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Added method to get and set hostname to Hosts class #123

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Merged
merged 4 commits into from
Sep 29, 2015
Merged

Added method to get and set hostname to Hosts class #123

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5f550ba
Added method to set hostname to Hosts class
carbonin Sep 25, 2015
f8176d7
Added method to get hostname to Hosts class
carbonin Sep 25, 2015
fca1a74
Added condition to handle the case where hostnamectl is not installed
carbonin Sep 28, 2015
44398ae
Cleaned up host specs
carbonin Sep 29, 2015
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16 changes: 16 additions & 0 deletions lib/linux_admin/hosts.rb
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Original file line number Diff line number Diff line change
@@ -1,5 +1,7 @@
module LinuxAdmin
class Hosts
include Common

attr_accessor :filename
attr_accessor :raw_lines
attr_accessor :parsed_file
Expand Down Expand Up @@ -36,6 +38,20 @@ def update_entry(address, hostname, comment = nil)
end
end

def hostname=(name)
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Do we want to add the logic to add the machine's IP address to the /etc/hosts file (https://github.com/ManageIQ/manageiq-appliance/blob/master/LINK/usr/bin/miqnet.sh#L167) here or have the caller do it in a separate call?
@Fryguy @bdunne

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If you are setting ip address, would you ensure that if you set a different ip address, it clears out the old ip address from /etc/hosts
If you are changing the hostname, do we also clear that out.

man, the use cases around this are complicated.

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I would say that the safest way to go would be to do as little as possible with each call. I don't really want to assume what people will want to do with these tools. I think it will be more clear from the calling code to do something like this https://github.com/ManageIQ/manageiq/pull/4558/files#diff-16bd2bb3c0abfe4c0381896614e7b987R238

if cmd?("hostnamectl")
run!(cmd('hostnamectl'), :params => ['set-hostname', name])
else
File.write("/etc/hostname", name)
run!(cmd('hostname'), :params => {:file => "/etc/hostname"})
end
end

def hostname
result = run(cmd("hostname"))
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We already require activesupport/core_ext so you could simplify this if there is nothing on output when unsuccessful.

run(cmd("hostname")).output.presence

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I'm not sure about what will be on output. It depends really on what Open3.capture3 returns here (https://github.com/ManageIQ/awesome_spawn/blob/master/lib/awesome_spawn.rb#L119) and what hostname returns in whatever failure case happened.

result.success? ? result.output : nil
end

private
def parse_file
@parsed_file = []
Expand Down
42 changes: 42 additions & 0 deletions spec/hosts_spec.rb
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
describe LinuxAdmin::Hosts do
TEST_HOSTNAME = "test-hostname"
etc_hosts = "\n #Some Comment\n127.0.0.1\tlocalhost localhost.localdomain # with a comment\n127.0.1.1 my.domain.local"
before do
allow(File).to receive(:read).and_return(etc_hosts)
Expand Down Expand Up @@ -50,4 +51,45 @@
expect(@instance.raw_lines).to eq(expected_array)
end
end

describe "#hostname=" do
it "sets the hostname using hostnamectl when the command exists" do
spawn_args = [
@instance.cmd('hostnamectl'),
:params => ['set-hostname', TEST_HOSTNAME]
]
expect(@instance).to receive(:cmd?).with("hostnamectl").and_return(true)
expect(AwesomeSpawn).to receive(:run!).with(*spawn_args)
@instance.hostname = TEST_HOSTNAME
end

it "sets the hostname with hostname when hostnamectl does not exist" do
spawn_args = [
@instance.cmd('hostname'),
:params => {:file => "/etc/hostname"}
]
expect(@instance).to receive(:cmd?).with("hostnamectl").and_return(false)
expect(File).to receive(:write).with("/etc/hostname", TEST_HOSTNAME)
expect(AwesomeSpawn).to receive(:run!).with(*spawn_args)
@instance.hostname = TEST_HOSTNAME
end
end

describe "#hostname" do
let(:spawn_args) do
[@instance.cmd('hostname'), {}]
end

it "returns the hostname" do
result = AwesomeSpawn::CommandResult.new("", TEST_HOSTNAME, nil, 0)
expect(AwesomeSpawn).to receive(:run).with(*spawn_args).and_return(result)
expect(@instance.hostname).to eq(TEST_HOSTNAME)
end

it "returns nil when the command fails" do
result = AwesomeSpawn::CommandResult.new("", "", "An error has happened", 1)
expect(AwesomeSpawn).to receive(:run).with(*spawn_args).and_return(result)
expect(@instance.hostname).to be_nil
end
end
end