    Step 2

    Now we need to update a DNS entry. My expectation is to have a single SSL certificate for both domains 'store.thilina.piyasundara.org' and 'api.thilina.piyasundara.org'.

    a. Go to your DNS provides console and add an A record for both domain names to point to the public IP of your webserver (or the IP that we got from the previous step).


    b. Try to access both via a browser and if its giving the expected out put you can proceed to the next step.


    Step 3

    I'm follow the instruction in the 'let's encrypt' guide. As I'm using the python server I need to use the 'certonly' option when running the command to generate the certs.

    a. Get the git clone of the letsencrypt project.

    git clone https://github.com/letsencrypt/letsencrypt
    cd letsencrypt
    

    b. Run cert generation command. (this requires root/sudo access)

    ./letsencrypt-auto certonly --webroot -w /tmp/www/ -d store.thilina.piyasundara.org -d api.thilina.piyasundara.org
    

    If this succeed you can find the SSL keys and certs in '/etc/letsencrypt/live/store.thilina.piyasundara.org' location.

    Step 4

    Check the content of the certs. (Be root before you try to 'ls' that directory)

    openssl x509 -in cert.pem -text -noout
    

    Step 5

    Create an API in WSO2 API Cloud if you don't have one. Else start on adding a custom domain to your tenant.

    a. Remove both A records and add CNAME records to those two domains. Both should point to the domain 'customdns.api.cloud.wso2.com'.


    b. Now click on the 'Configure' option in the top options bar and select the 'Custom URL' option.


    c. Make ready you SSL certs. Copy 'cert.pem', 'chain.pem' and 'privkey.pem' to you home directory.

    d. Modify API store domain. Click on the modify button, add the domain name click on verify. It will take few seconds. If that succeed you have correctly configured the CNAME to point to WSO2 cloud.

    e. Add cert files to the API Cloud. The order should be the certificate (cert.pem), private key (privatekey.pem) and the CAs chain file (chain.pem). Again it will take sometime to verify uploaded details.


    f. Update the gateway domain same as the previous.

    Now if you go the API Store it will show something like this.



    g. Same way you can use the gateway domain when you need to invoke APIs.

    curl -X GET --header 'Accept: application/json' --header 'Authorization: Bearer ' 'https://gateway.api.cloud.wso2.com:8243/t/thilina/gituser/1.0.0/thilinapiy'
    

    Now you don't need '-k' option. If not make sure you operating system (CA list) is up to date.

    Step 6

    Make sure to remove port forwarding in you home router if you use that and any changes that you make while obtaining the SSL certificates.

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  9. Docker is an open-source project to easily create lightweight, portable, self-sufficient containers from any application. There are two ways to run docker container;

    1. Run a pre-build docker image.
    2. Build your own docker image and use it.

    In the first option you can use a base image like Ubuntu, CentOS or an image built by someone else like thilina/ubuntu_puppetmaster. You can find these images index.docker.io

    In the second option you can build the image using a "Dockerfile". In this approach we can do customizations to the container by editing this file.

    When creating a docker container for WSO2 products option 2 is the best. I have wrote a sample Dockerfile on github. It describes how to build a Docker container for WSO2 API manager single node implementation. For the moment docker have some limitations like unable to edit the '/etc/hosts' file, etc. If you need to create a clusters of WSO2 products (an API manager cluster in this case) you need to do some additional things like setting up a DNS server, etc.

    How to build an API manager docker container?


    Get a git clone of the build repository.
    git clone https://github.com/thilinapiy/dockerfiles
    Download Oracle JDK 7 tar.gz (not JDK 8) and place it in '/dockerfiles/base/dist/'
    mv /jdk-7u55-linux-x64.tar.gz /dockerfiles/base/dist/
    Download WSO2 API manager and place that in '/dockerfiles/base/dist/'
    mv /wso2am-1.6.0.zip /dockerfiles/base/dist/
    Change directory to '/dockerfiles/base/'.
    cd dockerfiles/base/
    Run docker command to build image.
    docker build -t apim_image .

    How to start API manager from the build image?


    Start in interactive mode
    docker run -i -t --name apim_test apim_image
    Start in daemon mode
    docker run -d    --name apim_test apim_image
    Other options that can use when starting a docker image
    --dns  < dns server address >
    --host < hostname of the container >

    Major disadvantages in docker (for the moment)

    • Can't edit the '/etc/hosts' file in the container.
    • Can't edit the '/etc/hostname' file. --host option can use to set a hostname when starting.
    • Can't change DNS server settings in '/etc/resolve.conf'. --dns option can use to set DNS servers. Therefore, if you need to create a WSO2 product cluster you need to setup a  DNS server too.

    Read more about WSO2 API manager : Getting Started with API Manager


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  10. On Ubuntu 14.04 Python 3 is the default python version. Therefor If you try to run previous appindicator scripts on Ubuntu 14.04 those will not work. This script is done using Python 3 and relevant libraries.

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